feat: add SSE keepalive and liveness tracking for resilient connections

Add 30s keepalive pings to prevent proxy/CDN idle timeouts from killing
SSE connections silently. Track lastSeenAt on each SSE connect attempt
so Datastar's retry signals keep contexts alive through the reaper.

.claude/commands/release.md

@@ -0,0 +1,14 @@
+Create a new release for this project. Steps:
+
+1. Fetch tags from all remotes so the version list is current.
+2. Check for uncommitted changes. If any exist, commit them with a clean semantic commit message. No Claude attribution lines.
+3. Review the commits since the last tag. Based on their content, recommend a semver bump:
+   - **major**: breaking/incompatible API changes
+   - **minor**: new features, meaningful new behavior
+   - **patch**: bug fixes, docs, refactoring with no new features
+   Present the proposed version, the bump rationale, and the commit list. Wait for user approval before continuing.
+4. Tag the new version and push the tag + commits to all remotes (origin, gitea, etc.).
+5. Generate release notes from the commits since the last tag, grouped by type (features, fixes, docs/refactoring).
+6. Create a GitHub release using `gh release create`.
+7. Create a Gitea release using `tea releases create` with the same notes.
+8. Report both release URLs and confirm all remotes are up to date.

.gitignore

@@ -48,6 +48,7 @@ internal/examples/plugins/plugins
 internal/examples/realtimechart/realtimechart
 internal/examples/shakespeare/shakespeare
 internal/examples/nats-chatroom/nats-chatroom
+/nats-chatroom
 
 # NATS data directory
 data/

actiontrigger.go

@@ -3,6 +3,7 @@ package via
 import (
 	"fmt"
 	"strconv"
+	"time"
 
 	"github.com/ryanhamamura/via/h"
 )
@@ -23,6 +24,8 @@ type triggerOpts struct {
 	value          string
 	window         bool
 	preventDefault bool
+	debounce       time.Duration
+	throttle       time.Duration
 }
 
 type withSignalOpt struct {
@@ -58,6 +61,41 @@ func WithPreventDefault() ActionTriggerOption {
 	return withPreventDefaultOpt{}
 }
 
+type withDebounceOpt struct{ d time.Duration }
+
+func (o withDebounceOpt) apply(opts *triggerOpts) { opts.debounce = o.d }
+
+// WithDebounce adds a debounce modifier to the event trigger.
+func WithDebounce(d time.Duration) ActionTriggerOption { return withDebounceOpt{d} }
+
+type withThrottleOpt struct{ d time.Duration }
+
+func (o withThrottleOpt) apply(opts *triggerOpts) { opts.throttle = o.d }
+
+// WithThrottle adds a throttle modifier to the event trigger.
+func WithThrottle(d time.Duration) ActionTriggerOption { return withThrottleOpt{d} }
+
+// formatDuration renders a duration as e.g. "200ms" for Datastar modifiers.
+func formatDuration(d time.Duration) string {
+	return fmt.Sprintf("%dms", d.Milliseconds())
+}
+
+// buildAttrKey constructs a Datastar attribute key with modifiers.
+// Order: event → debounce/throttle → window.
+func buildAttrKey(event string, opts *triggerOpts) string {
+	key := "on:" + event
+	if opts.debounce > 0 {
+		key += "__debounce." + formatDuration(opts.debounce)
+	}
+	if opts.throttle > 0 {
+		key += "__throttle." + formatDuration(opts.throttle)
+	}
+	if opts.window {
+		key += "__window"
+	}
+	return key
+}
+
 // WithSignal sets a signal value before triggering the action.
 func WithSignal(sig *signal, value string) ActionTriggerOption {
 	return withSignalOpt{
@@ -97,62 +135,62 @@ func actionURL(id string) string {
 // to element nodes in a view.
 func (a *actionTrigger) OnClick(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:click", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("click", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnChange returns a via.h DOM attribute that triggers on input change. It can be added
 // to element nodes in a view.
 func (a *actionTrigger) OnChange(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:change__debounce.200ms", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("change", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnSubmit returns a via.h DOM attribute that triggers on form submit.
 func (a *actionTrigger) OnSubmit(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:submit", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("submit", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnInput returns a via.h DOM attribute that triggers on input (without debounce).
 func (a *actionTrigger) OnInput(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:input", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("input", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnFocus returns a via.h DOM attribute that triggers when the element gains focus.
 func (a *actionTrigger) OnFocus(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:focus", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("focus", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnBlur returns a via.h DOM attribute that triggers when the element loses focus.
 func (a *actionTrigger) OnBlur(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:blur", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("blur", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnMouseEnter returns a via.h DOM attribute that triggers when the mouse enters the element.
 func (a *actionTrigger) OnMouseEnter(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:mouseenter", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("mouseenter", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnMouseLeave returns a via.h DOM attribute that triggers when the mouse leaves the element.
 func (a *actionTrigger) OnMouseLeave(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:mouseleave", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("mouseleave", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnScroll returns a via.h DOM attribute that triggers on scroll.
 func (a *actionTrigger) OnScroll(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:scroll", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("scroll", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnDblClick returns a via.h DOM attribute that triggers on double click.
 func (a *actionTrigger) OnDblClick(options ...ActionTriggerOption) h.H {
 	opts := applyOptions(options...)
-	return h.Data("on:dblclick", buildOnExpr(actionURL(a.id), &opts))
+	return h.Data(buildAttrKey("dblclick", &opts), buildOnExpr(actionURL(a.id), &opts))
 }
 
 // OnKeyDown returns a via.h DOM attribute that triggers when a key is pressed.
@@ -164,11 +202,7 @@ func (a *actionTrigger) OnKeyDown(key string, options ...ActionTriggerOption) h.
 	if key != "" {
 		condition = fmt.Sprintf("evt.key==='%s' &&", key)
 	}
-	attrName := "on:keydown"
-	if opts.window {
-		attrName = "on:keydown__window"
-	}
-	return h.Data(attrName, fmt.Sprintf("%s%s", condition, buildOnExpr(actionURL(a.id), &opts)))
+	return h.Data(buildAttrKey("keydown", &opts), fmt.Sprintf("%s%s", condition, buildOnExpr(actionURL(a.id), &opts)))
 }
 
 // KeyBinding pairs a key with an action and per-binding options.

computed.go

@@ -0,0 +1,55 @@
+package via
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/ryanhamamura/via/h"
+)
+
+// computedSignal is a read-only signal whose value is derived from other signals.
+// It recomputes on every read and is included in patches only when the value changes.
+type computedSignal struct {
+	id      string
+	compute func() string
+	lastVal string
+	changed bool
+}
+
+func (s *computedSignal) ID() string {
+	return s.id
+}
+
+func (s *computedSignal) String() string {
+	return s.compute()
+}
+
+func (s *computedSignal) Int() int {
+	if n, err := strconv.Atoi(s.String()); err == nil {
+		return n
+	}
+	return 0
+}
+
+func (s *computedSignal) Bool() bool {
+	val := strings.ToLower(s.String())
+	return val == "true" || val == "1" || val == "yes" || val == "on"
+}
+
+func (s *computedSignal) Text() h.H {
+	return h.Span(h.Data("text", "$"+s.id))
+}
+
+// recompute calls the compute function and sets changed if the value differs from lastVal.
+func (s *computedSignal) recompute() {
+	val := s.compute()
+	if val != s.lastVal {
+		s.lastVal = val
+		s.changed = true
+	}
+}
+
+func (s *computedSignal) patchValue() string {
+	return fmt.Sprintf("%v", s.lastVal)
+}

computed_test.go

@@ -0,0 +1,190 @@
+package via
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+
+	"github.com/ryanhamamura/via/h"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestComputedBasic(t *testing.T) {
+	v := New()
+	var cs *computedSignal
+	v.Page("/", func(c *Context) {
+		sig1 := c.Signal("hello")
+		sig2 := c.Signal("world")
+		cs = c.Computed(func() string {
+			return sig1.String() + " " + sig2.String()
+		})
+		c.View(func() h.H { return h.Div() })
+	})
+	assert.Equal(t, "hello world", cs.String())
+}
+
+func TestComputedReactivity(t *testing.T) {
+	v := New()
+	var cs *computedSignal
+	var sig1 *signal
+	v.Page("/", func(c *Context) {
+		sig1 = c.Signal("a")
+		sig2 := c.Signal("b")
+		cs = c.Computed(func() string {
+			return sig1.String() + sig2.String()
+		})
+		c.View(func() h.H { return h.Div() })
+	})
+	assert.Equal(t, "ab", cs.String())
+	sig1.SetValue("x")
+	assert.Equal(t, "xb", cs.String())
+}
+
+func TestComputedInt(t *testing.T) {
+	v := New()
+	var cs *computedSignal
+	v.Page("/", func(c *Context) {
+		sig := c.Signal(21)
+		cs = c.Computed(func() string {
+			return fmt.Sprintf("%d", sig.Int()*2)
+		})
+		c.View(func() h.H { return h.Div() })
+	})
+	assert.Equal(t, 42, cs.Int())
+}
+
+func TestComputedBool(t *testing.T) {
+	v := New()
+	var cs *computedSignal
+	v.Page("/", func(c *Context) {
+		sig := c.Signal("true")
+		cs = c.Computed(func() string {
+			return sig.String()
+		})
+		c.View(func() h.H { return h.Div() })
+	})
+	assert.True(t, cs.Bool())
+}
+
+func TestComputedText(t *testing.T) {
+	v := New()
+	var cs *computedSignal
+	v.Page("/", func(c *Context) {
+		cs = c.Computed(func() string { return "hi" })
+		c.View(func() h.H { return h.Div() })
+	})
+
+	var buf bytes.Buffer
+	err := cs.Text().Render(&buf)
+	assert.NoError(t, err)
+	assert.Contains(t, buf.String(), `data-text="$`+cs.ID()+`"`)
+}
+
+func TestComputedChangeDetection(t *testing.T) {
+	v := New()
+	var ctx *Context
+	var sig *signal
+	v.Page("/", func(c *Context) {
+		ctx = c
+		sig = c.Signal("a")
+		c.Computed(func() string {
+			return sig.String() + "!"
+		})
+		c.View(func() h.H { return h.Div() })
+	})
+
+	// First patch includes computed (changed=true from init)
+	patch1 := ctx.prepareSignalsForPatch()
+	assert.NotEmpty(t, patch1)
+
+	// Second patch: nothing changed, computed should not be included
+	patch2 := ctx.prepareSignalsForPatch()
+	// Regular signal still has changed=true (not reset in prepareSignalsForPatch),
+	// but computed should not appear since its value didn't change.
+	hasComputed := false
+	ctx.signals.Range(func(_, value any) bool {
+		if cs, ok := value.(*computedSignal); ok {
+			_, inPatch := patch2[cs.ID()]
+			hasComputed = inPatch
+		}
+		return true
+	})
+	assert.False(t, hasComputed)
+
+	// After changing dependency, computed should reappear
+	sig.SetValue("b")
+	patch3 := ctx.prepareSignalsForPatch()
+	found := false
+	ctx.signals.Range(func(_, value any) bool {
+		if cs, ok := value.(*computedSignal); ok {
+			if v, ok := patch3[cs.ID()]; ok {
+				assert.Equal(t, "b!", v)
+				found = true
+			}
+		}
+		return true
+	})
+	assert.True(t, found)
+}
+
+func TestComputedInComponent(t *testing.T) {
+	v := New()
+	var cs *computedSignal
+	var parentCtx *Context
+	v.Page("/", func(c *Context) {
+		parentCtx = c
+		c.Component(func(comp *Context) {
+			sig := comp.Signal("via")
+			cs = comp.Computed(func() string {
+				return "hello " + sig.String()
+			})
+			comp.View(func() h.H { return h.Div() })
+		})
+		c.View(func() h.H { return h.Div() })
+	})
+
+	assert.Equal(t, "hello via", cs.String())
+	// Verify it's stored on the parent page context
+	found := false
+	parentCtx.signals.Range(func(_, value any) bool {
+		if stored, ok := value.(*computedSignal); ok && stored.ID() == cs.ID() {
+			found = true
+		}
+		return true
+	})
+	assert.True(t, found)
+}
+
+func TestComputedIsReadOnly(t *testing.T) {
+	// Compile-time guarantee: *computedSignal has no Bind() or SetValue() methods.
+	// This test exists as documentation — if someone adds those methods, the
+	// interface assertion below will need updating and serve as a reminder.
+	var cs interface{} = &computedSignal{}
+	type writable interface {
+		SetValue(any)
+	}
+	type bindable interface {
+		Bind() h.H
+	}
+	_, isWritable := cs.(writable)
+	_, isBindable := cs.(bindable)
+	assert.False(t, isWritable, "computedSignal must not have SetValue")
+	assert.False(t, isBindable, "computedSignal must not have Bind")
+}
+
+func TestComputedInjectSignalsSkips(t *testing.T) {
+	v := New()
+	var ctx *Context
+	var cs *computedSignal
+	v.Page("/", func(c *Context) {
+		ctx = c
+		cs = c.Computed(func() string { return "fixed" })
+		c.View(func() h.H { return h.Div() })
+	})
+
+	// Simulate browser sending back a value for the computed signal — should be ignored
+	ctx.injectSignals(map[string]any{
+		cs.ID(): "injected",
+	})
+	assert.Equal(t, "fixed", cs.String())
+}

configuration.go

@@ -57,9 +57,14 @@ type Options struct {
 	// embedded NATS backend, or supply any PubSub implementation.
 	PubSub PubSub
 
