hono-routing

Hono Routing & Middleware

Status: Production Ready ✅ Last Updated: 2025-10-22 Dependencies: None (framework-agnostic) Latest Versions: hono@4.10.2, zod@4.1.12, valibot@1.1.0, @hono/zod-validator@0.7.4, @hono/valibot-validator@0.5.3

Quick Start (15 Minutes)

1. Install Hono

npm install hono@4.10.2

Why Hono:

• Fast: Built on Web Standards, runs on any JavaScript runtime
• Lightweight: ~10KB, no dependencies
• Type-safe: Full TypeScript support with type inference
• Flexible: Works on Cloudflare Workers, Deno, Bun, Node.js, Vercel

2. Create Basic App

import { Hono } from 'hono'

const app = new Hono()

app.get('/', (c) => {
  return c.json({ message: 'Hello Hono!' })
})

export default app

CRITICAL:

• Use c.json(), c.text(), c.html() for responses
• Return the response (don't use res.send() like Express)
• Export app for runtime (Cloudflare Workers, Deno, Bun, Node.js)

3. Add Request Validation

npm install zod@4.1.12 @hono/zod-validator@0.7.4

import { zValidator } from '@hono/zod-validator'
import { z } from 'zod'

const schema = z.object({
  name: z.string(),
  age: z.number(),
})

app.post('/user', zValidator('json', schema), (c) => {
  const data = c.req.valid('json')
  return c.json({ success: true, data })
})

Why Validation:

• Type-safe request data
• Automatic error responses
• Runtime validation, not just TypeScript

The 6-Part Hono Mastery Guide

Part 1: Routing Patterns

Basic Routes

import { Hono } from 'hono'

const app = new Hono()

// GET request
app.get('/posts', (c) => c.json({ posts: [] }))

// POST request
app.post('/posts', (c) => c.json({ created: true }))

// PUT request
app.put('/posts/:id', (c) => c.json({ updated: true }))

// DELETE request
app.delete('/posts/:id', (c) => c.json({ deleted: true }))

// Multiple methods
app.on(['GET', 'POST'], '/multi', (c) => c.text('GET or POST'))

// All methods
app.all('/catch-all', (c) => c.text('Any method'))

Key Points:

• Always return a Response (c.json, c.text, c.html, etc.)
• Routes are matched in order (first match wins)
• Use specific routes before wildcard routes

Route Parameters

// Single parameter
app.get('/users/:id', (c) => {
  const id = c.req.param('id')
  return c.json({ userId: id })
})

// Multiple parameters
app.get('/posts/:postId/comments/:commentId', (c) => {
  const { postId, commentId } = c.req.param()
  return c.json({ postId, commentId })
})

// Optional parameters (using wildcards)
app.get('/files/*', (c) => {
  const path = c.req.param('*')
  return c.json({ filePath: path })
})

CRITICAL:

• c.req.param('name') returns single parameter
• c.req.param() returns all parameters as object
• Parameters are always strings (cast to number if needed)

Query Parameters

app.get('/search', (c) => {
  // Single query param
  const q = c.req.query('q')

  // Multiple query params
  const { page, limit } = c.req.query()

  // Query param array (e.g., ?tag=js&tag=ts)
  const tags = c.req.queries('tag')

  return c.json({ q, page, limit, tags })
})

Best Practice:

• Use validation for query params (see Part 4)
• Provide defaults for optional params
• Parse numbers/booleans from query strings

Wildcard Routes

// Match any path after /api/
app.get('/api/*', (c) => {
  const path = c.req.param('*')
  return c.json({ catchAll: path })
})

// Named wildcard
app.get('/files/:filepath{.+}', (c) => {
  const filepath = c.req.param('filepath')
  return c.json({ file: filepath })
})

Route Grouping (Sub-apps)

// Create sub-app
const api = new Hono()

api.get('/users', (c) => c.json({ users: [] }))
api.get('/posts', (c) => c.json({ posts: [] }))

// Mount sub-app
const app = new Hono()
app.route('/api', api)

// Result: /api/users, /api/posts

Why Group Routes:

