Request & response reference

HTTP Header Cheatsheet

Search common HTTP request and response headers and see a plain-English explanation of each — instantly, right in your browser.

How it works

1

Search or filter

Type a header name or a keyword, or filter by request, response or both.

2

Read the explanation

Each header gets a short, plain-English description of what it does.

3

Reference while you build

Keep it open in a tab while debugging APIs or writing server code.

FAQ

What is the difference between a request and response header?

Request headers are sent by the client to describe the request, such as Accept or Authorization. Response headers are sent back by the server, such as Content-Type or Set-Cookie. Some headers, like Cache-Control, can appear in both.

Is this list of headers complete?

It covers the HTTP headers developers encounter most often when building and debugging web APIs. Highly specialized or draft headers are not included.

Can I search by what a header does?

Yes. The search box matches both header names and their descriptions, so searching "cors" or "caching" surfaces relevant headers.

Try other tools

MIMEMIME Type LookupSearch extensions and MIME types. HTTPHTTP Status LookupExplain response codes. curlcURL Command BuilderBuild a curl command visually.