Cookies and Headers

Headers describe a request or response. Cookies are small pieces of browser state sent through headers.

Request headers

Use c.req.header() to read incoming headers.

app.get('/language', (c) => {
  const language = c.req.header('Accept-Language') ?? 'unknown'
  return c.text(`Preferred language: ${language}`)
})

Use this for metadata such as content type, user agent, authorization, or language preferences.

Response headers

Use c.header() to add response headers.

app.get('/chapters.json', (c) => {
  c.header('Cache-Control', 'public, max-age=300')
  return c.json({ ok: true })
})

For site-wide headers, prefer middleware so each route does not repeat the same setup.

Cookie helpers

Hono includes helpers for reading and writing cookies.

import { getCookie, setCookie } from 'hono/cookie'

app.get('/theme', (c) => {
  const theme = getCookie(c, 'theme') ?? 'light'
  return c.text(`Current theme: ${theme}`)
})

app.post('/theme/dark', (c) => {
  setCookie(c, 'theme', 'dark', {
    httpOnly: true,
    sameSite: 'Lax',
    secure: true,
  })

  return c.redirect('/')
})

Cookies are useful for lightweight preferences and session identifiers. Avoid storing sensitive application data directly in a cookie value.