+	// ContextSuspendAfter is the time a context may be disconnected before
+	// the reaper suspends it (frees page resources but keeps the context
+	// shell for seamless re-init on reconnect). Default: 15m.
+	ContextSuspendAfter time.Duration
+
 	// ContextTTL is the maximum time a context may exist without an SSE
-	// connection before the background reaper disposes it.
-	// Default: 30s. Negative value disables the reaper.
+	// connection before the background reaper fully disposes it.
+	// Default: 1h. Negative value disables the reaper.
 	ContextTTL time.Duration
 
 	// ActionRateLimit configures the default token-bucket rate limiter for

context.go

@@ -42,6 +42,8 @@ type Context struct {
 	createdAt           time.Time
 	sseConnected        atomic.Bool
 	sseDisconnectedAt   atomic.Pointer[time.Time]
+	lastSeenAt          atomic.Pointer[time.Time]
+	suspended           atomic.Bool
 }
 
 // View defines the UI rendered by this context.
@@ -206,6 +208,40 @@ func (c *Context) Signal(v any) *signal {
 
 }
 
+// Computed creates a read-only signal whose value is derived from the given function.
+// The function is called on every read (String/Int/Bool) for fresh values,
+// and during sync to detect changes for browser patches.
+//
+// Computed signals cannot be bound to inputs or set manually.
+//
+// Example:
+//
+//	full := c.Computed(func() string {
+//	    return first.String() + " " + last.String()
+//	})
+//	c.View(func() h.H {
+//	    return h.Span(full.Text())
+//	})
+func (c *Context) Computed(fn func() string) *computedSignal {
+	sigID := genRandID()
+	initial := fn()
+	cs := &computedSignal{
+		id:      sigID,
+		compute: fn,
+		lastVal: initial,
+		changed: true,
+	}
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.isComponent() {
+		c.parentPageCtx.signals.Store(sigID, cs)
+	} else {
+		c.signals.Store(sigID, cs)
+	}
+	return cs
+}
+
 func (c *Context) injectSignals(sigs map[string]any) {
 	if sigs == nil {
 		c.app.logErr(c, "signal injection failed: nil signals")
@@ -247,7 +283,8 @@ func (c *Context) prepareSignalsForPatch() map[string]any {
 	defer c.mu.RUnlock()
 	updatedSigs := make(map[string]any)
 	c.signals.Range(func(sigID, value any) bool {
-		if sig, ok := value.(*signal); ok {
+		switch sig := value.(type) {
+		case *signal:
 			if sig.err != nil {
 				c.app.logWarn(c, "signal '%s' is out of sync: %v", sig.id, sig.err)
 				return true
@@ -255,6 +292,12 @@ func (c *Context) prepareSignalsForPatch() map[string]any {
 			if sig.changed {
 				updatedSigs[sigID.(string)] = fmt.Sprintf("%v", sig.val)
 			}
+		case *computedSignal:
+			sig.recompute()
+			if sig.changed {
+				updatedSigs[sigID.(string)] = sig.patchValue()
+				sig.changed = false
+			}
 		}
 		return true
 	})
@@ -400,6 +443,13 @@ func (c *Context) resetPageState() {
 	c.mu.Unlock()
 }
 
+// suspend frees page-scoped resources while keeping the context shell alive
+// in the registry for seamless re-init on reconnect.
+func (c *Context) suspend() {
+	c.resetPageState()
+	c.suspended.Store(true)
+}
+
 // Navigate performs an SPA navigation to the given path. It resets page state,
 // runs the target page's init function (with middleware), and pushes the new
 // view over the existing SSE connection with a view transition animation.

docs/getting-started.md

@@ -0,0 +1,179 @@
+# Getting Started
+
+Via is a server-side reactive web framework for Go. The browser connects over SSE (Server-Sent Events), and all state lives on the server — signals, actions, and view rendering happen in Go. The browser is a thin display layer that Datastar keeps in sync via DOM morphing.
+
+## Core Loop
+
+Every Via app follows the same pattern:
+
+```go
+package main
+
+import (
+    "github.com/ryanhamamura/via"
+    "github.com/ryanhamamura/via/h"
+)
+
+func main() {
+    v := via.New()
+
+    v.Config(via.Options{
+        DocumentTitle: "My App",
+    })
+
+    v.Page("/", func(c *via.Context) {
+        count := 0
+        step := c.Signal(1)
+
+        increment := c.Action(func() {
+            count += step.Int()
+            c.Sync()
+        })
+
+        c.View(func() h.H {
+            return h.Div(
+                h.P(h.Textf("Count: %d", count)),
+                h.Label(
+                    h.Text("Step: "),
+                    h.Input(h.Type("number"), step.Bind()),
+                ),
+                h.Button(h.Text("+"), increment.OnClick()),
+            )
+        })
+    })
+
+    v.Start()
+}
+```
+
+What happens:
+
+1. `via.New()` creates the app, starts an embedded NATS server, and registers internal routes (`/_sse`, `/_action/{id}`, `/_navigate`, `/_session/close`).
+2. `v.Config()` applies settings.
+3. `v.Page()` registers a route. The init function receives a `*Context` where you define signals, actions, and the view.
+4. `v.Start()` starts the HTTP server and blocks until SIGINT/SIGTERM.
+
+When a browser hits the page, Via creates a new `Context`, runs the init function, renders the full HTML document, and opens an SSE connection. From that point, every `c.Sync()` re-renders the view and pushes a DOM patch to the browser.
+
+## Configuration
+
+```go
+v.Config(via.Options{
+    DevMode:         true,
+    ServerAddress:   ":8080",
+    LogLevel:        via.LogLevelDebug,
+    DocumentTitle:   "My App",
+    Plugins:         []via.Plugin{MyPlugin},
+    SessionManager:  sm,
+    PubSub:          customBackend,
+    ContextTTL:      60 * time.Second,
+    ActionRateLimit: via.RateLimitConfig{Rate: 20, Burst: 40},
+})
+```
+
+| Field | Default | Description |
+|-------|---------|-------------|
+| `DevMode` | `false` | Enables context persistence across restarts, console logger, and Datastar inspector widget |
+| `ServerAddress` | `":3000"` | HTTP listen address |
+| `LogLevel` | `InfoLevel` | Minimum log level. Use `via.LogLevelDebug`, `LogLevelInfo`, `LogLevelWarn`, `LogLevelError` |
+| `Logger` | (auto) | Replace the default logger entirely. When set, `LogLevel` and `DevMode` have no effect on logging |
+| `DocumentTitle` | `"⚡ Via"` | The `<title>` of the HTML document |
+| `Plugins` | `nil` | Slice of plugin functions executed during `Config()` |
+| `SessionManager` | in-memory | Cookie-based session manager. See [PubSub and Sessions](pubsub-and-sessions.md) |
+| `DatastarContent` | (embedded) | Custom Datastar JS bytes |
+| `DatastarPath` | `"/_datastar.js"` | URL path for the Datastar script |
+| `PubSub` | embedded NATS | Custom PubSub backend. Replaces the default NATS. See [PubSub and Sessions](pubsub-and-sessions.md) |
+| `ContextTTL` | `30s` | Max time a context survives without an SSE connection before cleanup. Negative value disables the reaper |
+| `ActionRateLimit` | `10 req/s, burst 20` | Default token-bucket rate limiter for action endpoints. Rate of `-1` disables limiting |
+
+## Static Files
+
+Serve files from a directory:
+
+```go
+v.Static("/assets/", "./static")
+```
+
+Or from an embedded filesystem:
+
+```go
+//go:embed static
+var staticFS embed.FS
+
+v.StaticFS("/assets/", staticFS)
+```
+
+Both disable directory listing and return 404 for directory paths.
+
+## Head and Foot Injection
+
+Add elements to every page's `<head>` or end of `<body>`:
+
+```go
+v.AppendToHead(
+    h.Link(h.Rel("stylesheet"), h.Href("/assets/style.css")),
+    h.Meta(h.Attr("name", "viewport"), h.Attr("content", "width=device-width, initial-scale=1")),
+)
+
+v.AppendToFoot(
+    h.Script(h.Src("/assets/app.js")),
+)
+```
+
+These are additive and affect all pages globally.
+
+## Plugins
+
+A plugin is a `func(v *via.V)` that mutates the app during configuration — registering routes, injecting assets, or applying middleware.
+
+```go
+func PicoCSSPlugin(v *via.V) {
+    v.HTTPServeMux().HandleFunc("GET /css/pico.css", func(w http.ResponseWriter, r *http.Request) {
+        w.Header().Set("Content-Type", "text/css")
+        w.Write(picoCSSBytes)
+    })
+    v.AppendToHead(h.Link(h.Rel("stylesheet"), h.Href("/css/pico.css")))
+}
+
+// Usage:
+v.Config(via.Options{
+    Plugins: []via.Plugin{PicoCSSPlugin},
+})
+```
+
+Plugins have full access to the `*V` public API: `HTTPServeMux()`, `AppendToHead()`, `AppendToFoot()`, `Config()`, etc.
+
+## DevMode
+
+Enable during development for a better feedback loop:
+
+```go
+v.Config(via.Options{DevMode: true})
+```
+
+What it does:
+
+- **Console logger** — Human-readable log output with timestamps.
+- **Context persistence** — Saves context-to-route mappings to `.via/devmode/ctx.json`. On server restart, reconnecting browsers restore their state instead of getting a blank page. Pair with [Air](https://github.com/air-verse/air) for hot-reloading.
+- **Datastar inspector** — Injects a widget showing live signal values and SSE activity.
+
+## Custom HTTP Handlers
+
+Access the underlying `*http.ServeMux` for custom routes:
+
+```go
+mux := v.HTTPServeMux()
+mux.HandleFunc("GET /api/health", func(w http.ResponseWriter, r *http.Request) {
+    w.Write([]byte("ok"))
+})
+```
+
+Register custom handlers before calling `v.Start()`.
+
+## Next Steps
+
+- [State and Interactivity](state-and-interactivity.md) — Signals, actions, components, validation
+- [Routing and Navigation](routing-and-navigation.md) — Multi-page apps, middleware, SPA navigation
+- [PubSub and Sessions](pubsub-and-sessions.md) — Real-time messaging, persistent sessions
+- [HTML DSL](html-dsl.md) — The `h` package reference
+- [Project Structure](project-structure.md) — Organizing files as your app grows

docs/html-dsl.md

@@ -0,0 +1,164 @@
+# HTML DSL
+
+Reference for the `h` package — Via's HTML builder.
+
+## Overview
+
+The `h` package wraps [gomponents](https://github.com/maragudk/gomponents) with a single interface:
+
+```go
+type H interface {
+    Render(w io.Writer) error
+}
+```
+
+Every element, attribute, and text node implements `H`. Build HTML by nesting function calls:
+
+```go
+import "github.com/ryanhamamura/via/h"
+
+h.Div(h.Class("card"),
+    h.H2(h.Text("Title")),
+    h.P(h.Textf("Count: %d", count)),
+    h.Button(h.Text("Click"), action.OnClick()),
+)
+```
+
+For cleaner templates, use a dot import:
+
+```go
+import . "github.com/ryanhamamura/via/h"
+
+Div(Class("card"),
+    H2(Text("Title")),
+    P(Textf("Count: %d", count)),
+    Button(Text("Click"), action.OnClick()),
+)
+```
+
+## Text Nodes
+
+| Function | Description |
+|----------|-------------|
+| `Text(s)` | Escaped text node |
+| `Textf(fmt, args...)` | Escaped text with `fmt.Sprintf` |
+| `Raw(s)` | Unescaped raw HTML — use for trusted content like SVG |
+| `Rawf(fmt, args...)` | Unescaped raw HTML with `fmt.Sprintf` |
+
+## Elements
+
+Every element function takes `...H` children (elements, attributes, and text nodes mixed together) except `Style(v string)` and `Title(v string)` which take a single string.
+
+### Document structure
+
+`HTML`, `Head`, `Body`, `Main`, `Header`, `Footer`, `Section`, `Article`, `Aside`, `Nav`, `Div`, `Span`
+
+### Headings
+
+`H1`, `H2`, `H3`, `H4`, `H5`, `H6`
+
+### Text
+
+`P`, `A`, `Strong`, `Em`, `B`, `I`, `U`, `S`, `Small`, `Mark`, `Del`, `Ins`, `Sub`, `Sup`, `Abbr`, `Cite`, `Code`, `Pre`, `Samp`, `Kbd`, `Var`, `Q`, `BlockQuote`, `Dfn`, `Wbr`, `Br`, `Hr`
+
+### Forms
+
+`Form`, `Input`, `Textarea`, `Select`, `Option`, `OptGroup`, `Button`, `Label`, `FieldSet`, `Legend`, `DataList`, `Meter`, `Progress`
+
+### Tables
+
+`Table`, `THead`, `TBody`, `TFoot`, `Tr`, `Th`, `Td`, `Caption`, `Col`, `ColGroup`
+
+### Lists
+
+`Ul`, `Ol`, `Li`, `Dl`, `Dt`, `Dd`
+
+### Media
+
+`Img`, `Audio`, `Video`, `Source`, `Picture`, `Canvas`, `IFrame`, `Embed`, `Object`
+
+### Other
+
+`Details`, `Summary`, `Dialog`, `Template`, `NoScript`, `Figure`, `FigCaption`, `Address`, `Time`, `Base`, `Link`, `Meta`, `Script`, `Area`
+
+### Special signatures
+
+| Function | Signature | Notes |
+|----------|-----------|-------|
+| `Style(v)` | `func Style(v string) H` | Inline `style` attribute, not a container element |
+| `StyleEl(children...)` | `func StyleEl(children ...H) H` | The `<style>` element as a container |
+| `Title(v)` | `func Title(v string) H` | Sets `<title>` text |
+
+## Attributes
+
+### Generic
+
+```go
+Attr("name", "value")     // name="value"
+Attr("disabled")           // boolean attribute (no value)
+```
+
+`Attr` with no value produces a boolean attribute. With one value, it produces a name-value pair. More than one value panics.
+
+### Named helpers
+
+| Function | HTML output |
+|----------|-------------|
+| `ID(v)` | `id="v"` |
+| `Class(v)` | `class="v"` |
+| `Href(v)` | `href="v"` |
+| `Src(v)` | `src="v"` |
+| `Type(v)` | `type="v"` |
+| `Value(v)` | `value="v"` |
+| `Placeholder(v)` | `placeholder="v"` |
+| `Rel(v)` | `rel="v"` |
+| `Role(v)` | `role="v"` |
+| `Data(name, v)` | `data-name="v"` (auto-prefixes `data-`) |
+
+## Conditional Rendering
+
+```go
+h.If(showError, h.P(h.Class("error"), h.Text("Something went wrong")))
+```
+
+Returns the node when `true`, `nil` (renders nothing) when `false`.
+
+## Datastar Helpers
+
+These produce attributes used by Datastar for client-side reactivity.
+
+| Function | Output | Description |
+|----------|--------|-------------|
+| `DataInit(expr)` | `data-init="expr"` | Initialize client-side state |
+| `DataEffect(expr)` | `data-effect="expr"` | Reactive side effect expression |
+| `DataIgnoreMorph()` | `data-ignore-morph` | Skip this element during DOM morph. See [SPA Navigation](routing-and-navigation.md#dataignoremorph) |
+| `DataViewTransition(name)` | `style="view-transition-name: name"` | Animate element across SPA navigations. See [View Transitions](routing-and-navigation.md#view-transitions) |
+
+> `DataViewTransition` sets the entire `style` attribute. If you also need other inline styles, include `view-transition-name` directly in a `Style()` call.
+
+## Utilities
+
+### HTML5
+
+Full HTML5 document template:
+
+```go
+h.HTML5(h.HTML5Props{
+    Title:       "My Page",
+    Description: "Page description",
+    Language:    "en",
+    Head:        []h.H{h.Link(h.Rel("stylesheet"), h.Href("/style.css"))},
+    Body:        []h.H{h.Div(h.Text("Hello"))},
+})
+```
+
+Via uses this internally to render the initial page document. You typically don't need it directly.
+
+### JoinAttrs
+
+Joins attribute values from child nodes by spaces:
+
+```go
+h.JoinAttrs("class", h.Class("card"), h.Class("active"))
+// → class="card active"
+```

