   Internet Assigned Numbers Authority

                                                Hypertext Transfer Protocol (HTTP) Field Name Registry

   Created
           2021-10-01

   Last Updated
           2022-06-10

   Available Formats
           [IMG]
           XML [IMG]
           HTML [IMG]
           Plain text

   Registry included below

     * Hypertext Transfer Protocol (HTTP) Field Name Registry

Hypertext Transfer Protocol (HTTP) Field Name Registry

   Registration Procedure(s)

 Specification Required for Permanent registrations,
 Expert Review for Provisional registrations.


   Expert(s)

 Mark Nottingham, Roy Fielding

   Reference
           [RFC9110]

   Note

 See Section 16.3 of [RFC9110] for more
 information on defining and registering new HTTP Fields.


   Note

 New field names, along with changes to existing ones, can be
 requested using the [registry interface] or the mailing list
 defined in [RFC9110].


   Available Formats
           [IMG]
           CSV

                 Field Name                          Template              Status                          Reference                         Comments
  A-IM                                                                   permanent   [RFC 3229: Delta encoding in HTTP]
  Accept                                                                 permanent   [RFC9110, Section 12.5.1: HTTP Semantics]
  Accept-Additions                                                       permanent   [RFC 2324: Hyper Text Coffee Pot Control Protocol
                                                                                     (HTCPCP/1.0)]
  Accept-CH                                                              permanent   [RFC 8942, Section 3.1: HTTP Client Hints]
  Accept-Charset                                                         deprecated  [RFC9110, Section 12.5.2: HTTP Semantics]
  Accept-Datetime                                                        permanent   [RFC 7089: HTTP Framework for Time-Based Access to
                                                                                     Resource States -- Memento]
  Accept-Encoding                                                        permanent   [RFC9110, Section 12.5.3: HTTP Semantics]
  Accept-Features                                                        permanent   [RFC 2295: Transparent Content Negotiation in HTTP]
  Accept-Language                                                        permanent   [RFC9110, Section 12.5.4: HTTP Semantics]
  Accept-Patch                                                           permanent   [RFC 5789: PATCH Method for HTTP]
  Accept-Post                              perm/accept-post              permanent   [Linked Data Platform 1.0]
  Accept-Ranges                                                          permanent   [RFC9110, Section 14.3: HTTP Semantics]
  Access-Control                                                         obsoleted   [Access Control for Cross-site Requests]
  Access-Control-Allow-Credentials                                       permanent   [Fetch]
  Access-Control-Allow-Headers                                           permanent   [Fetch]
  Access-Control-Allow-Methods                                           permanent   [Fetch]
  Access-Control-Allow-Origin                                            permanent   [Fetch]
  Access-Control-Expose-Headers                                          permanent   [Fetch]
  Access-Control-Max-Age                                                 permanent   [Fetch]
  Access-Control-Request-Headers                                         permanent   [Fetch]
  Access-Control-Request-Method                                          permanent   [Fetch]
  Age                                                                    permanent   [RFC9111, Section 5.1: HTTP Caching]
  Allow                                                                  permanent   [RFC9110, Section 10.2.1: HTTP Semantics]
  ALPN                                                                   permanent   [RFC 7639, Section 2: The ALPN HTTP Header Field]
  Alt-Svc                                                                permanent   [RFC 7838: HTTP Alternative Services]
  Alt-Used                                                               permanent   [RFC 7838: HTTP Alternative Services]
  Alternates                                                             permanent   [RFC 2295: Transparent Content Negotiation in HTTP]
  AMP-Cache-Transform                                                    provisional [AMP-Cache-Transform HTTP request header]
  Apply-To-Redirect-Ref                                                  permanent   [RFC 4437: Web Distributed Authoring and Versioning
                                                                                     (WebDAV) Redirect Reference Resources]
  Authentication-Control                                                 permanent   [RFC 8053, Section 4: HTTP Authentication Extensions
                                                                                     for Interactive Clients]
  Authentication-Info                                                    permanent   [RFC9110, Section 11.6.3: HTTP Semantics]
  Authorization                                                          permanent   [RFC9110, Section 11.6.2: HTTP Semantics]
  C-Ext                                                                  obsoleted   [RFC 2774: An HTTP Extension
                                                                                     Framework][status-change-http-experiments-to-historic]
  C-Man                                                                  obsoleted   [RFC 2774: An HTTP Extension
                                                                                     Framework][status-change-http-experiments-to-historic]
  C-Opt                                                                  obsoleted   [RFC 2774: An HTTP Extension
