# HTTP header fields (IANA registry) | Field name | Status | Structured type | Defining RFC | References | Comments | | --- | --- | --- | ---: | --- | --- | | * | permanent | | 9110 | RFC 9110, Section 12.5.5 | (reserved) | | A-IM | permanent | | 3229 | RFC 3229 | | | ALPN | permanent | | 7639 | RFC 7639, Section 2 | | | AMP-Cache-Transform | provisional | | | | | | Accept | permanent | | 9110 | RFC 9110, Section 12.5.1 | | | Accept-Additions | permanent | | 2324 | RFC 2324 | | | Accept-CH | permanent | List | 8942 | RFC 8942, Section 3.1 | | | Accept-Charset | deprecated | | 9110 | RFC 9110, Section 12.5.2 | | | Accept-Datetime | permanent | | 7089 | RFC 7089 | | | Accept-Encoding | permanent | | 9110 | RFC 9110, Section 12.5.3 | | | Accept-Features | permanent | | 2295 | RFC 2295 | | | Accept-Language | permanent | | 9110 | RFC 9110, Section 12.5.4 | | | Accept-Patch | permanent | | 5789 | RFC 5789 | | | Accept-Post | permanent | | | | | | Accept-Query | permanent | List | 10008 | RFC 10008, Section 3 | | | Accept-Ranges | permanent | | 9110 | RFC 9110, Section 14.3 | | | Accept-Signature | permanent | | 9421 | RFC 9421, Section 5.1 | | | Access-Control | obsoleted | | | | | | Access-Control-Allow-Credentials | permanent | | | | | | Access-Control-Allow-Headers | permanent | | | | | | Access-Control-Allow-Methods | permanent | | | | | | Access-Control-Allow-Origin | permanent | | | | | | Access-Control-Expose-Headers | permanent | | | | | | Access-Control-Max-Age | permanent | | | | | | Access-Control-Request-Headers | permanent | | | | | | Access-Control-Request-Method | permanent | | | | | | Activate-Storage-Access | provisional | Item | | https://privacycg.github.io/storage-access-headers | | | Age | permanent | | 9111 | RFC 9111, Section 5.1 | | | Allow | permanent | | 9110 | RFC 9110, Section 10.2.1 | | | Alt-Svc | permanent | | 7838 | RFC 7838 | | | Alt-Used | permanent | | 7838 | RFC 7838 | | | Alternates | permanent | | 2295 | RFC 2295 | | | Apply-To-Redirect-Ref | permanent | | 4437 | RFC 4437 | | | Authentication-Control | permanent | | 8053 | RFC 8053, Section 4 | | | Authentication-Info | permanent | | 9110 | RFC 9110, Section 11.6.3 | | | Authorization | permanent | | 9110 | RFC 9110, Section 11.6.2 | | | Available-Dictionary | permanent | Item | 9842 | RFC 9842, Section 2.2 | | | C-Ext | obsoleted | | 2774 | RFC 2774 | [Status change of HTTP experiments to Historic] | | C-Man | obsoleted | | 2774 | RFC 2774 | [Status change of HTTP experiments to Historic] | | C-Opt | obsoleted | | 2774 | RFC 2774 | [Status change of HTTP experiments to Historic] | | C-PEP | obsoleted | | | | [Status change of HTTP experiments to Historic] | | C-PEP-Info | deprecated | | | | [Status change of HTTP experiments to Historic] | | CDN-Cache-Control | permanent | Dictionary | 9213 | RFC 9213 | Cache directives targeted at content delivery networks | | CDN-Loop | permanent | | 8586 | RFC 8586 | | | CMCD-Object | provisional | | | CTA | | | CMCD-Request | provisional | | | CTA | | | CMCD-Session | provisional | | | CTA | | | CMCD-Status | provisional | | | CTA | | | CMSD-Dynamic | provisional | | | CTA | | | CMSD-Static | provisional | | | CTA | | | CTA-Common-Access-Token | provisional | | | CTA | | | Cache-Control | permanent | | 9111 | RFC 9111, Section 5.2 | | | Cache-Group-Invalidation | permanent | List | 9875 | RFC 9875 | | | Cache-Groups | permanent | List | 9875 | RFC 9875 | | | Cache-Status | permanent | List | 9211 | RFC 9211 | | | Cal-Managed-ID | permanent | | 8607 | RFC 8607, Section 5.1 | | | CalDAV-Timezones | permanent | | 7809 | RFC 7809, Section 7.1 | | | Capsule-Protocol | permanent | Item | 9297 | RFC 9297 | | | Cert-Not-After | permanent | | 8739 | RFC 8739, Section 3.3 | | | Cert-Not-Before | permanent | | 8739 | RFC 8739, Section 3.3 | | | Clear-Site-Data | permanent | | | | | | Client-Cert | permanent | Item | 9440 | RFC 9440, Section 2 | | | Client-Cert-Chain | permanent | List | 9440 | RFC 9440, Section 2 | | | Close | permanent | | 9112 | RFC 9112, Section 9.6 | (reserved) | | Concealed-Auth-Export | permanent | Item | 9729 | RFC 9729 | | | Configuration-Context | provisional | | | | | | Connect-UDP-Bind | permanent | Item | | | | | Connection | permanent | | 9110 | RFC 9110, Section 7.6.1 | | | Content-Base | obsoleted | | 2068 | RFC 2068 | Obsoleted by [RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1] | | Content-Digest | permanent | Dictionary | 9530 | RFC 9530, Section 2 | | | Content-Disposition | permanent | | 6266 | RFC 6266 | | | Content-Encoding | permanent | | 9110 | RFC 9110, Section 8.4 | | | Content-ID | deprecated | | | | | | Content-Language | permanent | | 9110 | RFC 9110, Section 8.5 | | | Content-Length | permanent | | 9110 | RFC 9110, Section 8.6 | | | Content-Location | permanent | | 9110 | RFC 9110, Section 8.7 | | | Content-MD5 | obsoleted | | 2616 | RFC 2616, Section 14.15 | Obsoleted by [RFC 7231, Appendix B: Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content] | | Content-Range | permanent | | 9110 | RFC 9110, Section 14.4 | | | Content-Script-Type | obsoleted | | | HTML 4.01 Specification | | | Content-Security-Policy | permanent | | | | | | Content-Security-Policy-Report-Only | permanent | | | | | | Content-Style-Type | obsoleted | | | HTML 4.01 Specification | | | Content-Type | permanent | | 9110 | RFC 9110, Section 8.3 | | | Content-Version | obsoleted | | 2068 | RFC 2068 | | | Cookie | permanent | | 6265 | | | | Cookie2 | obsoleted | | 2965 | RFC 2965 | Obsoleted by [RFC 6265: HTTP State Management Mechanism] | | Cross-Origin-Embedder-Policy | permanent | Item | | HTML | | | Cross-Origin-Embedder-Policy-Report-Only | permanent | Item | | HTML | | | Cross-Origin-Opener-Policy | permanent | Item | | HTML | | | Cross-Origin-Opener-Policy-Report-Only | permanent | Item | | HTML | | | Cross-Origin-Resource-Policy | permanent | | | | | | DASL | permanent | | 5323 | RFC 5323 | | | DAV | permanent | | 4918 | RFC 4918 | | | DPoP | permanent | | 9449 | RFC 9449 | | | DPoP-Nonce | permanent | | 9449 | RFC 9449 | | | Date | permanent | | 9110 | RFC 9110, Section 6.6.1 | | | Default-Style | obsoleted | | | HTML 4.01 Specification | | | Delta-Base | permanent | | 3229 | RFC 3229 | | | Deprecation | permanent | Item | 9745 | RFC 