docs/project-structure.md

@@ -0,0 +1,164 @@
+# Project Structure
+
+Via's closure-based page model pulls signals, actions, and views into a single scope — similar to Svelte's single-file components. This works well at every scale, but the way you organize files should evolve as your app grows.
+
+## Stage 1: Everything in main.go
+
+For small apps and prototypes, keep everything in `main.go`. This is the right choice when your app is under ~150 lines or has a single page.
+
+Within the file, follow this ordering convention inside each page:
+
+```go
+v.Page("/", func(c *via.Context) {
+    // State — plain Go variables and signals
+    count := 0
+    step := c.Signal(1)
+
+    // Actions — event handlers that mutate state
+    increment := c.Action(func() {
+        count += step.Int()
+        c.Sync()
+    })
+
+    // View — returns the HTML tree
+    c.View(func() h.H {
+        return h.Div(
+            h.P(h.Textf("Count: %d", count)),
+            h.Button(h.Text("+"), increment.OnClick()),
+        )
+    })
+})
+```
+
+State → signals → actions → view. This reads top-to-bottom and matches the data flow: state is declared, actions mutate it, the view renders it.
+
+The [counter](../internal/examples/counter/main.go) and [greeter](../internal/examples/greeter/main.go) examples use this layout.
+
+## Stage 2: Page per file
+
+When `main.go` has multiple pages or exceeds ~150 lines, extract each page into its own file as a package-level function.
+
+`main.go` becomes the app skeleton — setup, configuration, routes, and start:
+
+```go
+package main
+
+import (
+    "github.com/ryanhamamura/via"
+    "github.com/ryanhamamura/via/h"
+)
+
+func main() {
+    v := via.New()
+    v.Config(via.Options{
+        DocumentTitle: "My App",
+    })
+
+    v.AppendToHead(
+        h.Link(h.Rel("stylesheet"), h.Href("/css/pico.css")),
+    )
+
+    v.Page("/", HomePage)
+    v.Page("/chat", ChatPage)
+
+    v.Start()
+}
+```
+
+Each page lives in its own file with a descriptive name:
+
+```go
+// home.go
+package main
+
+import (
+    "github.com/ryanhamamura/via"
+    "github.com/ryanhamamura/via/h"
+)
+
+func HomePage(c *via.Context) {
+    greeting := c.Signal("Hello")
+
+    c.View(func() h.H {
+        return h.Div(h.P(h.Text(greeting.String())))
+    })
+}
+```
+
+Components follow the same pattern — keep them in the page file if single-use, or extract to their own file if reused across pages. Middleware goes in the same file as the route group it protects, or in `middleware.go` if shared.
+
+```
+myapp/
+├── main.go         # skeleton + routes
+├── home.go         # func HomePage(c *via.Context)
+├── chat.go         # func ChatPage(c *via.Context)
+└── middleware.go    # shared middleware
+```
+
+## Stage 3: Co-located CSS and shared types
+
+As pages accumulate custom styling, CSS strings in Go become hard to maintain — no syntax highlighting, no linting. Extract them to `.css` files alongside the pages they belong to and use `//go:embed` to load them.
+
+```go
+// main.go
+package main
+
+import "embed"
+
+//go:embed chat.css
+var chatCSS string
+
+func main() {
+    v := via.New()
+
+    v.AppendToHead(
+        h.Link(h.Rel("stylesheet"), h.Href("https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css")),
+        h.StyleEl(h.Raw(chatCSS)),
+    )
+
+    // ...
+}
+```
+
+When multiple pages share the same structs, extract them to `types.go`. Framework-agnostic domain logic (helpers, dummy data, business rules) gets its own file too.
+
+```
+myapp/
+├── main.go         # skeleton + routes + global styles
+├── home.go
+├── chat.go
+├── chat.css        # //go:embed in main.go
+├── types.go        # shared types
+└── userdata.go     # helpers, dummy data
+```
+
+The [nats-chatroom](../internal/examples/nats-chatroom/) example demonstrates this layout.
+
+## CSS Approaches
+
+Via doesn't prescribe a CSS strategy. Two approaches work well:
+
+**CSS framework classes in Go code** — Use Pico, Tailwind, or similar. Classes go directly in the view via `h.Class()`. Good for rapid prototyping since there's nothing to extract.
+
+```go
+h.Div(h.Class("container"),
+    h.Button(h.Class("primary"), h.Text("Save")),
+)
+```
+
+**Co-located `.css` files with `//go:embed`** — Write plain CSS in a separate file, embed it, and inject via `AppendToHead`. You get syntax highlighting, linting, and clean separation.
+
+```go
+//go:embed chat.css
+var chatCSS string
+
+// in main():
+v.AppendToHead(h.StyleEl(h.Raw(chatCSS)))
+```
+
+Use a framework for quick prototypes and dashboards. Switch to co-located CSS files when you have significant custom styling or want tooling support.
+
+## Next Steps
+
+- [Getting Started](getting-started.md) — The core loop and configuration
+- [State and Interactivity](state-and-interactivity.md) — Signals, actions, components, validation

docs/pubsub-and-sessions.md

@@ -0,0 +1,251 @@
+# PubSub and Sessions
+
+Infrastructure for multi-user real-time communication and persistent state.
+
+## PubSub
+
+Via includes an embedded NATS server that starts automatically with `via.New()`. No external services required — pub/sub works out of the box.
+
+### Interface
+
+```go
+type PubSub interface {
+    Publish(subject string, data []byte) error
+    Subscribe(subject string, handler func(data []byte)) (Subscription, error)
+    Close() error
+}
+
+type Subscription interface {
+    Unsubscribe() error
+}
+```
+
+You can replace the default NATS with any backend implementing this interface via `Options.PubSub`.
+
+### Basic pub/sub
+
+```go
+// Subscribe to messages
+via.Subscribe(c, "chat.room.general", func(msg ChatMessage) {
+    messages = append(messages, msg)
+    c.Sync()
+})
+
+// Publish a message
+via.Publish(c, "chat.room.general", ChatMessage{
+    User:    username,
+    Message: text,
+    Time:    time.Now().UnixMilli(),
+})
+```
+
+The generic helpers `via.Publish[T]` and `via.Subscribe[T]` handle JSON marshaling/unmarshaling automatically. They are package-level functions (not methods) because Go doesn't support generic methods.
+
+Raw byte-level access is also available on the context:
+
+```go
+c.Publish("subject", []byte("raw data"))
+c.Subscribe("subject", func(data []byte) { /* ... */ })
+```
+
+### Auto-cleanup
+
+Subscriptions created via `c.Subscribe()` or `via.Subscribe()` are tracked on the context and automatically unsubscribed when:
+
+- The context is disposed (browser disconnects, tab closes)
+- SPA navigation moves to a different page
+
+You don't need to manually unsubscribe in normal usage.
+
+### Custom backend
+
+Replace the embedded NATS with your own PubSub implementation:
+
+```go
+v.Config(via.Options{
+    PubSub: myRedisBackend,
+})
+```
+
+This disables the embedded NATS server. The `NATSConn()` and `JetStream()` accessors will return nil.
+
+## JetStream
+
+NATS JetStream provides persistent, replayable message streams. Useful for chat history, event logs, or any scenario where new subscribers need to catch up on past messages.
+
+### Ensure a stream exists
+
+```go
+err := via.EnsureStream(v, via.StreamConfig{
+    Name:     "CHAT",
+    Subjects: []string{"chat.>"},
+    MaxMsgs:  1000,
+    MaxAge:   24 * time.Hour,
+})
+```
+
+| Field | Description |
+|-------|-------------|
+| `Name` | Stream name |
+| `Subjects` | NATS subjects to capture (supports wildcards: `>` matches all sub-levels) |
+| `MaxMsgs` | Maximum number of messages to retain |
+| `MaxAge` | Maximum age before messages are discarded |
+
+Call `EnsureStream` during app initialization, before `v.Start()`.
+
+### Replay history
+
+Retrieve recent messages from a stream:
+
+```go
+messages, err := via.ReplayHistory[ChatMessage](v, "chat.room.general", 50)
+```
+
+Returns up to the last `limit` messages on the subject, deserialized as `T`. Use this when a new user joins and needs to see recent history.
+
+### Direct NATS access
+
+For advanced use cases, access the NATS connection and JetStream context directly:
+
+```go
+nc := v.NATSConn()       // *nats.Conn, nil if custom PubSub
+js := v.JetStream()      // nats.JetStreamContext, nil if custom PubSub
+```
+
+### PubSub accessor
+
+Access the configured PubSub backend from the `V` instance:
+
+```go
+ps := v.PubSub() // via.PubSub interface, nil if none configured
+```
+
+## Sessions
+
+Via uses [SCS](https://github.com/alexedwards/scs) for cookie-based session management.
+
+### Setup with SQLite
+
+```go
+db, _ := sql.Open("sqlite3", "app.db")
+
+sm, _ := via.NewSQLiteSessionManager(db)
+sm.Lifetime = 24 * time.Hour
+sm.Cookie.SameSite = http.SameSiteLaxMode
+
+v.Config(via.Options{SessionManager: sm})
+```
+
+`NewSQLiteSessionManager` creates the `sessions` table and index if they don't exist. The returned `*scs.SessionManager` can be configured further (lifetime, cookie settings) before passing to `Config`.
+
+A default in-memory session manager is always available, even without explicit configuration. Use `NewSQLiteSessionManager` when you need sessions to survive server restarts.
+
+### Session API
+
+Access the session from any context:
+
+```go
+s := c.Session()
+```
+
+**Getters:**
+
+| Method | Return type |
+|--------|-------------|
+| `s.Get(key)` | `any` |
+| `s.GetString(key)` | `string` |
+| `s.GetInt(key)` | `int` |
+| `s.GetBool(key)` | `bool` |
+| `s.GetFloat64(key)` | `float64` |
+| `s.GetTime(key)` | `time.Time` |
+| `s.GetBytes(key)` | `[]byte` |
+
+**Pop** (get and delete — useful for flash messages):
+
+| Method | Return type |
+|--------|-------------|
+| `s.Pop(key)` | `any` |
+| `s.PopString(key)` | `string` |
+| `s.PopInt(key)` | `int` |
+| `s.PopBool(key)` | `bool` |
+| `s.PopFloat64(key)` | `float64` |
+| `s.PopTime(key)` | `time.Time` |
+| `s.PopBytes(key)` | `[]byte` |
+
+**Mutators:**
+
+| Method | Description |
+|--------|-------------|
+| `s.Set(key, val)` | Store a value |
+| `s.Delete(key)` | Remove a single key |
+| `s.Clear()` | Remove all session data |
+| `s.Destroy()` | Destroy the entire session (for logout) |
+| `s.RenewToken()` | Regenerate session ID (prevents session fixation — call after login) |
+
+**Introspection:**
+
+| Method | Description |
+|--------|-------------|
+| `s.Exists(key)` | True if key exists |
+| `s.Keys()` | All keys in the session |
+| `s.ID()` | Session token (cookie value) |
+
+All getters return zero values if the key doesn't exist or the session manager is nil.
+
+### Auth pattern
+
+A common login/logout flow using sessions and middleware:
+
+```go
+// Middleware
+func authRequired(c *via.Context, next func()) {
+    if c.Session().GetString("username") == "" {
+        c.Session().Set("flash", "Please log in first")
+        c.RedirectView("/login")
+        return
+    }
+    next()
+}
+
+// Login page
+v.Page("/login", func(c *via.Context) {
+    user := c.Signal("")
+    pass := c.Signal("")
+    flash := c.Session().PopString("flash")
+
+    login := c.Action(func() {
+        if authenticate(user.String(), pass.String()) {
+            c.Session().RenewToken()
+            c.Session().Set("username", user.String())
+            c.Redirect("/dashboard")
+        } else {
+            flash = "Invalid credentials"
+            c.Sync()
+        }
+    })
+
+    c.View(func() h.H {
+        return h.Form(login.OnSubmit(),
+            h.If(flash != "", h.P(h.Text(flash))),
+            h.Input(h.Type("text"), user.Bind(), h.Placeholder("Username")),
+            h.Input(h.Type("password"), pass.Bind(), h.Placeholder("Password")),
+            h.Button(h.Type("submit"), h.Text("Log In")),
+        )
+    })
+})
+
+// Protected pages
+protected := v.Group("", authRequired)
+protected.Page("/dashboard", dashboardHandler)
+
+// Logout action (inside a protected page)
+logout := c.Action(func() {
+    c.Session().Destroy()
+    c.Redirect("/login")
+})
+```
+
+Key points:
+- Call `RenewToken()` after login to prevent session fixation.
+- Use `PopString` for flash messages — they're read once then removed.
+- Use `RedirectView` in middleware, `Redirect` in actions. See the [gotcha in routing](routing-and-navigation.md#middleware).

