Via

Real-time engine for building reactive web applications in pure Go.

Why Via?

The web became tangled in layers of JavaScript, build chains, and frameworks stacked on frameworks. Via takes a different path.

Philosophy

• No templates. No JavaScript. No transpilation. No hydration.
• Views are pure Go functions. HTML is composed with a type-safe DSL.
• A single SSE stream carries all reactivity — no WebSocket juggling, no polling.

Batteries included

• Automatic CSRF protection on every action call
• Token-bucket rate limiting (global defaults + per-action overrides)
• Cookie-based sessions backed by SQLite
• Pub/sub messaging with an embedded NATS backend
• Structured logging via zerolog
• Graceful shutdown with context draining
• Brotli compression out of the box

Example

package main

import (
	"github.com/ryanhamamura/via"
	"github.com/ryanhamamura/via/h"
)

type Counter struct{ Count int }

func main() {
	v := via.New()

	v.Page("/", func(c *via.Context) {
		data := Counter{Count: 0}
		step := c.Signal(1)

		increment := c.Action(func() {
			data.Count += step.Int()
			c.Sync()
		})

		c.View(func() h.H {
			return h.Div(
				h.P(h.Textf("Count: %d", data.Count)),
				h.Label(
					h.Text("Update Step: "),
					h.Input(h.Type("number"), step.Bind()),
				),
				h.Button(h.Text("Increment"), increment.OnClick()),
			)
		})
	})

	v.Start()
}

What's built in

• Reactive views + signals — bind state to the DOM; changes push over SSE automatically
• Components — self-contained subcontexts with their own data, actions, and signals
• Sessions — cookie-based, backed by SQLite via scs
• Pub/sub — embedded NATS server with JetStream; generic Publish[T] / Subscribe[T] helpers
• CSRF protection — automatic token generation and validation on every action
• Rate limiting — token-bucket algorithm, configurable globally and per-action
• Event handling — OnClick, OnChange, OnSubmit, OnInput, OnFocus, OnBlur, OnMouseEnter, OnMouseLeave, OnScroll, OnDblClick, OnKeyDown, and OnKeyDownMap for multi-key bindings
• Timed routines — OnInterval auto-starts a ticker goroutine, returns a stop function, tied to context lifecycle
• Redirects — Redirect, ReplaceURL, and format-string variants
• Plugin system — func(v *V) hooks for integrating CSS/JS libraries
• Structured logging — zerolog with configurable levels; console output in dev, JSON in production
• Graceful shutdown — listens for SIGINT/SIGTERM, drains contexts, closes pub/sub
• Context lifecycle — background reaper cleans up disconnected contexts; configurable TTL
• HTML DSL — the h package provides type-safe Go-native HTML composition

Examples

The internal/examples/ directory contains 14 runnable examples:

chatroom · counter · countercomp · greeter · keyboard · livereload · nats-chatroom · pathparams · picocss · plugins · pubsub-crud · realtimechart · session · shakespeare

Experimental

Via is maturing — sessions, CSRF, rate limiting, pub/sub, and graceful shutdown are in place — but the API is still evolving. Expect breaking changes before v1.

Contributing

• Via is intentionally minimal and opinionated — and so is contributing.
• Fork, branch, build, tinker, submit a pull request.
• Keep every line purposeful.
• Share feedback: open an issue or start a discussion.

Credits

Via builds upon the work of these projects:

• Datastar — the hypermedia framework powering browser reactivity through signals and real-time HTML patches over SSE.
• Gomponents — Go-native HTML composition that powers the via/h package.