                                                                                     Framework][status-change-http-experiments-to-historic]
  C-PEP                                                                  obsoleted   [PEP - an Extension Mechanism for
                                                                                     HTTP][status-change-http-experiments-to-historic]
  C-PEP-Info                                                             deprecated  [PEP - an Extension Mechanism for
                                                                                     HTTP][status-change-http-experiments-to-historic]
  Cache-Control                                                          permanent   [RFC9111, Section 5.2]
  Cache-Status                                                           permanent   [RFC9211: The Cache-Status HTTP Response Header Field]
  Cal-Managed-ID                                                         permanent   [RFC 8607, Section 5.1: Calendaring Extensions to
                                                                                     WebDAV (CalDAV): Managed Attachments]
  CalDAV-Timezones                                                       permanent   [RFC 7809, Section 7.1: Calendaring Extensions to
                                                                                     WebDAV (CalDAV): Time Zones by Reference]
                                                                                                                                            Cache
                                                                                                                                            directives
  CDN-Cache-Control                                                      permanent   [RFC9213: Targeted HTTP Cache Control]                 targeted
                                                                                                                                            at content
                                                                                                                                            delivery
                                                                                                                                            networks
  CDN-Loop                                                               permanent   [RFC 8586: Loop Detection in Content Delivery Networks
                                                                                     (CDNs)]
                                                                                     [RFC 8739, Section 3.3: Support for Short-Term,
  Cert-Not-After                                                         permanent   Automatically Renewed (STAR) Certificates in the
                                                                                     Automated Certificate Management Environment (ACME)]
                                                                                     [RFC 8739, Section 3.3: Support for Short-Term,
  Cert-Not-Before                                                        permanent   Automatically Renewed (STAR) Certificates in the
                                                                                     Automated Certificate Management Environment (ACME)]
  Clear-Site-Data                                                        permanent   [Clear Site Data]
  Close                                                                  permanent   [RFC9112, Section 9.6: HTTP/1.1]                       (reserved)
  Configuration-Context                                                  provisional [OSLC Configuration Management Version 1.0. Part 3:
                                                                                     Configuration Specification]
  Connection                                                             permanent   [RFC9110, Section 7.6.1: HTTP Semantics]
                                                                                     [RFC 2068: Hypertext Transfer Protocol --
  Content-Base                                                           obsoleted   HTTP/1.1][RFC 2616: Hypertext Transfer Protocol --
                                                                                     HTTP/1.1]
  Content-Disposition                                                    permanent   [RFC 6266: Use of the Content-Disposition Header Field
                                                                                     in the Hypertext Transfer Protocol (HTTP)]
  Content-Encoding                                                       permanent   [RFC9110, Section 8.4: HTTP Semantics]
  Content-ID                                                             permanent   [The HTTP Distribution and Replication Protocol]
  Content-Language                                                       permanent   [RFC9110, Section 8.5: HTTP Semantics]
  Content-Length                                                         permanent   [RFC9110, Section 8.6: HTTP Semantics]
  Content-Location                                                       permanent   [RFC9110, Section 8.7: HTTP Semantics]
                                                                                     [RFC 2616, Section 14.15: Hypertext Transfer Protocol
  Content-MD5                                                            obsoleted   -- HTTP/1.1][RFC 7231, Appendix B: Hypertext Transfer
                                                                                     Protocol (HTTP/1.1): Semantics and Content]
  Content-Range                                                          permanent   [RFC9110, Section 14.4: HTTP Semantics]
  Content-Script-Type                                                    obsoleted   [HTML 4.01 Specification]
  Content-Security-Policy                                                permanent   [Content Security Policy Level 3]
  Content-Security-Policy-Report-Only                                    permanent   [Content Security Policy Level 3]
