Built-in Middleware

Middleware lets you add behavior around routes. Hono includes middleware for common web application needs.

Logging and security

Start with middleware that applies broadly.

import { logger } from 'hono/logger'
import { secureHeaders } from 'hono/secure-headers'

app.use(logger())
app.use(secureHeaders())

logger() helps during development and operations. secureHeaders() adds common security headers to responses.

CORS

Use CORS when browsers need to call your API from another origin.

import { cors } from 'hono/cors'

app.use(
  '/api/*',
  cors({
    origin: 'https://example.com',
  })
)

Keep CORS scoped to the routes that need browser access from another site.

Cache helpers

ETag and cache middleware can reduce repeated work.

import { etag } from 'hono/etag'

app.use(etag())

For a mostly static book like this one, caching middleware can be useful around rendered pages and chapter responses.

Basic Auth

Basic Auth is useful for small private areas or previews.

import { basicAuth } from 'hono/basic-auth'

app.use(
  '/admin/*',
  basicAuth({
    username: 'admin',
    password: 'secret',
  })
)

Middleware order matters. Register broad middleware first, then add route-specific middleware closer to the routes that need it.