http header
Access-Control-Request-Headers header
The HTTP Access-Control-Request-Headers request header is used by browsers when issuing a preflight request to let the server know which HTTP headers the client might send when the actual request is made (such as with fetch() or setRequestHeader()). The complementary server-side header of Access-Control-Allow-Headers will answer this browser-side header.
| Header type | [Request header](https://developer.mozilla.org/en-US/docs/Glossary/Request%20header) |
|---|---|
| [Forbidden request header](https://developer.mozilla.org/en-US/docs/Glossary/Forbidden%20request%20header) | Yes |
Syntax
Access-Control-Request-Headers: <header-name>,<header-name>,…
Directives
<header-name>- : A sorted list of unique, comma-separated, lowercase HTTP headers that are included in the request.
Examples
Access-Control-Request-Headers: content-type,x-pingother
Specifications
SpecificationsStandards references are available on the canonical MDN page.
Browser compatibility
Browser compatibilityCompatibility data is available on the canonical MDN page.