  Content-Style-Type                                                     obsoleted   [HTML 4.01 Specification]
  Content-Type                                                           permanent   [RFC9110, Section 8.3: HTTP Semantics]
  Content-Version                                                        obsoleted   [RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1]
  Cookie                                                                 permanent   [RFC 6265: HTTP State Management Mechanism]
  Cookie2                                                                obsoleted   [RFC 2965: HTTP State Management Mechanism][RFC 6265:
                                                                                     HTTP State Management Mechanism]
  Cross-Origin-Embedder-Policy                                           permanent   [HTML]
  Cross-Origin-Embedder-Policy-Report-Only                               permanent   [HTML]
  Cross-Origin-Opener-Policy                                             permanent   [HTML]
  Cross-Origin-Opener-Policy-Report-Only                                 permanent   [HTML]
  Cross-Origin-Resource-Policy                                           permanent   [Fetch]
  DASL                                                                   permanent   [RFC 5323: Web Distributed Authoring and Versioning
                                                                                     (WebDAV) SEARCH]
  Date                                                                   permanent   [RFC9110, Section 6.6.1: HTTP Semantics]
  DAV                                                                    permanent   [RFC 4918: HTTP Extensions for Web Distributed
                                                                                     Authoring and Versioning (WebDAV)]
  Default-Style                                                          obsoleted   [HTML 4.01 Specification]
  Delta-Base                                                             permanent   [RFC 3229: Delta encoding in HTTP]
  Depth                                                                  permanent   [RFC 4918: HTTP Extensions for Web Distributed
                                                                                     Authoring and Versioning (WebDAV)]
  Derived-From                                                           obsoleted   [RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1]
  Destination                                                            permanent   [RFC 4918: HTTP Extensions for Web Distributed
                                                                                     Authoring and Versioning (WebDAV)]
  Differential-ID                                                        permanent   [The HTTP Distribution and Replication Protocol]
  Digest                                                                 permanent   [RFC 3230: Instance Digests in HTTP]
  Early-Data                                                             permanent   [RFC 8470: Using Early Data in HTTP]
  EDIINT-Features                                                        provisional [RFC 6017: Electronic Data Interchange - Internet
                                                                                     Integration (EDIINT) Features Header Field]
  ETag                                                                   permanent   [RFC9110, Section 8.8.3: HTTP Semantics]
  Expect                                                                 permanent   [RFC9110, Section 10.1.1: HTTP Semantics]
  Expect-CT                                                              permanent   [RFC9163: Expect-CT Extension for HTTP]
  Expires                                                                permanent   [RFC9111, Section 5.3: HTTP Caching]
  Ext                                                                    obsoleted   [RFC 2774: An HTTP Extension
                                                                                     Framework][status-change-http-experiments-to-historic]
  Forwarded                                                              permanent   [RFC 7239: Forwarded HTTP Extension]
  From                                                                   permanent   [RFC9110, Section 10.1.2: HTTP Semantics]
  GetProfile                                                             obsoleted   [Implementation of OPS Over HTTP]
  Hobareg                                                                permanent   [RFC 7486, Section 6.1.1: HTTP Origin-Bound
                                                                                     Authentication (HOBA)]
  Host                                                                   permanent   [RFC9110, Section 7.2: HTTP Semantics]
                                                                                                                                            Obsolete;
                                                                                     [RFC 7540, Section 3.2.1: Hypertext Transfer Protocol  see
  HTTP2-Settings                                                         obsoleted   Version 2 (HTTP/2)]                                    Section
                                                                                                                                            11.1 of
                                                                                                                                            [RFC9113]
  If                                                                     permanent   [RFC 4918: HTTP Extensions for Web Distributed
                                                                                     Authoring and Versioning (WebDAV)]
  If-Match                                                               permanent   [RFC9110, Section 13.1.1: HTTP Semantics]
  If-Modified-Since                                                      permanent   [RFC9110, Section 13.1.3: HTTP Semantics]