docs/routing-and-navigation.md

@@ -0,0 +1,222 @@
+# Routing and Navigation
+
+Multi-page app structure, middleware, and Via's SPA navigation system.
+
+## Pages
+
+Register a page with a route pattern and an init function:
+
+```go
+v.Page("/", func(c *via.Context) {
+    c.View(func() h.H {
+        return h.H1(h.Text("Home"))
+    })
+})
+```
+
+Routes use Go's standard `net/http.ServeMux` patterns. Via registers each page as a `GET` handler.
+
+> **Gotcha:** Via runs every page init function at registration time (in a `defer/recover` block) to catch panics early. If your init function panics — e.g. by forgetting `c.View()` — the app crashes at startup, not at request time.
+
+## Path Parameters
+
+Use `{param}` syntax in route patterns:
+
+```go
+v.Page("/users/{id}/posts/{post_id}", func(c *via.Context) {
+    userID := c.GetPathParam("id")
+    postID := c.GetPathParam("post_id")
+
+    c.View(func() h.H {
+        return h.P(h.Textf("User %s, Post %s", userID, postID))
+    })
+})
+```
+
+`GetPathParam` returns an empty string if the parameter doesn't exist.
+
+## Route Groups
+
+Group pages under a shared prefix with shared middleware:
+
+```go
+admin := v.Group("/admin", authRequired)
+admin.Page("/dashboard", dashboardHandler) // route: /admin/dashboard
+admin.Page("/settings", settingsHandler)   // route: /admin/settings
+```
+
+### Nesting
+
+Groups nest — the child inherits the parent's prefix and middleware:
+
+```go
+admin := v.Group("/admin", authRequired)
+admin.Use(auditLog) // add middleware after creation
+
+superAdmin := admin.Group("/super", superAdminOnly)
+superAdmin.Page("/nuke", nukeHandler) // route: /admin/super/nuke
+// middleware order: global → authRequired → auditLog → superAdminOnly → handler
+```
+
+### Empty prefix
+
+Use an empty prefix when you need shared middleware without a path prefix:
+
+```go
+protected := v.Group("", authRequired)
+protected.Page("/dashboard", dashboardHandler) // route: /dashboard
+protected.Page("/profile", profileHandler)     // route: /profile
+```
+
+## Middleware
+
+```go
+type Middleware func(c *Context, next func())
+```
+
+Call `next()` to continue the chain. Return without calling `next()` to abort — but set a view first.
+
+```go
+func authRequired(c *via.Context, next func()) {
+    if c.Session().GetString("username") == "" {
+        c.Session().Set("flash", "Please log in")
+        c.RedirectView("/login")
+        return // don't call next — chain is aborted
+    }
+    next()
+}
+```
+
+> **Gotcha:** Use `c.RedirectView()` in middleware, not `c.Redirect()`. The SSE connection isn't open yet during the initial page load, so `Redirect()` (which sends a patch over SSE) won't work. `RedirectView()` sets the view to one that triggers a redirect once SSE connects.
+
+### Three levels
+
+| Level | Registration | Scope |
+|-------|-------------|-------|
+| Global | `v.Use(mw...)` | Every page |
+| Group | `v.Group(prefix, mw...)` or `g.Use(mw...)` | Pages in the group |
+| Action | `c.Action(fn, via.WithMiddleware(mw...))` | A single action endpoint |
+
+### Execution order
+
+Middleware runs in registration order: global first, then group, then the handler.
+
+```go
+v.Use(logger)                        // 1st
+admin := v.Group("/admin", auth)     // 2nd
+admin.Use(audit)                     // 3rd
+admin.Page("/x", handler)           // 4th
+// execution: logger → auth → audit → handler
+```
+
+Action-level middleware runs after CSRF validation and rate limiting, when the action endpoint is invoked.
+
+## SPA Navigation
+
+Via intercepts same-origin link clicks and navigates without a full page reload. The SSE connection persists, and the new page's view is morphed into the DOM with a view transition.
+
+### How it works
+
+1. `navigate.js` (embedded in every page) intercepts clicks on `<a>` elements.
+2. For same-origin links, it POSTs to `/_navigate` with the context ID, CSRF token, and target URL.
+3. The server calls `c.Navigate()`, which:
+   - Resets page state (stops intervals, unsubscribes PubSub, clears signals/actions/fields)
+   - Runs the target page's init function (with middleware) on the **same context**
+   - Pushes the new view via SSE with a view transition
+   - Updates the browser URL via `history.pushState()`
+
+### What gets cleaned up on navigate
+
+- Intervals stop (via `pageStopChan`)
+- PubSub subscriptions are unsubscribed
+- Signals, actions, and fields are cleared
+- The new page starts completely fresh
+
+The SSE connection and the context itself survive. This is what makes it an SPA — the existing stream is reused.
+
+### Layouts
+
+Define a layout to provide persistent chrome (nav bars, sidebars) that wraps every page:
+
+```go
+v.Layout(func(content func() h.H) h.H {
+    return h.Div(
+        h.Nav(
+            h.A(h.Href("/"), h.Text("Home")),
+            h.A(h.Href("/counter"), h.Text("Counter")),
+            h.A(h.Href("/clock"), h.Text("Clock")),
+        ),
+        h.Main(content()),
+    )
+})
+```
+
+The `content` parameter is the page's view function. During SPA navigation, the entire layout + content is re-rendered and morphed — Datastar's morph algorithm (idiomorph) efficiently updates only the changed parts, so the nav bar stays visually stable while the main content transitions.
+
+> **Gotcha:** Layout state does not persist across navigations in the way page state doesn't — the layout is re-rendered from scratch each time. If you need state that survives navigation (like a selected nav item), derive it from the current route rather than storing it in a variable.
+
+### View transitions
+
+Animate elements across page navigations using the browser View Transitions API:
+
+```go
+// On the home page:
+h.H1(h.Text("Home"), h.DataViewTransition("page-title"))
+
+// On the counter page:
+h.H1(h.Text("Counter"), h.DataViewTransition("page-title"))
+```
+
+Elements with matching `view-transition-name` values animate smoothly during SPA navigation. `DataViewTransition` sets the CSS `view-transition-name` as an inline `style` attribute. If the element also needs other inline styles, set `view-transition-name` directly in a `Style()` call instead.
+
+Via automatically includes the `<meta name="view-transition" content="same-origin">` tag to enable the API.
+
+### Opting out
+
+Add `data-via-no-boost` to links that should trigger a full page reload:
+
+```go
+h.A(h.Href("/"), h.Text("Full Reload"), h.Attr("data-via-no-boost"))
+```
+
+Links are also auto-ignored when:
+- They have a `target` attribute (e.g. `target="_blank"`)
+- Modifier keys are held (Ctrl, Meta, Shift, Alt)
+- The `href` starts with `#` or is cross-origin
+- The `href` is missing
+
+### Programmatic navigation
+
+Trigger SPA navigation from an action handler:
+
+```go
+goCounter := c.Action(func() {
+    c.Navigate("/counter", false)
+})
+```
+
+The second parameter controls history behavior: `false` for `pushState` (normal navigation), `true` for `replaceState` (back/forward).
+
+If the path doesn't match any registered route, `Navigate` falls back to `c.Redirect()` (full page navigation).
+
+### DataIgnoreMorph
+
+Prevent Datastar from overwriting an element during morph:
+
+```go
+h.Div(h.ID("toast-container"), h.DataIgnoreMorph())
+```
+
+The element and its subtree are skipped during DOM patches. Useful for elements with client-side state: a focused input, an animation, a third-party widget, or a toast notification container.
+
+## Custom HTTP Handlers
+
+Access the underlying mux for non-Via routes (APIs, webhooks, health checks):
+
+```go
+mux := v.HTTPServeMux()
+mux.HandleFunc("GET /api/health", healthHandler)
+mux.HandleFunc("POST /api/webhook", webhookHandler)
+```
+
+Register before `v.Start()`. These routes bypass Via's context/SSE system entirely.

