The Pragma HTTP/1.0 general header is an implementation-specific header that may have various effects along the request-response chain. It is used for backwards compatibility with HTTP/1.0 caches where the Cache-Control HTTP/1.1 header is not yet present.
Note: Pragma is not specified for HTTP responses and is therefore not a reliable replacement for the general HTTP/1.1 Cache-Control header, although it does behave the same as Cache-Control: no-cache, if the Cache-Control header field is omitted in a request. Use Pragma only for backwards compatibility with HTTP/1.0 clients.
| Header type | General header, but response behavior is not specified and thus implementation-specific. |
|---|---|
| Forbidden header name | no |
| CORS-safelisted response-header | yes |
Pragma: no-cache
Same as Cache-Control: no-cache. Forces caches to submit the request to the origin server for validation before releasing a cached copy.
Pragma: no-cache
| Specification | Title |
|---|---|
| RFC 7234, section 5.4: Pragma | Hypertext Transfer Protocol (HTTP/1.1): Caching |
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | Servo |
|---|---|---|---|---|---|---|---|
| Pragma | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
| Feature | Android | Chrome for Android | Edge Mobile | Firefox for Android | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|---|
| Pragma | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
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https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Pragma