  If-None-Match                                                          permanent   [RFC9110, Section 13.1.2: HTTP Semantics]
  If-Range                                                               permanent   [RFC9110, Section 13.1.5: HTTP Semantics]
  If-Schedule-Tag-Match                                                  permanent   [ RFC 6338: Scheduling Extensions to CalDAV]
  If-Unmodified-Since                                                    permanent   [RFC9110, Section 13.1.4: HTTP Semantics]
  IM                                                                     permanent   [RFC 3229: Delta encoding in HTTP]
  Include-Referred-Token-Binding-ID                                      permanent   [RFC 8473: Token Binding over HTTP]
  Isolation                                prov/isolation                provisional [OData Version 4.01 Part 1:
                                                                                     Protocol][OASIS][Chet_Ensign]
  Keep-Alive                                                             permanent   [RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1]
  Label                                                                  permanent   [RFC 3253: Versioning Extensions to WebDAV: (Web
                                                                                     Distributed Authoring and Versioning)]
  Last-Event-ID                                                          permanent   [HTML]
  Last-Modified                                                          permanent   [RFC9110, Section 8.8.2: HTTP Semantics]
  Link                                                                   permanent   [RFC 8288: Web Linking]
  Location                                                               permanent   [RFC9110, Section 10.2.2: HTTP Semantics]
  Lock-Token                                                             permanent   [RFC 4918: HTTP Extensions for Web Distributed
                                                                                     Authoring and Versioning (WebDAV)]
  Man                                                                    obsoleted   [RFC 2774: An HTTP Extension
                                                                                     Framework][status-change-http-experiments-to-historic]
  Max-Forwards                                                           permanent   [RFC9110, Section 7.6.2: HTTP Semantics]
  Memento-Datetime                                                       permanent   [RFC 7089: HTTP Framework for Time-Based Access to
                                                                                     Resource States -- Memento]
  Meter                                                                  permanent   [RFC 2227: Simple Hit-Metering and Usage-Limiting for
                                                                                     HTTP]
  Method-Check                                                           obsoleted   [Access Control for Cross-site Requests]
  Method-Check-Expires                                                   obsoleted   [Access Control for Cross-site Requests]
  MIME-Version                                                           permanent   [RFC9112, Appendix B.1: HTTP/1.1]
  Negotiate                                                              permanent   [RFC 2295: Transparent Content Negotiation in HTTP]
  OData-EntityId                           perm/odata-entityid           permanent   [OData Version 4.01 Part 1:
                                                                                     Protocol][OASIS][Chet_Ensign]
  OData-Isolation                          perm/odata-isolation          permanent   [OData Version 4.01 Part 1:
                                                                                     Protocol][OASIS][Chet_Ensign]
  OData-MaxVersion                         perm/odata-maxversion         permanent   [OData Version 4.01 Part 1:
                                                                                     Protocol][OASIS][Chet_Ensign]
  OData-Version                            perm/odata-version            permanent   [OData Version 4.01 Part 1:
                                                                                     Protocol][OASIS][Chet_Ensign]
  Opt                                                                    obsoleted   [RFC 2774: An HTTP Extension
                                                                                     Framework][status-change-http-experiments-to-historic]
  Optional-WWW-Authenticate                                              permanent   [RFC 8053, Section 3: HTTP Authentication Extensions
                                                                                     for Interactive Clients]
  Ordering-Type                                                          permanent   [RFC 3648: Web Distributed Authoring and Versioning
                                                                                     (WebDAV) Ordered Collections Protocol]
  Origin                                                                 permanent   [RFC 6454: The Web Origin Concept]
  Origin-Agent-Cluster                                                   permanent   [HTML]
  OSCORE                                                                 permanent   [RFC 8613, Section 11.1: Object Security for
                                                                                     Constrained RESTful Environments (OSCORE)]
  OSLC-Core-Version                                                      permanent   [OASIS Project Specification 01][OASIS][Chet_Ensign]
  Overwrite                                                              permanent   [RFC 4918: HTTP Extensions for Web Distributed
                                                                                     Authoring and Versioning (WebDAV)]
  P3P                                                                    obsoleted   [The Platform for Privacy Preferences 1.0 (P3P1.0)
