# httprouter — Lightweight High-Performance HTTP Router for Go

> httprouter is a high-performance HTTP request router for Go that uses a radix tree for efficient path matching with zero garbage collection overhead.

## Install

Save in your project root:

# httprouter — Lightweight High-Performance HTTP Router for Go

## Quick Use
```bash
go get github.com/julienschmidt/httprouter
```

```go
package main

import (
    "fmt"
    "net/http"
    "github.com/julienschmidt/httprouter"
)

func main() {
    router := httprouter.New()
    router.GET("/hello/:name", func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
        fmt.Fprintf(w, "Hello, %s!", ps.ByName("name"))
    })
    http.ListenAndServe(":8080", router)
}
```

## Introduction
httprouter is a minimal Go HTTP router focused purely on speed and correctness. It uses a compressed radix tree (trie) for route matching, which means lookups are independent of the number of registered routes. The library is a popular foundation for higher-level frameworks like Gin.

## What httprouter Does
- Matches HTTP routes using a compressed radix tree with zero allocations on the hot path
- Supports named parameters (`:name`) and catch-all parameters (`*filepath`)
- Implements the standard http.Handler interface for net/http compatibility
- Detects conflicting routes at registration time to prevent ambiguity
- Provides automatic OPTIONS and 405 Method Not Allowed responses

## Architecture Overview
The router stores each HTTP method's routes in a separate radix tree. When a request arrives, it walks the tree character-by-character, resolving named and wildcard segments along the way. Because the tree is compressed, common prefixes share a single node, keeping memory usage low. Parameters are extracted into a slice that is stack-allocated in most cases, avoiding heap allocation entirely.

## Self-Hosting & Configuration
- Install with `go get github.com/julienschmidt/httprouter` (Go 1.18+)
- Register routes with `router.GET`, `router.POST`, etc. for each HTTP method
- Set `router.NotFound` to a custom handler for 404 responses
- Set `router.PanicHandler` to recover from panics inside handlers gracefully
- Enable trailing-slash redirects with `router.RedirectTrailingSlash = true`

## Key Features
- Only router in Go with truly zero heap allocation per request
- Named and catch-all path parameters with no regex overhead
- Conflict detection at startup prevents silent route shadowing
- Fully compatible with net/http middleware via http.Handler
- Battle-tested as the routing engine inside the Gin framework

## Comparison with Similar Tools
- **Gorilla Mux** — regex-based matching, more flexible but slower lookup
- **Chi** — radix tree like httprouter, but adds middleware chaining and context support
- **Gin** — full framework built on httprouter with middleware, logging, and JSON helpers
- **net/http DefaultServeMux** — simple prefix matching, no parameters or method routing

## FAQ
**Q: Why choose httprouter over Gin?**
A: httprouter is just a router. If you want only routing without framework overhead, it is the lighter choice. Gin adds middleware, binding, and rendering on top.

**Q: Does httprouter support middleware?**
A: Not directly. You can wrap handlers manually or use a library like Alice to chain http.Handler middleware.

**Q: Can httprouter handle regex routes?**
A: No. It supports named parameters and catch-alls only. For regex-based routing, consider Gorilla Mux.

**Q: Is httprouter still maintained?**
A: Yes. Development is stable with occasional updates, and its API is considered complete.

## Sources
- https://github.com/julienschmidt/httprouter
- https://pkg.go.dev/github.com/julienschmidt/httprouter

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Author: AI Open Source