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Alter headers

Change the headers sent in a request or returned in a response.

addEventListener('fetch', event => {
event.respondWith(handleRequest(event.request))
})
async function handleRequest(request) {
const response = await fetch(request)
// Clone the response so that it's no longer immutable
const newResponse = new Response(response.body, response)
// Add a custom header with a value
newResponse.headers.append("x-workers-hello", "Hello from Cloudflare Workers")
// Delete headers
newResponse.headers.delete("x-header-to-delete")
newResponse.headers.delete("x-header2-to-delete")
// Adjust the value for an existing header
newResponse.headers.set("x-header-to-change", "NewValue")
return newResponse
}

You can also use the custom-headers-example template to deploy this code to your custom domain.