                                                                                     Specification]
  PEP                                                                    obsoleted   [PEP - an Extension Mechanism for HTTP]
  Pep-Info                                                               obsoleted   [PEP - an Extension Mechanism for HTTP]
  PICS-Label                                                             obsoleted   [PICS Label Distribution Label Syntax and
                                                                                     Communication Protocols]
  Ping-From                                                              permanent   [HTML]
  Ping-To                                                                permanent   [HTML]
  Position                                                               permanent   [RFC 3648: Web Distributed Authoring and Versioning
                                                                                     (WebDAV) Ordered Collections Protocol]
  Pragma                                                                 deprecated  [RFC9111, Section 5.4: HTTP Caching]
  Prefer                                                                 permanent   [RFC 7240: Prefer Header for HTTP]
  Preference-Applied                                                     permanent   [RFC 7240: Prefer Header for HTTP]
  Priority                                                               permanent   [RFC9218: Extensible Prioritization Scheme for HTTP]
  ProfileObject                                                          obsoleted   [Implementation of OPS Over HTTP]
  Protocol                                                               obsoleted   [PICS Label Distribution Label Syntax and
                                                                                     Communication Protocols]
  Protocol-Info                                                          deprecated  [White Paper: Joint Electronic Payment Initiative]
  Protocol-Query                                                         deprecated  [White Paper: Joint Electronic Payment Initiative]
  Protocol-Request                                                       obsoleted   [PICS Label Distribution Label Syntax and
                                                                                     Communication Protocols]
  Proxy-Authenticate                                                     permanent   [RFC9110, Section 11.7.1: HTTP Semantics]
  Proxy-Authentication-Info                                              permanent   [RFC9110, Section 11.7.3: HTTP Semantics]
  Proxy-Authorization                                                    permanent   [RFC9110, Section 11.7.2: HTTP Semantics]
  Proxy-Features                                                         obsoleted   [Notification for Proxy Caches]
  Proxy-Instruction                                                      obsoleted   [Notification for Proxy Caches]
  Proxy-Status                                                           permanent   [RFC9209: The Proxy-Status HTTP Response Header Field]
  Public                                                                 obsoleted   [RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1]
  Public-Key-Pins                                                        permanent   [RFC 7469: Public Key Pinning Extension for HTTP]
  Public-Key-Pins-Report-Only                                            permanent   [RFC 7469: Public Key Pinning Extension for HTTP]
  Range                                                                  permanent   [RFC9110, Section 14.2: HTTP Semantics]
  Redirect-Ref                                                           permanent   [RFC 4437: Web Distributed Authoring and Versioning
                                                                                     (WebDAV) Redirect Reference Resources]
  Referer                                                                permanent   [RFC9110, Section 10.1.3: HTTP Semantics]
  Referer-Root                                                           obsoleted   [Access Control for Cross-site Requests]
  Refresh                                                                permanent   [HTML]
  Repeatability-Client-ID                  prov/repeatability-client-id  provisional [Repeatable Requests Version 1.0][OASIS][Chet_Ensign]
  Repeatability-First-Sent                 prov/repeatability-first-sent provisional [Repeatable Requests Version 1.0][OASIS][Chet_Ensign]
  Repeatability-Request-ID                 prov/repeatability-request-id provisional [Repeatable Requests Version 1.0][OASIS][Chet_Ensign]
  Repeatability-Result                     prov/repeatability-result     provisional [Repeatable Requests Version 1.0][OASIS][Chet_Ensign]
  Replay-Nonce                                                           permanent   [RFC 8555, Section 6.5.1: Automatic Certificate
                                                                                     Management Environment (ACME)]
  Retry-After                                                            permanent   [RFC9110, Section 10.2.3: HTTP Semantics]
  Safe                                                                   obsoleted   [RFC 2310: The Safe Response Header
                                                                                     Field][status-change-http-experiments-to-historic]
  Schedule-Reply                                                         permanent   [RFC 6638: Scheduling Extensions to CalDAV]
  Schedule-Tag                                                           permanent   [RFC 6338: Scheduling Extensions to CalDAV]
  Sec-GPC                                                                Provisional [Global Privacy Control (GPC)]
  Sec-Token-Binding                                                      permanent   [RFC 8473: Token Binding over HTTP]
  Sec-WebSocket-Accept                                                   permanent   [RFC 6455: The WebSocket Protocol]
