Modifying Request Headers in Middleware

Add Header Example

Below is the code from middleware.ts [blocked] showing how to add/update/delete headers in a middleware (available since Next.js v13.0.0):

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import { NextResponse } from 'next/server'
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import type { NextRequest } from 'next/server'
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export default function middleware(request: NextRequest) {
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  // Clone the request headers
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  // You can modify them with headers API: https://developer.mozilla.org/en-US/docs/Web/API/Headers
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  const requestHeaders = new Headers(request.headers)
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  // Add new request headers
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  requestHeaders.set('x-hello-from-middleware1', 'hello')
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  requestHeaders.set('x-hello-from-middleware2', 'world!')
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  // Update an existing request header
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  requestHeaders.set('user-agent', 'New User Agent overriden by middleware!')
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  // Delete an existing request header
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  requestHeaders.delete('x-from-client')
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  // You can also set request headers in NextResponse.rewrite
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  return NextResponse.next({
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    request: {
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      // New request headers
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      headers: requestHeaders,
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    },
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  })
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}

Demo

https://edge-middleware-modify-request-header.vercel.app

How to Use

You can choose from one of the following two methods to use this repository:

One-Click Deploy

Deploy the example using Vercel:

Clone and Deploy

Execute create-next-app with pnpm to bootstrap the example:

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pnpm create next-app --example https://github.com/vercel/examples/tree/main/edge-middleware/modify-request-header modify-request-header

Next, run Next.js in development mode:

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pnpm dev

Deploy it to the cloud with Vercel (Documentation).