docs/state-and-interactivity.md

@@ -0,0 +1,313 @@
+# State and Interactivity
+
+This is the core reactive model — signals, actions, views, components, and validation.
+
+## Context Lifecycle
+
+A `*Context` is created per browser visit. It holds all page state: signals, actions, fields, subscriptions, and the view function.
+
+```
+Browser hits page → new Context created → init function runs → HTML rendered
+                                                                    ↓
+                                        SSE connection opens ← browser loads page
+                                                ↓
+                        action fires → signals injected from browser → handler runs → Sync() → DOM patched
+```
+
+The context is disposed when the SSE connection closes (tab close, navigation away, network loss). A background reaper also cleans up contexts that never establish an SSE connection within `ContextTTL` (default 30s).
+
+During [SPA navigation](routing-and-navigation.md#spa-navigation), the context itself survives — only page-level state (signals, actions, fields, intervals, subscriptions) is reset. The SSE connection persists.
+
+## Signals
+
+Signals are reactive values synchronized between server and browser. Create one with an initial value:
+
+```go
+name := c.Signal("world")
+count := c.Signal(0)
+items := c.Signal([]string{"a", "b"})
+```
+
+### Reading values
+
+```go
+name.String()  // "world"
+count.Int()    // 0
+count.Bool()   // false (parses "true", "1", "yes", "on")
+```
+
+Signal values come from the browser. Before every action call, the browser sends all current signal values to the server. You always read the latest browser state inside action handlers.
+
+### Writing values
+
+```go
+name.SetValue("Via")
+c.SyncSignals()  // push only changed signals to browser
+// or
+c.Sync()  // re-render view AND push changed signals
+```
+
+`SetValue` marks the signal as changed. The change is not sent to the browser until you call `Sync()` or `SyncSignals()`.
+
+### Rendering in the view
+
+```go
+// Two-way binding on an input — browser edits update the signal
+h.Input(h.Type("text"), name.Bind())
+
+// Reactive text display — updates when the signal changes
+h.Span(name.Text())
+
+// Read value at render time — static until next Sync()
+h.P(h.Textf("Count: %d", count.Int()))
+```
+
+`Bind()` outputs a `data-bind` attribute for two-way binding. `Text()` outputs a `<span data-text="$signalID">` for reactive display.
+
+## Actions
+
+Actions are server-side event handlers. They run on the server when triggered by a browser event.
+
+```go
+submit := c.Action(func() {
+    // signals are already injected — read them here
+    fmt.Println(name.String())
+    count.SetValue(count.Int() + 1)
+    c.Sync()
+})
+```
+
+### Trigger methods
+
+Attach an action to a DOM event by calling a trigger method in the view:
+
+```go
+h.Button(h.Text("Submit"), submit.OnClick())
+h.Input(name.Bind(), submit.OnKeyDown("Enter"))
+h.Select(category.Bind(), filter.OnChange())
+h.Form(submit.OnSubmit())
+```
+
+Available triggers:
+
+| Method | Event | Notes |
+|--------|-------|-------|
+| `OnClick()` | `click` | |
+| `OnDblClick()` | `dblclick` | |
+| `OnChange()` | `change` | 200ms debounce |
+| `OnInput()` | `input` | No debounce |
+| `OnSubmit()` | `submit` | |
+| `OnKeyDown(key)` | `keydown` | Filtered by key name (e.g. `"Enter"`, `"Escape"`) |
+| `OnFocus()` | `focus` | |
+| `OnBlur()` | `blur` | |
+| `OnMouseEnter()` | `mouseenter` | |
+| `OnMouseLeave()` | `mouseleave` | |
+| `OnScroll()` | `scroll` | |
+
+### Trigger options
+
+Every trigger method accepts `ActionTriggerOption` values:
+
+```go
+// Set a signal value before the action fires
+submit.OnClick(via.WithSignal(mode, "delete"))
+submit.OnClick(via.WithSignalInt(page, 3))
+
+// Listen on window instead of the element
+submit.OnKeyDown("Escape", via.WithWindow())
+
+// Prevent browser default behavior
+submit.OnKeyDown("ArrowDown", via.WithPreventDefault())
+```
+
+### Multi-key dispatch
+
+`OnKeyDownMap` binds multiple keys to different actions in a single attribute:
+
+```go
+via.OnKeyDownMap(
+    via.KeyBind("w", move, via.WithSignal(dir, "up")),
+    via.KeyBind("s", move, via.WithSignal(dir, "down")),
+    via.KeyBind("ArrowUp", move, via.WithSignal(dir, "up"), via.WithPreventDefault()),
+    via.KeyBind("ArrowDown", move, via.WithSignal(dir, "down"), via.WithPreventDefault()),
+)
+```
+
+This produces a single `data-on:keydown__window` attribute. Place it on any element in the view.
+
+### Action options
+
+```go
+// Per-action rate limiting (overrides the context-level default)
+c.Action(handler, via.WithRateLimit(5, 10))
+
+// Per-action middleware (runs after CSRF and rate-limit checks)
+c.Action(handler, via.WithMiddleware(requireAdmin))
+```
+
+## Views and Sync
+
+Every page handler must call `c.View()` to define the UI:
+
+```go
+c.View(func() h.H {
+    return h.Div(
+        h.P(h.Textf("Hello, %s!", name.String())),
+    )
+})
+```
+
+> **Gotcha:** If you forget `c.View()`, the app panics at startup during route registration — not at request time.
+
+The view function is re-evaluated on every `c.Sync()`. The resulting HTML is pushed to the browser via SSE, where Datastar morphs the DOM.
+
+### Sync variants
+
+| Method | What it sends |
+|--------|---------------|
+| `c.Sync()` | Re-renders the view HTML **and** pushes changed signals |
+| `c.SyncSignals()` | Pushes only changed signals, no view re-render |
+| `c.SyncElements(elem...)` | Pushes specific HTML elements to merge into the DOM. Each element **must have an ID** matching an existing DOM element |
+| `c.ExecScript(js)` | Sends JavaScript for the browser to execute (auto-removed after execution) |
+
+Use `SyncSignals()` when only signal values changed and the view structure is the same. Use `SyncElements()` for targeted updates without re-rendering the entire view. Use `ExecScript()` to interact with client-side libraries (e.g. pushing data to a chart).
+
+## Components
+
+Extract reusable UI with `c.Component()`:
+
+```go
+func counterFn(c *via.Context) {
+    count := 0
+    step := c.Signal(1)
+
+    increment := c.Action(func() {
+        count += step.Int()
+        c.Sync()
+    })
+
+    c.View(func() h.H {
+        return h.Div(
+            h.P(h.Textf("Count: %d", count)),
+            h.Input(h.Type("number"), step.Bind()),
+            h.Button(h.Text("+"), increment.OnClick()),
+        )
+    })
+}
+
+// In a page:
+v.Page("/", func(c *via.Context) {
+    counter1 := c.Component(counterFn)
+    counter2 := c.Component(counterFn)
+
+    c.View(func() h.H {
+        return h.Div(
+            h.H2(h.Text("Counter 1")), counter1(),
+            h.H2(h.Text("Counter 2")), counter2(),
+        )
+    })
+})
+```
+
+Each component instance gets its own closure state, but signals, actions, and fields are registered on the parent page context. Components share the parent's SSE stream — `c.Sync()` from a component re-renders the entire page view.
+
+## Fields and Validation
+
+Fields are signals with validation rules. Use them for form inputs:
+
+```go
+username := c.Field("", via.Required(), via.MinLen(3), via.MaxLen(20))
+email := c.Field("", via.Required(), via.Email())
+age := c.Field("", via.Required(), via.Min(13), via.Max(120))
+website := c.Field("", via.Pattern(`^https?://`, "Must start with http:// or https://"))
+```
+
+### Built-in rules
+
+| Rule | Description |
+|------|-------------|
+| `Required(msg...)` | Rejects empty/whitespace-only values |
+| `MinLen(n, msg...)` | Minimum character count (Unicode-aware) |
+| `MaxLen(n, msg...)` | Maximum character count (Unicode-aware) |
+| `Min(n, msg...)` | Minimum numeric value (parsed as int) |
+| `Max(n, msg...)` | Maximum numeric value (parsed as int) |
+| `Email(msg...)` | Email format regex |
+| `Pattern(re, msg...)` | Custom regex |
+| `Custom(fn)` | `func(string) error` — return non-nil to fail |
+
+All rules accept an optional custom error message as the last argument.
+
+### Using fields in views and actions
+
+```go
+submit := c.Action(func() {
+    if !c.ValidateAll() {
+        c.Sync()
+        return
+    }
+    // Server-side validation
+    if userExists(username.String()) {
+        username.AddError("Username taken")
+        c.Sync()
+        return
+    }
+    createUser(username.String(), email.String())
+    c.ResetFields()
+    c.Sync()
+})
+
+c.View(func() h.H {
+    return h.Form(submit.OnSubmit(),
+        h.Input(h.Type("text"), username.Bind(), h.Placeholder("Username")),
+        h.If(username.HasError(), h.Small(h.Text(username.FirstError()))),
+
+        h.Input(h.Type("email"), email.Bind(), h.Placeholder("Email")),
+        h.If(email.HasError(), h.Small(h.Text(email.FirstError()))),
+
+        h.Button(h.Type("submit"), h.Text("Sign Up")),
+    )
+})
+```
+
+| Method | Description |
+|--------|-------------|
+| `field.Validate()` | Run rules, return true if all pass |
+| `field.HasError()` | True if any validation errors exist |
+| `field.FirstError()` | First error message, or `""` |
+| `field.Errors()` | All error messages |
+| `field.AddError(msg)` | Add a custom server-side error |
+| `field.ClearErrors()` | Remove all errors |
+| `field.Reset()` | Restore initial value and clear errors |
+| `c.ValidateAll(fields...)` | Validate given fields (or all if none specified). Does not short-circuit — all fields get validated so all errors are populated |
+| `c.ResetFields(fields...)` | Reset given fields (or all if none specified) |
+
+Fields embed `*signal`, so `Bind()`, `Text()`, `String()`, `Int()`, `Bool()`, `SetValue()`, and `ID()` all work.
+
+## OnInterval
+
+Run a function at regular intervals, tied to the page lifecycle:
+
+```go
+stop := c.OnInterval(time.Second, func() {
+    now = time.Now()
+    c.Sync()
+})
+```
+
+- Starts immediately — no separate start call needed.
+- Returns a `func()` that stops the interval (idempotent).
+- Automatically stops on context disposal (tab close) or SPA navigation away.
+- Call `c.Sync()` inside the handler to push updates to the browser.
+
+## Navigation Helpers
+
+| Method | Effect |
+|--------|--------|
+| `c.Redirect(url)` | Full page navigation. Disposes the context, browser loads a new page |
+| `c.Redirectf(fmt, args...)` | `Redirect` with `fmt.Sprintf` |
+| `c.RedirectView(url)` | Sets the view to trigger a redirect on SSE connect. Use in [middleware](routing-and-navigation.md#middleware) to abort the chain and redirect |
+| `c.ReplaceURL(url)` | Updates the browser URL bar without navigation. Useful for reflecting state in query params |
+| `c.ReplaceURLf(fmt, args...)` | `ReplaceURL` with `fmt.Sprintf` |
+| `c.Navigate(path, popstate)` | [SPA navigation](routing-and-navigation.md#spa-navigation). Resets page state, runs the target page handler on the same context, pushes the new view with a view transition |
+
+> **Gotcha:** In middleware, use `c.RedirectView()`, not `c.Redirect()`. `Redirect` sends a patch over SSE, but the SSE connection isn't established yet during the initial page load.

internal/examples/nats-chatroom/chat.css

@@ -0,0 +1,153 @@
+body { margin: 0; }
+
+/* Layout navbar */
+.app-nav {
+	display: flex;
+	align-items: center;
+	gap: 1rem;
+	padding: 0.5rem 1rem;
+	background: var(--pico-card-background-color);
+	border-bottom: 1px solid var(--pico-muted-border-color);
+}
+.app-nav .brand {
+	font-weight: 700;
+	text-decoration: none;
+	margin-right: auto;
+}
+.nav-links {
+	display: flex;
+	gap: 1rem;
+}
+.nav-links a {
+	text-decoration: none;
+	font-size: 0.875rem;
+}
+
+/* Chat page */
+.chat-page {
+	display: flex;
+	flex-direction: column;
+	height: calc(100vh - 53px);
+}
+nav[role="tab-control"] ul li a[aria-current="page"] {
+	background-color: var(--pico-primary-background);
+	color: var(--pico-primary-inverse);
+	border-bottom: 2px solid var(--pico-primary);
+}
+.chat-message { display: flex; gap: 0.75rem; margin-bottom: 0.5rem; }
+.avatar {
+	width: 2rem;
+	height: 2rem;
+	border-radius: 50%;
+	background: var(--pico-muted-border-color);
+	display: grid;
+	place-items: center;
+	font-size: 1.5rem;
+	flex-shrink: 0;
+}
+.avatar-lg {
+	width: 3rem;
+	height: 3rem;
+	font-size: 2rem;
+}
+.bubble { flex: 1; }
+.bubble p { margin: 0; }
+.chat-history {
+	flex: 1;
+	overflow-y: auto;
+	padding: 1rem;
+	padding-bottom: calc(88px + env(safe-area-inset-bottom));
+}
+.chat-input {
+	position: fixed;
+	left: 0;
+	right: 0;
+	bottom: 0;
+	background: var(--pico-background-color);
+	display: flex;
+	align-items: center;
+	gap: 0.75rem;
+	padding: 0.75rem 1rem calc(0.75rem + env(safe-area-inset-bottom));
+	border-top: 1px solid var(--pico-muted-border-color);
+}
+.chat-input fieldset {
+	flex: 1;
+	margin: 0;
+}
+
+/* NATS badge with status dot */
+.nats-badge {
+	background: #27AAE1;
+	color: white;
+	padding: 0.25rem 0.5rem;
+	border-radius: 4px;
+	font-size: 0.75rem;
+	margin-left: auto;
+	display: flex;
+	align-items: center;
+	gap: 0.375rem;
+}
+.status-dot {
+	width: 8px;
+	height: 8px;
+	border-radius: 50%;
+	background: #4ade80;
+	animation: pulse 2s ease-in-out infinite;
+}
+@keyframes pulse {
+	0%, 100% { opacity: 1; }
+	50% { opacity: 0.4; }
+}
+
+/* Profile page */
+.profile-page {
+	max-width: 480px;
+	margin: 0 auto;
+	padding: 2rem 1rem;
+}
+.profile-preview {
+	display: flex;
+	align-items: center;
+	gap: 0.75rem;
+	margin-bottom: 1.5rem;
+	padding: 1rem;
+	background: var(--pico-card-background-color);
+	border-radius: 8px;
+}
+.preview-name {
+	font-size: 1.125rem;
+	font-weight: 600;
+}
+.profile-form label {
+	display: block;
+	margin-bottom: 0.5rem;
+}
+.emoji-grid {
+	display: grid;
+	grid-template-columns: repeat(10, 1fr);
+	gap: 0.25rem;
+	margin-bottom: 1.5rem;
+}
+.emoji-option {
+	padding: 0.375rem;
+	font-size: 1.25rem;
+	border: 2px solid transparent;
+	border-radius: 8px;
+	background: none;
+	cursor: pointer;
+	text-align: center;
+}
+.emoji-option:hover {
+	background: var(--pico-muted-border-color);
+}
+.emoji-selected {
+	border-color: var(--pico-primary);
+	background: var(--pico-primary-focus);
+}
+.profile-actions {
+	display: flex;
+	gap: 0.75rem;
+}
+.field-error {
+	color: var(--pico-del-color);
+}

