Request ID Middleware

Request ID Middleware generates a unique ID for each request, which you can use in your handlers.

Import

import { Hono } from 'hono'
import { requestId } from 'hono/request-id'

Usage

You can access the Request ID through the requestId variable in the handlers and middleware to which the Request ID Middleware is applied.

const app = new Hono()

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

app.get('/', (c) => {
  return c.text(`Your request id is ${c.get('requestId')}`)
})

If you want to explicitly specify the type, import RequestIdVariables and pass it in the generics of new Hono().

import type { RequestIdVariables } from 'hono/request-id'

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

Set Request ID

You set a custom request ID in the header (default: X-Request-Id), the middleware will use that value instead of generating a new one:

const app = new Hono()

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

app.get('/', (c) => {
  return c.text(`${c.get('requestId')}`)
})

const res = await app.request('/', {
  headers: {
    'X-Request-Id': 'your-custom-id',
  },
})
console.log(await res.text()) // your-custom-id

If you want to disable this feature, set headerName option to an empty string.

Options

optional limitLength: number

The maximum length of the request ID. The default is 255.

optional headerName: string

The header name used for the request ID. The default is X-Request-Id.

optional generator: (c: Context) => string

The request ID generation function. By default, it uses crypto.randomUUID().