• Organize large applications
• Share middleware for specific routes
• Better code structure and maintainability

Part 2: Middleware Composition

Middleware Flow

import { Hono } from 'hono'

const app = new Hono()

// Global middleware (runs for all routes)
app.use('*', async (c, next) => {
  console.log(`[${c.req.method}] ${c.req.url}`)
  await next() // CRITICAL: Must call next()
  console.log('Response sent')
})

// Route-specific middleware
app.use('/admin/*', async (c, next) => {
  // Auth check
  const token = c.req.header('Authorization')
  if (!token) {
    return c.json({ error: 'Unauthorized' }, 401)
  }
  await next()
})

app.get('/admin/dashboard', (c) => {
  return c.json({ message: 'Admin Dashboard' })
})

CRITICAL:

• Always call await next() in middleware
• Middleware runs BEFORE the handler
• Return early to prevent handler execution
• Check c.error AFTER next() for error handling

Built-in Middleware

import { Hono } from 'hono'
import { logger } from 'hono/logger'
import { cors } from 'hono/cors'
import { prettyJSON } from 'hono/pretty-json'
import { compress } from 'hono/compress'
import { cache } from 'hono/cache'

const app = new Hono()

// Request logging
app.use('*', logger())

// CORS
app.use('/api/*', cors({
  origin: 'https://example.com',
  allowMethods: ['GET', 'POST', 'PUT', 'DELETE'],
  allowHeaders: ['Content-Type', 'Authorization'],
}))

// Pretty JSON (dev only)
app.use('*', prettyJSON())

// Compression (gzip/deflate)
app.use('*', compress())

// Cache responses
app.use(
  '/static/*',
  cache({
    cacheName: 'my-app',
    cacheControl: 'max-age=3600',
  })
)

Built-in Middleware Reference: See references/middleware-catalog.md

Middleware Chaining

// Multiple middleware in sequence
app.get(
  '/protected',
  authMiddleware,
  rateLimitMiddleware,
  (c) => {
    return c.json({ data: 'Protected data' })
  }
)

// Middleware factory pattern
const authMiddleware = async (c, next) => {
  const token = c.req.header('Authorization')
  if (!token) {
    throw new HTTPException(401, { message: 'Unauthorized' })
  }

  // Set user in context
  c.set('user', { id: 1, name: 'Alice' })

  await next()
}

const rateLimitMiddleware = async (c, next) => {
  // Rate limit logic
  await next()
}

Why Chain Middleware:

• Separation of concerns
• Reusable across routes
• Clear execution order

Custom Middleware

// Timing middleware
const timing = async (c, next) => {
  const start = Date.now()
  await next()
  const elapsed = Date.now() - start
  c.res.headers.set('X-Response-Time', `${elapsed}ms`)
}

// Request ID middleware
const requestId = async (c, next) => {
  const id = crypto.randomUUID()
  c.set('requestId', id)
  await next()
  c.res.headers.set('X-Request-ID', id)
}

// Error logging middleware
const errorLogger = async (c, next) => {
  await next()
  if (c.error) {
    console.error('Error:', c.error)
    // Send to error tracking service
  }
}

app.use('*', timing)
app.use('*', requestId)
app.use('*', errorLogger)

Best Practices:

• Keep middleware focused (single responsibility)
• Use c.set() to share data between middleware
• Check c.error AFTER next() for error handling
• Return early to short-circuit execution

Part 3: Type-Safe Context Extension

Using c.set() and c.get()

import { Hono } from 'hono'

type Bindings = {
  DATABASE_URL: string
}

type Variables = {
  user: {
    id: number
    name: string
  }
  requestId: string
}

const app = new Hono<{ Bindings: Bindings; Variables: Variables }>()

// Middleware sets variables
app.use('*', async (c, next) => {
  c.set('requestId', crypto.randomUUID())
  await next()
})

app.use('/api/*', async (c, next) => {
  c.set('user', { id: 1, name: 'Alice' })
  await next()
})

// Route accesses variables
app.get('/api/profile', (c) => {
  const user = c.get('user') // Type-safe!
  const requestId = c.ge