internal/examples/nats-chatroom/chat.go

@@ -0,0 +1,148 @@
+package main
+
+import (
+	"sync"
+	"time"
+
+	"github.com/ryanhamamura/via"
+	"github.com/ryanhamamura/via/h"
+)
+
+var (
+	WithSignal = via.WithSignal
+)
+
+func ChatPage(c *via.Context) {
+	currentUser := UserInfo{
+		Name:  c.Session().GetString(SessionKeyUsername),
+		Emoji: c.Session().GetString(SessionKeyEmoji),
+	}
+
+	roomSignal := c.Signal("Go")
+	statement := c.Signal("")
+
+	var messages []ChatMessage
+	var messagesMu sync.Mutex
+	currentRoom := "Go"
+
+	var currentSub via.Subscription
+
+	subscribeToRoom := func(room string) {
+		if currentSub != nil {
+			currentSub.Unsubscribe()
+		}
+
+		subject := "chat.room." + room
+
+		if hist, err := via.ReplayHistory[ChatMessage](v, subject, 50); err == nil {
+			messages = hist
+		}
+
+		sub, _ := via.Subscribe(c, subject, func(msg ChatMessage) {
+			messagesMu.Lock()
+			messages = append(messages, msg)
+			if len(messages) > 50 {
+				messages = messages[len(messages)-50:]
+			}
+			messagesMu.Unlock()
+			c.Sync()
+		})
+		currentSub = sub
+		currentRoom = room
+	}
+
+	subscribeToRoom("Go")
+
+	// Heartbeat — keeps connected indicator alive
+	connected := true
+	c.OnInterval(30*time.Second, func() {
+		connected = true
+		c.Sync()
+	})
+
+	switchRoom := c.Action(func() {
+		newRoom := roomSignal.String()
+		if newRoom != currentRoom {
+			messagesMu.Lock()
+			messages = nil
+			messagesMu.Unlock()
+			subscribeToRoom(newRoom)
+			c.Sync()
+		}
+	})
+
+	say := c.Action(func() {
+		msg := statement.String()
+		if msg == "" {
+			msg = randomDevQuote()
+		}
+		statement.SetValue("")
+
+		via.Publish(c, "chat.room."+currentRoom, ChatMessage{
+			User:    currentUser,
+			Message: msg,
+			Time:    time.Now().UnixMilli(),
+		})
+	})
+
+	c.View(func() h.H {
+		var tabs []h.H
+		for _, name := range roomNames {
+			isCurrent := name == currentRoom
+			tabs = append(tabs, h.Li(
+				h.A(
+					h.If(isCurrent, h.Attr("aria-current", "page")),
+					h.Text(name),
+					switchRoom.OnClick(WithSignal(roomSignal, name)),
+				),
+			))
+		}
+
+		messagesMu.Lock()
+		chatHistoryChildren := []h.H{
+			h.Class("chat-history"),
+			h.Script(h.Raw(`new MutationObserver(()=>scrollChatToBottom()).observe(document.querySelector('.chat-history'), {childList:true})`)),
+		}
+		for _, msg := range messages {
+			chatHistoryChildren = append(chatHistoryChildren,
+				h.Div(h.Class("chat-message"),
+					h.Div(h.Class("avatar"), h.Attr("title", msg.User.Name), h.Text(msg.User.Emoji)),
+					h.Div(h.Class("bubble"),
+						h.P(h.Text(msg.Message)),
+					),
+				),
+			)
+		}
+		messagesMu.Unlock()
+
+		_ = connected
+
+		return h.Div(h.Class("chat-page"),
+			h.Nav(
+				h.Attr("role", "tab-control"),
+				h.Ul(tabs...),
+				h.Span(h.Class("nats-badge"),
+					h.Span(h.Class("status-dot")),
+					h.Text("NATS"),
+				),
+			),
+			h.Div(chatHistoryChildren...),
+			h.Div(
+				h.Class("chat-input"),
+				h.DataIgnoreMorph(),
+				currentUser.Avatar(),
+				h.FieldSet(
+					h.Attr("role", "group"),
+					h.Input(
+						h.Type("text"),
+						h.Placeholder(currentUser.Name+" says..."),
+						statement.Bind(),
+						h.Attr("autofocus"),
+						say.OnKeyDown("Enter"),
+					),
+					h.Button(h.Text("Send"), say.OnClick()),
+				),
+			),
+		)
+	})
+}

internal/examples/nats-chatroom/main.go

@@ -1,40 +1,21 @@
 package main
 
 import (
+	_ "embed"
 	"log"
-	"math/rand"
-	"sync"
 	"time"
 
 	"github.com/ryanhamamura/via"
 	"github.com/ryanhamamura/via/h"
 )
 
-var (
-	WithSignal = via.WithSignal
-)
+//go:embed chat.css
+var chatCSS string
 
-// ChatMessage represents a message in a chat room
-type ChatMessage struct {
-	User    UserInfo `json:"user"`
-	Message string   `json:"message"`
-	Time    int64    `json:"time"`
-}
-
-// UserInfo identifies a chat participant
-type UserInfo struct {
-	Name  string `json:"name"`
-	Emoji string `json:"emoji"`
-}
-
-func (u *UserInfo) Avatar() h.H {
-	return h.Div(h.Class("avatar"), h.Attr("title", u.Name), h.Text(u.Emoji))
-}
-
-var roomNames = []string{"Go", "Rust", "Python", "JavaScript", "Clojure"}
+var v *via.V
 
 func main() {
-	v := via.New()
+	v = via.New()
 	v.Config(via.Options{
 		DevMode:       true,
 		DocumentTitle: "NATS Chat",
@@ -54,62 +35,7 @@ func main() {
 
 	v.AppendToHead(
 		h.Link(h.Rel("stylesheet"), h.Href("https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css")),
-		h.StyleEl(h.Raw(`
-			body { margin: 0; }
-			main {
-				display: flex;
-				flex-direction: column;
-				height: 100vh;
-			}
-			nav[role="tab-control"] ul li a[aria-current="page"] {
-				background-color: var(--pico-primary-background);
-				color: var(--pico-primary-inverse);
-				border-bottom: 2px solid var(--pico-primary);
-			}
-			.chat-message { display: flex; gap: 0.75rem; margin-bottom: 0.5rem; }
-			.avatar {
-				width: 2rem;
-				height: 2rem;
-				border-radius: 50%;
-				background: var(--pico-muted-border-color);
-				display: grid;
-				place-items: center;
-				font-size: 1.5rem;
-				flex-shrink: 0;
-			}
-			.bubble { flex: 1; }
-			.bubble p { margin: 0; }
-			.chat-history {
-				flex: 1;
-				overflow-y: auto;
-				padding: 1rem;
-				padding-bottom: calc(88px + env(safe-area-inset-bottom));
-			}
-			.chat-input {
-				position: fixed;
-				left: 0;
-				right: 0;
-				bottom: 0;
-				background: var(--pico-background-color);
-				display: flex;
-				align-items: center;
-				gap: 0.75rem;
-				padding: 0.75rem 1rem calc(0.75rem + env(safe-area-inset-bottom));
-				border-top: 1px solid var(--pico-muted-border-color);
-			}
-			.chat-input fieldset {
-				flex: 1;
-				margin: 0;
-			}
-			.nats-badge {
-				background: #27AAE1;
-				color: white;
-				padding: 0.25rem 0.5rem;
-				border-radius: 4px;
-				font-size: 0.75rem;
-				margin-left: auto;
-			}
-		`)),
+		h.StyleEl(h.Raw(chatCSS)),
 		h.Script(h.Raw(`
 			function scrollChatToBottom() {
 				const chatHistory = document.querySelector('.chat-history');
@@ -118,156 +44,38 @@ func main() {
 		`)),
 	)
 
-	v.Page("/", func(c *via.Context) {
-		currentUser := randUser()
-		roomSignal := c.Signal("Go")
-		statement := c.Signal("")
-
-		var messages []ChatMessage
-		var messagesMu sync.Mutex
-		currentRoom := "Go"
-
-		var currentSub via.Subscription
-
-		subscribeToRoom := func(room string) {
-			if currentSub != nil {
-				currentSub.Unsubscribe()
-			}
-
-			subject := "chat.room." + room
-
-			// Replay history from JetStream
-			if hist, err := via.ReplayHistory[ChatMessage](v, subject, 50); err == nil {
-				messages = hist
-			}
-
-			sub, _ := via.Subscribe(c, subject, func(msg ChatMessage) {
-				messagesMu.Lock()
-				messages = append(messages, msg)
-				if len(messages) > 50 {
-					messages = messages[len(messages)-50:]
-				}
-				messagesMu.Unlock()
-				c.Sync()
-			})
-			currentSub = sub
-			currentRoom = room
-		}
-
-		subscribeToRoom("Go")
-
-		switchRoom := c.Action(func() {
-			newRoom := roomSignal.String()
-			if newRoom != currentRoom {
-				messagesMu.Lock()
-				messages = nil
-				messagesMu.Unlock()
-				subscribeToRoom(newRoom)
-				c.Sync()
-			}
-		})
-
-		say := c.Action(func() {
-			msg := statement.String()
-			if msg == "" {
-				msg = randomDevQuote()
-			}
-			statement.SetValue("")
-
-			via.Publish(c, "chat.room."+currentRoom, ChatMessage{
-				User:    currentUser,
-				Message: msg,
-				Time:    time.Now().UnixMilli(),
-			})
-		})
-
-		c.View(func() h.H {
-			var tabs []h.H
-			for _, name := range roomNames {
-				isCurrent := name == currentRoom
-				tabs = append(tabs, h.Li(
-					h.A(
-						h.If(isCurrent, h.Attr("aria-current", "page")),
-						h.Text(name),
-						switchRoom.OnClick(WithSignal(roomSignal, name)),
-					),
-				))
-			}
-
-			messagesMu.Lock()
-			chatHistoryChildren := []h.H{
-				h.Class("chat-history"),
-				h.Script(h.Raw(`new MutationObserver(()=>scrollChatToBottom()).observe(document.querySelector('.chat-history'), {childList:true})`)),
-			}
-			for _, msg := range messages {
-				chatHistoryChildren = append(chatHistoryChildren,
-					h.Div(h.Class("chat-message"),
-						h.Div(h.Class("avatar"), h.Attr("title", msg.User.Name), h.Text(msg.User.Emoji)),
-						h.Div(h.Class("bubble"),
-							h.P(h.Text(msg.Message)),
+	v.Layout(func(content func() h.H) h.H {
+		return h.Div(
+			h.Nav(h.Class("app-nav"),
+				h.A(h.Href("/"), h.Class("brand"), h.Text("NATS Chat")),
+				h.Div(h.Class("nav-links"),
+					h.A(h.Href("/"), h.Text("Chat")),
+					h.A(h.Href("/profile"), h.Text("Profile")),
 				),
 			),
-				)
-			}
-			messagesMu.Unlock()
-
-			return h.Main(h.Class("container"),
-				h.Nav(
-					h.Attr("role", "tab-control"),
-					h.Ul(tabs...),
-					h.Span(h.Class("nats-badge"), h.Text("NATS")),
-				),
-				h.Div(chatHistoryChildren...),
-				h.Div(
-					h.Class("chat-input"),
-					currentUser.Avatar(),
-					h.FieldSet(
-						h.Attr("role", "group"),
-						h.Input(
-							h.Type("text"),
-							h.Placeholder(currentUser.Name+" says..."),
-							statement.Bind(),
-							h.Attr("autofocus"),
-							say.OnKeyDown("Enter"),
-						),
-						h.Button(h.Text("Send"), say.OnClick()),
-					),
+			h.Main(h.Class("container"),
+				h.DataViewTransition("page-content"),
+				content(),
 			),
 		)
 	})
-	})
+
+	// Profile page — public, no auth required
+	v.Page("/profile", ProfilePage)
+
+	// Auth middleware — redirects to profile if no identity set
+	requireProfile := func(c *via.Context, next func()) {
+		if c.Session().GetString(SessionKeyUsername) == "" {
+			c.RedirectView("/profile")
+			return
+		}
+		next()
+	}
+
+	// Chat page — protected by profile middleware
+	protected := v.Group("", requireProfile)
+	protected.Page("/", ChatPage)
 
 	log.Println("Starting NATS chatroom on :7331 (embedded NATS server)")
 	v.Start()
 }
-
-func randUser() UserInfo {
-	adjectives := []string{"Happy", "Clever", "Brave", "Swift", "Gentle", "Wise", "Bold", "Calm", "Eager", "Fierce"}
-	animals := []string{"Panda", "Tiger", "Eagle", "Dolphin", "Fox", "Wolf", "Bear", "Hawk", "Otter", "Lion"}
-	emojis := []string{"🐼", "🐯", "🦅", "🐬", "🦊", "🐺", "🐻", "🦅", "🦦", "🦁"}
-
-	idx := rand.Intn(len(animals))
-	return UserInfo{
-		Name:  adjectives[rand.Intn(len(adjectives))] + " " + animals[idx],
-		Emoji: emojis[idx],
-	}
-}
-
-var quoteIdx = rand.Intn(len(devQuotes))
-var devQuotes = []string{
-	"Just use NATS.",
-	"Pub/sub all the things!",
-	"Messages are the new API.",
-	"JetStream for durability.",
-	"No more polling.",
-	"Event-driven architecture FTW.",
-	"Decouple everything.",
-	"NATS is fast.",
-	"Subjects are like topics.",
-	"Request-reply is cool.",
-}
-
-func randomDevQuote() string {
-	quoteIdx = (quoteIdx + 1) % len(devQuotes)
-	return devQuotes[quoteIdx]
-}

