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// http header · cors header

Access-Control-Max-Age

How long a preflight result can be cached

What the Access-Control-Max-Age header does

Access-Control-Max-Age says how long (in seconds) the browser may cache a CORS preflight result, so repeated cross-origin requests don't each trigger an extra OPTIONS round trip.

Example

Access-Control-Max-Age: 600

Where it's used

Access-Control-Max-Age is a cors header. CORS headers govern cross-origin requests — which other origins may read a response.

Other cors headers

Access-Control-Allow-Origin Access-Control-Allow-Methods Access-Control-Allow-Headers Access-Control-Allow-Credentials Access-Control-Max-Age
TOOL

HTTP Headers Parser

Turn a block of raw headers into readable JSON.

REFERENCE

All HTTP Headers

Common request, response, caching, CORS, and security headers.

GUIDE

How to Read and Parse HTTP Headers

The anatomy of headers and how to work with them.