  Sec-WebSocket-Extensions                                               permanent   [RFC 6455: The WebSocket Protocol]
  Sec-WebSocket-Key                                                      permanent   [RFC 6455: The WebSocket Protocol]
  Sec-WebSocket-Protocol                                                 permanent   [RFC 6455: The WebSocket Protocol]
  Sec-WebSocket-Version                                                  permanent   [RFC 6455: The WebSocket Protocol]
  Security-Scheme                                                        obsoleted   [RFC 2660: The Secure HyperText Transfer
                                                                                     Protocol][status-change-http-experiments-to-historic]
  Server                                                                 permanent   [RFC9110, Section 10.2.4: HTTP Semantics]
  Server-Timing                                                          permanent   [Server Timing]
  Set-Cookie                                                             permanent   [RFC 6265: HTTP State Management Mechanism]
  Set-Cookie2                                                            obsoleted   [RFC 2965: HTTP State Management Mechanism][RFC 6265:
                                                                                     HTTP State Management Mechanism]
  SetProfile                                                             obsoleted   [Implementation of OPS Over HTTP]
  SLUG                                                                   permanent   [RFC 5023: The Atom Publishing Protocol]
  SoapAction                                                             permanent   [Simple Object Access Protocol (SOAP) 1.1]
  Status-URI                                                             permanent   [RFC 2518: HTTP Extensions for Distributed Authoring
                                                                                     -- WEBDAV]
  Strict-Transport-Security                                              permanent   [RFC 6797: HTTP Strict Transport Security (HSTS)]
  Sunset                                                                 permanent   [RFC 8594: The Sunset HTTP Header Field]
  Surrogate-Capability                                                   permanent   [Edge Architecture Specification]
  Surrogate-Control                                                      permanent   [Edge Architecture Specification]
  TCN                                                                    permanent   [RFC 2295: Transparent Content Negotiation in HTTP]
  TE                                                                     permanent   [RFC9110, Section 10.1.4: HTTP Semantics]
  Timeout                                                                permanent   [RFC 4918: HTTP Extensions for Web Distributed
                                                                                     Authoring and Versioning (WebDAV)]
  Timing-Allow-Origin                      prov/timing-allow-origin      provisional [Resource Timing Level 1]
  Topic                                                                  permanent   [RFC 8030, Section 5.4: Generic Event Delivery Using
                                                                                     HTTP Push]
  Traceparent                                                            permanent   [Trace Context]
  Tracestate                                                             permanent   [Trace Context]
  Trailer                                                                permanent   [RFC9110, Section 6.6.2: HTTP Semantics]
  Transfer-Encoding                                                      permanent   [RFC9112, Section 6.1: HTTP Semantics]
  TTL                                                                    permanent   [RFC 8030, Section 5.2: Generic Event Delivery Using
                                                                                     HTTP Push]
  Upgrade                                                                permanent   [RFC9110, Section 7.8: HTTP Semantics]
  Urgency                                                                permanent   [RFC 8030, Section 5.3: Generic Event Delivery Using
                                                                                     HTTP Push]
  URI                                                                    obsoleted   [RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1]
  User-Agent                                                             permanent   [RFC9110, Section 10.1.5: HTTP Semantics]
  Variant-Vary                                                           permanent   [RFC 2295: Transparent Content Negotiation in HTTP]
  Vary                                                                   permanent   [RFC9110, Section 12.5.5: HTTP Semantics]
  Via                                                                    permanent   [RFC9110, Section 7.6.3: HTTP Semantics]
  Want-Digest                                                            permanent   [RFC 3230: Instance Digests in HTTP]
  Warning                                                                obsoleted   [RFC9111, Section 5.5: HTTP Caching]
  WWW-Authenticate                                                       permanent   [RFC9110, Section 11.6.1: HTTP Semantics]
  X-Content-Type-Options                                                 permanent   [Fetch]
  X-Frame-Options                                                        permanent   [HTML]
  *                                                                      permanent   [RFC9110, Section 12.5.5: HTTP Semantics]              (reserved)

                                                                 Contact Information

        ID          Name                Contact URI            Last Updated
   [Chet_Ensign] Chet Ensign mailto:chet.ensign&oasis-open.org 2020-09-01
   [OASIS]       OASIS       https://www.oasis-open.org

   Licensing Terms