internal/examples/nats-chatroom/profile.go

@@ -0,0 +1,111 @@
+package main
+
+import (
+	"github.com/ryanhamamura/via"
+	"github.com/ryanhamamura/via/h"
+)
+
+func ProfilePage(c *via.Context) {
+	existingName := c.Session().GetString(SessionKeyUsername)
+	existingEmoji := c.Session().GetString(SessionKeyEmoji)
+	if existingEmoji == "" {
+		existingEmoji = emojiChoices[0]
+	}
+
+	nameField := c.Field(existingName,
+		via.Required("Display name is required"),
+		via.MinLen(2, "Must be at least 2 characters"),
+		via.MaxLen(20, "Must be at most 20 characters"),
+	)
+	selectedEmoji := c.Signal(existingEmoji)
+	previewName := c.Computed(func() string {
+		if name := nameField.String(); name != "" {
+			return name
+		}
+		return "Your Name"
+	})
+
+	saveToSession := func() bool {
+		if !c.ValidateAll() {
+			c.Sync()
+			return false
+		}
+		c.Session().Set(SessionKeyUsername, nameField.String())
+		c.Session().Set(SessionKeyEmoji, selectedEmoji.String())
+		return true
+	}
+
+	save := c.Action(func() {
+		saveToSession()
+	})
+
+	saveAndChat := c.Action(func() {
+		if saveToSession() {
+			c.Navigate("/", false)
+		}
+	})
+
+	c.View(func() h.H {
+		// Emoji grid
+		emojiGrid := []h.H{h.Class("emoji-grid")}
+		for _, emoji := range emojiChoices {
+			cls := "emoji-option"
+			if emoji == selectedEmoji.String() {
+				cls += " emoji-selected"
+			}
+			emojiGrid = append(emojiGrid,
+				h.Button(
+					h.Class(cls),
+					h.Type("button"),
+					h.Text(emoji),
+					save.OnClick(WithSignal(selectedEmoji, emoji)),
+				),
+			)
+		}
+
+		// Action buttons — "Start Chatting" only if editing is meaningful
+		actionButtons := []h.H{h.Class("profile-actions")}
+		if existingName != "" {
+			actionButtons = append(actionButtons,
+				h.Button(h.Text("Save"), save.OnClick(), h.Class("secondary")),
+			)
+		}
+		actionButtons = append(actionButtons,
+			h.Button(h.Text("Start Chatting"), saveAndChat.OnClick()),
+		)
+
+		return h.Div(h.Class("profile-page"),
+			h.H2(h.Text("Your Profile"), h.DataViewTransition("page-title")),
+
+			// Live preview
+			h.Div(h.Class("profile-preview"),
+				h.Div(h.Class("avatar avatar-lg"), h.Text(selectedEmoji.String())),
+				h.Span(h.Class("preview-name"), previewName.Text()),
+			),
+
+			h.Div(h.Class("profile-form"),
+				// Name field
+				h.Label(h.Text("Display Name"),
+					h.Input(
+						h.Type("text"),
+						h.Placeholder("Enter a display name"),
+						nameField.Bind(),
+						h.Attr("autofocus"),
+						saveAndChat.OnKeyDown("Enter"),
+						h.If(nameField.HasError(), h.Attr("aria-invalid", "true")),
+					),
+					h.If(nameField.HasError(),
+						h.Small(h.Class("field-error"), h.Text(nameField.FirstError())),
+					),
+				),
+
+				// Emoji picker
+				h.Label(h.Text("Choose an Avatar")),
+				h.Div(emojiGrid...),
+
+				// Actions
+				h.Div(actionButtons...),
+			),
+		)
+	})
+}

internal/examples/nats-chatroom/types.go

@@ -0,0 +1,30 @@
+package main
+
+import "github.com/ryanhamamura/via/h"
+
+const (
+	SessionKeyUsername = "username"
+	SessionKeyEmoji    = "emoji"
+)
+
+type ChatMessage struct {
+	User    UserInfo `json:"user"`
+	Message string   `json:"message"`
+	Time    int64    `json:"time"`
+}
+
+type UserInfo struct {
+	Name  string `json:"name"`
+	Emoji string `json:"emoji"`
+}
+
+func (u *UserInfo) Avatar() h.H {
+	return h.Div(h.Class("avatar"), h.Attr("title", u.Name), h.Text(u.Emoji))
+}
+
+var roomNames = []string{"Go", "Rust", "Python", "JavaScript", "Clojure"}
+
+var emojiChoices = []string{
+	"🐼", "🐯", "🦅", "🐬", "🦊", "🐺", "🐻", "🦦", "🦁", "🐸",
+	"🦄", "🐙", "🦀", "🐝", "🦋", "🐢", "🦉", "🐳", "🦈", "🐧",
+}

internal/examples/nats-chatroom/userdata.go

@@ -0,0 +1,22 @@
+package main
+
+import "math/rand"
+
+var quoteIdx = rand.Intn(len(devQuotes))
+var devQuotes = []string{
+	"Just use NATS.",
+	"Pub/sub all the things!",
+	"Messages are the new API.",
+	"JetStream for durability.",
+	"No more polling.",
+	"Event-driven architecture FTW.",
+	"Decouple everything.",
+	"NATS is fast.",
+	"Subjects are like topics.",
+	"Request-reply is cool.",
+}
+
+func randomDevQuote() string {
+	quoteIdx = (quoteIdx + 1) % len(devQuotes)
+	return devQuotes[quoteIdx]
+}

internal/examples/pubsub-crud/main.go

@@ -76,6 +76,12 @@ func main() {
 		titleSignal := c.Signal("")
 		urlSignal := c.Signal("")
 		targetIDSignal := c.Signal("")
+		saveLabel := c.Computed(func() string {
+			if targetIDSignal.String() != "" {
+				return "Update Bookmark"
+			}
+			return "Add Bookmark"
+		})
 
 		via.Subscribe(c, "bookmarks.events", func(evt CRUDEvent) {
 			if evt.UserID == userID {
@@ -205,11 +211,6 @@ func main() {
 			}
 			bookmarksMu.RUnlock()
 
-			saveLabel := "Add Bookmark"
-			if isEditing {
-				saveLabel = "Update Bookmark"
-			}
-
 			return h.Div(h.Class("min-h-screen bg-base-200"),
 				// Navbar
 				h.Div(h.Class("navbar bg-base-100 shadow-sm"),
@@ -225,7 +226,7 @@ func main() {
 					// Form card
 					h.Div(h.Class("card bg-base-100 shadow"),
 						h.Div(h.Class("card-body"),
-							h.H2(h.Class("card-title"), h.Text(saveLabel)),
+							h.H2(h.Class("card-title"), saveLabel.Text()),
 							h.Div(h.Class("flex flex-col gap-2"),
 								h.Input(h.Class("input input-bordered w-full"), h.Type("text"), h.Placeholder("Title"), titleSignal.Bind()),
 								h.Input(h.Class("input input-bordered w-full"), h.Type("text"), h.Placeholder("https://example.com"), urlSignal.Bind()),
@@ -233,7 +234,7 @@ func main() {
 									h.If(isEditing,
 										h.Button(h.Class("btn btn-ghost"), h.Text("Cancel"), cancelEdit.OnClick()),
 									),
-									h.Button(h.Class("btn btn-primary"), h.Text(saveLabel), save.OnClick()),
+									h.Button(h.Class("btn btn-primary"), saveLabel.Text(), save.OnClick()),
 								),
 							),
 						),

nats.go

@@ -56,7 +56,19 @@ func startDefaultNATS() (dn *defaultNATS, err error) {
 		os.RemoveAll(dataDir)
 		return nil, fmt.Errorf("start embedded nats: %w", err)
 	}
+	ready := make(chan struct{})
+	go func() {
 		ns.WaitForServer()
+		close(ready)
+	}()
+	select {
+	case <-ready:
+	case <-time.After(10 * time.Second):
+		ns.Close()
+		cancel()
+		os.RemoveAll(dataDir)
+		return nil, fmt.Errorf("embedded nats server did not start within 10s")
+	}
 
 	nc, err := ns.Client()
 	if err != nil {

nats_test.go

@@ -10,9 +10,24 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestPubSub_RoundTrip(t *testing.T) {
+// setupNATSTest creates a *V with an embedded NATS server.
+// Skips the test if NATS fails to start (e.g. port conflict in CI).
+func setupNATSTest(t *testing.T) *V {
+	t.Helper()
 	v := New()
-	defer v.Shutdown()
+	dn, err := getSharedNATS()
+	if err != nil {
+		v.Shutdown()
+		t.Skipf("embedded NATS unavailable: %v", err)
+	}
+	v.defaultNATS = dn
+	v.pubsub = &natsRef{dn: dn}
+	t.Cleanup(v.Shutdown)
+	return v
+}
+
+func TestPubSub_RoundTrip(t *testing.T) {
+	v := setupNATSTest(t)
 
 	var received []byte
 	done := make(chan struct{})
@@ -38,8 +53,7 @@ func TestPubSub_RoundTrip(t *testing.T) {
 }
 
 func TestPubSub_MultipleSubscribers(t *testing.T) {
-	v := New()
-	defer v.Shutdown()
+	v := setupNATSTest(t)
 
 	var mu sync.Mutex
 	var results []string
@@ -84,8 +98,7 @@ func TestPubSub_MultipleSubscribers(t *testing.T) {
 }
 
 func TestPubSub_SubscriptionCleanupOnDispose(t *testing.T) {
-	v := New()
-	defer v.Shutdown()
+	v := setupNATSTest(t)
 
 	c := newContext("cleanup-ctx", "/", v)
 	c.View(func() h.H { return h.Div() })
@@ -100,8 +113,7 @@ func TestPubSub_SubscriptionCleanupOnDispose(t *testing.T) {
 }
 
 func TestPubSub_ManualUnsubscribe(t *testing.T) {
-	v := New()
-	defer v.Shutdown()
+	v := setupNATSTest(t)
 
 	c := newContext("unsub-ctx", "/", v)
 	c.View(func() h.H { return h.Div() })
@@ -120,8 +132,7 @@ func TestPubSub_ManualUnsubscribe(t *testing.T) {
 }
 
 func TestPubSub_NoOpDuringPanicCheck(t *testing.T) {
-	v := New()
-	defer v.Shutdown()
+	v := setupNATSTest(t)
 
 	// Panic-check context has id=""
 	c := newContext("", "/", v)

pubsub.go

@@ -1,8 +1,9 @@
 package via
 
 // PubSub is an interface for publish/subscribe messaging backends.
-// By default, New() starts an embedded NATS server. Supply a custom
-// implementation via Config(Options{PubSub: yourBackend}) to override.
+// By default, Start() launches an embedded NATS server if no backend
+// has been configured. Supply a custom implementation via
+// Config(Options{PubSub: yourBackend}) to override.
 type PubSub interface {
 	Publish(subject string, data []byte) error
 	Subscribe(subject string, handler func(data []byte)) (Subscription, error)

pubsub_helpers_test.go

@@ -10,8 +10,7 @@ import (
 )
 
 func TestPublishSubscribe_RoundTrip(t *testing.T) {
-	v := New()
-	defer v.Shutdown()
+	v := setupNATSTest(t)
 
 	type event struct {
 		Name  string `json:"name"`
@@ -43,8 +42,7 @@ func TestPublishSubscribe_RoundTrip(t *testing.T) {
 }
 
 func TestSubscribe_SkipsBadJSON(t *testing.T) {
-	v := New()
-	defer v.Shutdown()
+	v := setupNATSTest(t)
 
 	type msg struct {
 		Text string `json:"text"`

via.go

@@ -139,6 +139,9 @@ func (v *V) Config(cfg Options) {
 		v.defaultNATS = nil
 		v.pubsub = cfg.PubSub
 	}
+	if cfg.ContextSuspendAfter != 0 {
+		v.cfg.ContextSuspendAfter = cfg.ContextSuspendAfter
+	}
 	if cfg.ContextTTL != 0 {
 		v.cfg.ContextTTL = cfg.ContextTTL
 	}
@@ -292,9 +295,16 @@ func (v *V) startReaper() {
 		return
 	}
 	if ttl == 0 {
-		ttl = 30 * time.Second
+		ttl = time.Hour
 	}
-	interval := ttl / 3
+	suspendAfter := v.cfg.ContextSuspendAfter
+	if suspendAfter == 0 {
+		suspendAfter = 15 * time.Minute
+	}
+	if suspendAfter > ttl {
+		suspendAfter = ttl
+	}
+	interval := suspendAfter / 3
 	if interval < 5*time.Second {
 		interval = 5 * time.Second
 	}
@@ -307,35 +317,42 @@ func (v *V) startReaper() {
 			case <-v.reaperStop:
 				return
 			case <-ticker.C:
-				v.reapOrphanedContexts(ttl)
+				v.reapOrphanedContexts(suspendAfter, ttl)
 			}
 		}
 	}()
 }
 
-func (v *V) reapOrphanedContexts(ttl time.Duration) {
+func (v *V) reapOrphanedContexts(suspendAfter, ttl time.Duration) {
 	now := time.Now()
 	v.contextRegistryMutex.RLock()
-	var orphans []*Context
+	var toSuspend, toReap []*Context
 	for _, c := range v.contextRegistry {
 		if c.sseConnected.Load() {
 			continue
 		}
-		if dc := c.sseDisconnectedAt.Load(); dc != nil {
-			// SSE was connected then dropped — reap if gone too long
-			if now.Sub(*dc) > ttl {
-				orphans = append(orphans, c)
+		// Use the most recent liveness signal
+		lastAlive := c.createdAt
+		if dc := c.sseDisconnectedAt.Load(); dc != nil && dc.After(lastAlive) {
+			lastAlive = *dc
 		}
-		} else {
-			// SSE never connected — reap based on creation time
-			if now.Sub(c.createdAt) > ttl {
-				orphans = append(orphans, c)
+		if seen := c.lastSeenAt.Load(); seen != nil && seen.After(lastAlive) {
+			lastAlive = *seen
 		}
+		silentFor := now.Sub(lastAlive)
+		if silentFor > ttl {
+			toReap = append(toReap, c)
+		} else if silentFor > suspendAfter && !c.suspended.Load() {
+			toSuspend = append(toSuspend, c)
 		}
 	}
 	v.contextRegistryMutex.RUnlock()
 
-	for _, c := range orphans {
+	for _, c := range toSuspend {
+		v.logInfo(c, "suspending context (no SSE connection after %s)", suspendAfter)
+		c.suspend()
+	}
+	for _, c := range toReap {
 		v.logInfo(c, "reaping orphaned context (no SSE connection after %s)", ttl)
 		v.cleanupCtx(c)
 	}
@@ -344,6 +361,16 @@ func (v *V) reapOrphanedContexts(ttl time.Duration) {
 // Start starts the Via HTTP server and blocks until a SIGINT or SIGTERM
 // signal is received, then performs a graceful shutdown.
 func (v *V) Start() {
+	if v.pubsub == nil {
+		dn, err := getSharedNATS()
+		if err != nil {
+			v.logWarn(nil, "embedded NATS unavailable: %v", err)
+		} else {
+			v.defaultNATS = dn
+			v.pubsub = &natsRef{dn: dn}
+		}
+	}
+
 	handler := http.Handler(v.mux)
 	if v.sessionManager != nil {
 		handler = v.sessionManager.LoadAndSave(v.mux)
@@ -625,10 +652,14 @@ func New() *V {
 		}
 		c, err := v.getCtx(cID)
 		if err != nil {
-			v.logErr(nil, "sse stream failed to start: %v", err)
+			v.logInfo(nil, "context expired, reloading client: %s", cID)
+			sse := datastar.NewSSE(w, r)
+			sse.ExecuteScript("window.location.reload()")
 			return
 		}
 		c.reqCtx = r.Context()
+		now := time.Now()
+		c.lastSeenAt.Store(&now)
 
 		sse := datastar.NewSSE(w, r, datastar.WithCompression(datastar.WithBrotli(datastar.WithBrotliLevel(5))))
 
