| Header | Type | Description | Example |
|---|
HTTP headers are key-value pairs sent alongside every request and response to carry metadata such as content type, caching rules, authentication credentials, cookies and cross-origin permissions. Request headers are set by the client (browser or API caller); response headers are set by the server; some headers are general and may appear in either direction. This page lists 50+ of the headers you meet most often, with their direction, a plain-language description and a realistic example value.
Type in the search box to filter by header name (like Content-Type), direction (Request/Response) or any word in the description. This is handy when debugging CORS, caching, authentication or content negotiation. Everything runs locally in your browser.