9745, Section 2 | | | Depth | permanent | | 4918 | RFC 4918 | | | Derived-From | obsoleted | | 2068 | RFC 2068 | | | Destination | permanent | | 4918 | RFC 4918 | | | Detached-JWS | permanent | | 9635 | RFC 9635 | | | Dictionary-ID | permanent | Item | 9842 | RFC 9842, Section 2.3 | | | Differential-ID | deprecated | | | | | | Digest | obsoleted | | 3230 | RFC 3230 | Obsoleted by [RFC 9530, Section 1.3: Digest Fields] | | EDIINT-Features | provisional | | 6017 | RFC 6017 | | | ETag | permanent | | 9110 | RFC 9110, Section 8.8.3 | | | Early-Data | permanent | | 8470 | RFC 8470 | | | Expect | permanent | | 9110 | RFC 9110, Section 10.1.1 | | | Expect-CT | deprecated | | 9163 | RFC 9163 | Obsoleted by [IESG]; [HTTPBIS] | | Expires | permanent | | 9111 | RFC 9111, Section 5.3 | | | Ext | obsoleted | | 2774 | RFC 2774 | [Status change of HTTP experiments to Historic] | | Forwarded | permanent | | 7239 | RFC 7239 | | | From | permanent | | 9110 | RFC 9110, Section 10.1.2 | | | GetProfile | obsoleted | | | | | | HTTP2-Settings | obsoleted | | 7540 | RFC 7540, Section 3.2.1 | Obsolete; see [Section 11.1 of RFC 9113] | | Hobareg | permanent | | 7486 | RFC 7486, Section 6.1.1 | | | Host | permanent | | 9110 | RFC 9110, Section 7.2 | | | IM | permanent | | 3229 | RFC 3229 | | | If | permanent | | 4918 | RFC 4918 | | | If-Match | permanent | | 9110 | RFC 9110, Section 13.1.1 | | | If-Modified-Since | permanent | | 9110 | RFC 9110, Section 13.1.3 | | | If-None-Match | permanent | | 9110 | RFC 9110, Section 13.1.2 | | | If-Range | permanent | | 9110 | RFC 9110, Section 13.1.5 | | | If-Schedule-Tag-Match | permanent | | 6338 | RFC 6338 | | | If-Unmodified-Since | permanent | | 9110 | RFC 9110, Section 13.1.4 | | | Include-Referred-Token-Binding-ID | permanent | | 8473 | RFC 8473 | | | Incremental | permanent | Item | 10036 | RFC 10036 | | | Isolation | provisional | | | OASIS | | | Keep-Alive | permanent | | 2068 | RFC 2068 | | | Label | permanent | | 3253 | RFC 3253 | | | Last-Event-ID | permanent | | | HTML | | | Last-Modified | permanent | | 9110 | RFC 9110, Section 8.8.2 | | | Link | permanent | | 8288 | RFC 8288 | | | Link-Template | permanent | | 9652 | RFC 9652 | | | Location | permanent | | 9110 | RFC 9110, Section 10.2.2 | | | Lock-Token | permanent | | 4918 | RFC 4918 | | | MIME-Version | permanent | | 9112 | RFC 9112, Appendix B.1 | | | Man | obsoleted | | 2774 | RFC 2774 | [Status change of HTTP experiments to Historic] | | Max-Forwards | permanent | | 9110 | RFC 9110, Section 7.6.2 | | | Memento-Datetime | permanent | | 7089 | RFC 7089 | | | Meter | permanent | | 2227 | RFC 2227 | | | Method-Check | obsoleted | | | | | | Method-Check-Expires | obsoleted | | | | | | NEL | permanent | | | | | | Negotiate | permanent | | 2295 | RFC 2295 | | | No-Vary-Search | permanent | Dictionary | | | | | OData-EntityId | permanent | | | OASIS | | | OData-Isolation | permanent | | | OASIS | | | OData-MaxVersion | permanent | | | OASIS | | | OData-Version | permanent | | | OASIS | | | OSCORE | permanent | | 8613 | RFC 8613, Section 11.1 | | | OSLC-Core-Version | permanent | | | OASIS Project Specification 01; OASIS | | | Opt | obsoleted | | 2774 | RFC 2774 | [Status change of HTTP experiments to Historic] | | Optional-WWW-Authenticate | permanent | | 8053 | RFC 8053, Section 3 | | | Ordering-Type | permanent | | 3648 | RFC 3648 | | | Origin | permanent | | 6454 | RFC 6454 | | | Origin-Agent-Cluster | permanent | Item | | HTML | | | Overwrite | permanent | | 4918 | RFC 4918 | | | P3P | obsoleted | | | | | | PEP | obsoleted | | | | | | PEP-Info | obsoleted | | | | | | PICS-Label | obsoleted | | | | | | Permissions-Policy | provisional | | | | | | Ping-From | permanent | | | HTML | | | Ping-To | permanent | | | HTML | | | Position | permanent | | 3648 | RFC 3648 | | | Pragma | deprecated | | 9111 | RFC 9111, Section 5.4 | | | Prefer | permanent | | 7240 | RFC 7240 | | | Preference-Applied | permanent | | 7240 | RFC 7240 | | | Priority | permanent | Dictionary | 9218 | RFC 9218 | | | ProfileObject | obsoleted | | | | | | Protocol | obsoleted | | | | | | Protocol-Info | deprecated | | | | | | Protocol-Query | deprecated | | | | | | Protocol-Request | obsoleted | | | | | | Proxy-Authenticate | permanent | | 9110 | RFC 9110, Section 11.7.1 | | | Proxy-Authentication-Info | permanent | | 9110 | RFC 9110, Section 11.7.3 | | | Proxy-Authorization | permanent | | 9110 | RFC 9110, Section 11.7.2 | | | Proxy-Features | obsoleted | | | | | | Proxy-Instruction | obsoleted | | | | | | Proxy-Public-Address | permanent | List | | | | | Proxy-Status | permanent | List | 9209 | RFC 9209 | | | Public | obsoleted | | 2068 | RFC 2068 | | | Public-Key-Pins | permanent | | 7469 | RFC 7469 | | | Public-Key-Pins-Report-Only | permanent | | 7469 | RFC 7469 | | | Range | permanent | | 9110 | RFC 9110, Section 14.2 | | | Redirect-Ref | permanent | | 4437 | RFC 4437 | | | Referer | permanent | | 9110 | RFC 9110, Section 10.1.3 | | | Referer-Root | obsoleted | | | | | | Referrer-Policy | permanent | | | | The header name does not share the HTTP Referer header's misspelling. | | Refresh | permanent | | | HTML | | | Repeatability-Client-ID | provisional | | | OASIS | | | Repeatability-First-Sent | provisional | | | OASIS | | | Repeatability-Request-ID | provisional | | | OASIS | | | Repeatability-Result | provisional | | | OASIS | | | Replay-Nonce | permanent | | 8555 | RFC 8555, Section 6.5.1 | | | Reporting-Endpoints | provisional | | | | | | Repr-Digest | permanent | Dictionary | 9530 | RFC 9530, Section 3 | | | Retry-After | permanent | | 9110 | RFC 9110, Section 10.2.3 | | | SLUG | permanent | | 5023 | RFC 5023 | | | Safe | obsoleted | | 2310 | RFC 2310 | [Status change of HTTP experiments to Historic] | | Schedule-Reply | permanent | | 6638 | RFC 6638 | | | Schedule-Tag | permanent | | 6338 | RFC 6338 | | | Sec-Fetch-Dest | permanent | Item | | https://www.w3.org/TR/fetch-metadata/#sec-fetch-dest-header | | | Sec-Fetch-Mode | permanent | Item | | https://www.w3.org/TR/fetch-metadata/#sec-fetch-mode-header | | | Sec-Fetch-Site | permanent | Item | | https://www.w3.org/TR/fetch-metadata/#sec-fetch-site-header | | | Sec-Fetch-Storage-Access | provisional | Token | | https://privacycg.github.io/storage-access-headers | | | Sec-Fetch-User | permanent | Item | | https://www.w3.org/TR/fetch-metadata/#sec-fetch-user-header | | | Sec-GPC | provisional | | | | | | Sec-Purpose | permanent | | | | Intended to replace the (not registered) Purpose and x-moz headers. | | Sec-Token-Binding | permanent | | 8473 | RFC 8473 | | | Sec-WebSocket-Accept | permanent | | 6455 | RFC 6455 | | | Sec-WebSocket-Extensions | permanent | | 6455 | RFC 6455 | | | Sec-WebSocket-Key | permanent | | 6455 | RFC 6455 | | | Sec-WebSocket-Protocol | permanent | | 6455 | RFC 6455 | | | Sec-WebSocket-Version | permanent | | 6455 | RFC 6455 | | | Security-Scheme | obsoleted | | 2660 | RFC 2660 | [Status change of HTTP experiments to Historic] | | Server | permanent | | 9110 | RFC 9110, Section 10.2.4 | | | Server-Timing | permanent | | | | | | Set-Cookie | permanent | | 6265 | | | | Set-Cookie2 | obsoleted | | 2965 | RFC 2965 | Obsoleted by [RFC 6265: HTTP State Management Mechanism] | | Set-Txn | permanent | | 9967 | RFC 9967, Section 3 | | | SetProfile | obsoleted | | | | | | Signature | permanent | Dictionary | 9421 | RFC 9421, Section 4.2 | | | Signature-Input | permanent | Dictionary | 9421 | RFC 9421, Section 4.1 | | | SoapAction | permanent | | | | | | Status-URI | permanent | | 2518 | RFC 2518 | | | Strict-Transport-Security | permanent | | 6797 | RFC 6797 | | | Sunset | permanent | | 8594 | RFC 8594 | | | Surrogate-Capability | provisional | | | | | | Surrogate-Control | provisional | | | | | | TCN | permanent | | 2295 | RFC 2295 | | | TE | permanent | | 9110 | RFC 9110, Section 10.1.4 | | | TTL | permanent | | 8030 | RFC 8030, Section 5.2 | | | Timeout | permanent | | 4918 | RFC 4918 | | | Timing-Allow-Origin | provisional | | | | | | Topic | permanent | | 8030 | RFC 8030, Section 5.4 | | | Traceparent | permanent | | | | | | Tracestate | permanent | | | | | | Trailer | permanent | | 9110 | RFC 9110, Section 6.6.2 | | | Transfer-Encoding | permanent | | 9112 | RFC 9112, Section 6.1 | | | URI | obsoleted | | 2068 | RFC 2068 | | | Unencoded-Digest | permanent | Dictionary | | | | | Upgrade | permanent | | 9110 | RFC 9110, Section 7.8 | | | Urgency | permanent | | 8030 | RFC 8030, Section 5.3 | | | Use-As-Dictionary | permanent | Dictionary | 9842 | RFC 9842, Section 2.1 | | | User-Agent | permanent | | 9110 | RFC 9110, Section 10.1.5 | | | Variant-Vary | permanent | | 2295 | RFC 2295 | | | Vary | permanent | | 9110 | RFC 9110, Section 12.5.5 | | | Via | permanent | | 9110 | RFC 9110, Section 7.6.3 | | | WWW-Authenticate | permanent | | 9110 | RFC 9110, Section 11.6.1 | | | Want-Content-Digest | permanent | Dictionary | 9530 | RFC 9530, Section 4 | | | Want-Digest | obsoleted | | 3230 | RFC 3230 | Obsoleted by [RFC 9530, Section 1.3: Digest Fields] | | Want-Repr-Digest | permanent | Dictionary | 9530 | RFC 9530, Section 4 | | | Want-Unencoded-Digest | permanent | Dictionary | | | | | Warning | obsoleted | | 9111 | RFC 9111, Section 5.5 | | | X-Content-Type-Options | permanent | | | | | | X-Frame-Options | permanent | | | HTML | | Source: https://aidb.si/d/http-header-fields — Source: Internet Assigned Numbers Authority (IANA), HTTP Field Name Registry.