@@ -650,19 +681,34 @@ func New() *V {
 		c.sseDisconnectedAt.Store(nil)
 		v.logDebug(c, "SSE connection established")
 
+		if c.suspended.Load() {
+			c.navMu.Lock()
+			c.suspended.Store(false)
+			if initFn := v.pageRegistry[c.route]; initFn != nil {
+				v.logInfo(c, "resuming suspended context")
+				initFn(c)
+			}
+			c.navMu.Unlock()
+		}
+
 		go c.Sync()
 
+		keepalive := time.NewTicker(30 * time.Second)
+		defer keepalive.Stop()
+
 		for {
 			select {
 			case <-sse.Context().Done():
 				v.logDebug(c, "SSE connection ended")
 				c.sseConnected.Store(false)
-				now := time.Now()
-				c.sseDisconnectedAt.Store(&now)
+				dcNow := time.Now()
+				c.sseDisconnectedAt.Store(&dcNow)
 				return
 			case <-c.ctxDisposedChan:
 				v.logDebug(c, "context disposed, closing SSE")
 				return
+			case <-keepalive.C:
+				sse.PatchSignals([]byte("{}"))
 			case patch := <-c.patchChan:
 				switch patch.typ {
 				case patchTypeElements:
@@ -807,14 +853,6 @@ func New() *V {
 		v.cleanupCtx(c)
 	})
 
-	dn, err := getSharedNATS()
-	if err != nil {
-		v.logWarn(nil, "embedded NATS unavailable: %v", err)
-	} else {
-		v.defaultNATS = dn
-		v.pubsub = &natsRef{dn: dn}
-	}
-
 	return v
 }
 

via_test.go

@@ -127,7 +127,7 @@ func TestAction(t *testing.T) {
 	v.mux.ServeHTTP(w, req)
 	body := w.Body.String()
 	assert.Contains(t, body, "data-on:click")
-	assert.Contains(t, body, "data-on:change__debounce.200ms")
+	assert.Contains(t, body, "data-on:change")
 	assert.Contains(t, body, "data-on:keydown")
 	assert.Contains(t, body, "/_action/")
 }
@@ -281,6 +281,112 @@ func TestOnKeyDownMap(t *testing.T) {
 	})
 }
 
+func TestFormatDuration(t *testing.T) {
+	tests := []struct {
+		d    time.Duration
+		want string
+	}{
+		{200 * time.Millisecond, "200ms"},
+		{1 * time.Second, "1000ms"},
+		{50 * time.Millisecond, "50ms"},
+	}
+	for _, tt := range tests {
+		assert.Equal(t, tt.want, formatDuration(tt.d))
+	}
+}
+
+func TestBuildAttrKey(t *testing.T) {
+	tests := []struct {
+		name  string
+		event string
+		opts  triggerOpts
+		want  string
+	}{
+		{"bare event", "click", triggerOpts{}, "on:click"},
+		{"debounce only", "change", triggerOpts{debounce: 200 * time.Millisecond}, "on:change__debounce.200ms"},
+		{"throttle only", "scroll", triggerOpts{throttle: 100 * time.Millisecond}, "on:scroll__throttle.100ms"},
+		{"window only", "keydown", triggerOpts{window: true}, "on:keydown__window"},
+		{"debounce + window", "input", triggerOpts{debounce: 300 * time.Millisecond, window: true}, "on:input__debounce.300ms__window"},
+		{"throttle + window", "scroll", triggerOpts{throttle: 500 * time.Millisecond, window: true}, "on:scroll__throttle.500ms__window"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, buildAttrKey(tt.event, &tt.opts))
+		})
+	}
+}
+
+func TestWithDebounce(t *testing.T) {
+	var trigger *actionTrigger
+	v := New()
+	v.Page("/", func(c *Context) {
+		trigger = c.Action(func() {})
+		c.View(func() h.H {
+			return h.Button(trigger.OnClick(WithDebounce(300 * time.Millisecond)))
+		})
+	})
+
+	req := httptest.NewRequest("GET", "/", nil)
+	w := httptest.NewRecorder()
+	v.mux.ServeHTTP(w, req)
+	body := w.Body.String()
+	assert.Contains(t, body, "data-on:click__debounce.300ms")
+	assert.Contains(t, body, "/_action/"+trigger.id)
+}
+
+func TestWithThrottle(t *testing.T) {
+	var trigger *actionTrigger
+	v := New()
+	v.Page("/", func(c *Context) {
+		trigger = c.Action(func() {})
+		c.View(func() h.H {
+			return h.Div(trigger.OnScroll(WithThrottle(100 * time.Millisecond)))
+		})
+	})
+
+	req := httptest.NewRequest("GET", "/", nil)
+	w := httptest.NewRecorder()
+	v.mux.ServeHTTP(w, req)
+	body := w.Body.String()
+	assert.Contains(t, body, "data-on:scroll__throttle.100ms")
+	assert.Contains(t, body, "/_action/"+trigger.id)
+}
+
+func TestWithDebounceOnChange(t *testing.T) {
+	var trigger *actionTrigger
+	v := New()
+	v.Page("/", func(c *Context) {
+		trigger = c.Action(func() {})
+		c.View(func() h.H {
+			return h.Input(trigger.OnChange(WithDebounce(200 * time.Millisecond)))
+		})
+	})
+
+	req := httptest.NewRequest("GET", "/", nil)
+	w := httptest.NewRecorder()
+	v.mux.ServeHTTP(w, req)
+	body := w.Body.String()
+	assert.Contains(t, body, "data-on:change__debounce.200ms")
+	assert.Contains(t, body, "/_action/"+trigger.id)
+}
+
+func TestDebounceWithWindow(t *testing.T) {
+	var trigger *actionTrigger
+	v := New()
+	v.Page("/", func(c *Context) {
+		trigger = c.Action(func() {})
+		c.View(func() h.H {
+			return h.Div(trigger.OnKeyDown("Enter", WithDebounce(150*time.Millisecond), WithWindow()))
+		})
+	})
+
+	req := httptest.NewRequest("GET", "/", nil)
+	w := httptest.NewRecorder()
+	v.mux.ServeHTTP(w, req)
+	body := w.Body.String()
+	assert.Contains(t, body, "data-on:keydown__debounce.150ms__window")
+}
+
 func TestConfig(t *testing.T) {
 	v := New()
 	v.Config(Options{DocumentTitle: "Test"})
@@ -303,12 +409,66 @@ func TestReaperCleansOrphanedContexts(t *testing.T) {
 	_, err := v.getCtx("orphan-1")
 	assert.NoError(t, err)
 
-	v.reapOrphanedContexts(10 * time.Second)
+	v.reapOrphanedContexts(5*time.Second, 10*time.Second)
 
 	_, err = v.getCtx("orphan-1")
 	assert.Error(t, err, "orphaned context should have been reaped")
 }
 
+func TestReaperSuspendsContext(t *testing.T) {
+	v := New()
+	c := newContext("suspend-1", "/", v)
+	c.createdAt = time.Now().Add(-30 * time.Minute)
+	dc := time.Now().Add(-20 * time.Minute)
+	c.sseDisconnectedAt.Store(&dc)
+	v.registerCtx(c)
+
+	v.reapOrphanedContexts(15*time.Minute, time.Hour)
+
+	got, err := v.getCtx("suspend-1")
+	assert.NoError(t, err, "suspended context should still be in registry")
+	assert.True(t, got.suspended.Load(), "context should be marked suspended")
+}
+
+func TestReaperReapsAfterTTL(t *testing.T) {
+	v := New()
+	c := newContext("reap-1", "/", v)
+	c.createdAt = time.Now().Add(-3 * time.Hour)
+	dc := time.Now().Add(-2 * time.Hour)
+	c.sseDisconnectedAt.Store(&dc)
+	c.suspended.Store(true)
+	v.registerCtx(c)
+
+	v.reapOrphanedContexts(15*time.Minute, time.Hour)
+
+	_, err := v.getCtx("reap-1")
+	assert.Error(t, err, "context past TTL should have been reaped")
+}
+
+func TestReaperIgnoresAlreadySuspended(t *testing.T) {
+	v := New()
+	c := newContext("already-sus-1", "/", v)
+	c.createdAt = time.Now().Add(-30 * time.Minute)
+	dc := time.Now().Add(-20 * time.Minute)
+	c.sseDisconnectedAt.Store(&dc)
+	c.suspended.Store(true)
+	// give it a fresh pageStopChan so we can verify it's not re-closed
+	c.pageStopChan = make(chan struct{})
+	v.registerCtx(c)
+
+	v.reapOrphanedContexts(15*time.Minute, time.Hour)
+
+	got, err := v.getCtx("already-sus-1")
+	assert.NoError(t, err, "already-suspended context within TTL should survive")
+	assert.True(t, got.suspended.Load())
+	// pageStopChan should still be open (not re-suspended)
+	select {
+	case <-got.pageStopChan:
+		t.Fatal("pageStopChan was closed — context was re-suspended")
+	default:
+	}
+}
+
 func TestReaperIgnoresConnectedContexts(t *testing.T) {
 	v := New()
 	c := newContext("connected-1", "/", v)
@@ -316,7 +476,7 @@ func TestReaperIgnoresConnectedContexts(t *testing.T) {
 	c.sseConnected.Store(true)
 	v.registerCtx(c)
 
-	v.reapOrphanedContexts(10 * time.Second)
+	v.reapOrphanedContexts(5*time.Second, 10*time.Second)
 
 	_, err := v.getCtx("connected-1")
 	assert.NoError(t, err, "connected context should survive reaping")
@@ -343,6 +503,74 @@ func TestCleanupCtxIdempotent(t *testing.T) {
 	assert.Error(t, err, "context should be removed after cleanup")
 }
 
+func TestReaperRespectsLastSeenAt(t *testing.T) {
+	v := New()
+	c := newContext("seen-1", "/", v)
+	c.createdAt = time.Now().Add(-30 * time.Minute)
+	// Disconnected 20 min ago, but client retried (lastSeenAt) 2 min ago
+	dc := time.Now().Add(-20 * time.Minute)
+	c.sseDisconnectedAt.Store(&dc)
+	seen := time.Now().Add(-2 * time.Minute)
+	c.lastSeenAt.Store(&seen)
+	v.registerCtx(c)
+
+	v.reapOrphanedContexts(15*time.Minute, time.Hour)
+
+	_, err := v.getCtx("seen-1")
+	assert.NoError(t, err, "context with recent lastSeenAt should survive suspend threshold")
+	assert.False(t, c.suspended.Load(), "context should not be suspended")
+}
+
+func TestReaperFallsBackWithoutLastSeenAt(t *testing.T) {
+	v := New()
+	c := newContext("noseen-1", "/", v)
+	c.createdAt = time.Now().Add(-30 * time.Minute)
+	dc := time.Now().Add(-20 * time.Minute)
+	c.sseDisconnectedAt.Store(&dc)
+	// no lastSeenAt set — should fall back to sseDisconnectedAt
+	v.registerCtx(c)
+
+	v.reapOrphanedContexts(15*time.Minute, time.Hour)
+
+	got, err := v.getCtx("noseen-1")
+	assert.NoError(t, err, "context should still be in registry (suspended, not reaped)")
+	assert.True(t, got.suspended.Load(), "context should be suspended using sseDisconnectedAt fallback")
+}
+
+func TestReaperReapsWithStaleLastSeenAt(t *testing.T) {
+	v := New()
+	c := newContext("stale-seen-1", "/", v)
+	c.createdAt = time.Now().Add(-3 * time.Hour)
+	dc := time.Now().Add(-2 * time.Hour)
+	c.sseDisconnectedAt.Store(&dc)
+	// lastSeenAt is also old — beyond TTL
+	seen := time.Now().Add(-90 * time.Minute)
+	c.lastSeenAt.Store(&seen)
+	c.suspended.Store(true)
+	v.registerCtx(c)
+
+	v.reapOrphanedContexts(15*time.Minute, time.Hour)
+
+	_, err := v.getCtx("stale-seen-1")
+	assert.Error(t, err, "context with stale lastSeenAt beyond TTL should be reaped")
+}
+
+func TestLastSeenAtUpdatedOnSSEConnect(t *testing.T) {
+	v := New()
+	c := newContext("seen-sse-1", "/", v)
+	v.registerCtx(c)
+
+	assert.Nil(t, c.lastSeenAt.Load(), "lastSeenAt should be nil before SSE connect")
+
+	// Simulate what the SSE handler does after getCtx
+	now := time.Now()
+	c.lastSeenAt.Store(&now)
+
+	got := c.lastSeenAt.Load()
+	assert.NotNil(t, got, "lastSeenAt should be set after SSE connect")
+	assert.WithinDuration(t, now, *got, time.Second)
+}
+
 func TestDevModeRemovePersistedFix(t *testing.T) {
 	v := New()
 	v.cfg.DevMode = true