Internet-Draft OAuth Tokens in HTTP Header November 2025
Chalk Expires 19 May 2026 [Page]
Workgroup:
Web Authorization Protocol
Internet-Draft:
draft-chalk-oauth-tokens-in-header-latest
Published:
Intended Status:
Standards Track
Expires:
Author:
O. Chalk
Government Digital Service, UK

OAuth Tokens in HTTP Header

Abstract

This specification extends OAuth 2.0 [RFC6749] by defining a mechanism for resource servers or authorisation servers to convey inline token updates and related metadata to clients using the Authentication-Info HTTP header.

About This Document

This note is to be removed before publishing as an RFC.

The latest revision of this draft can be found at https://OllieJC.github.io/draft-chalk-oauth-tokens-in-header/draft-chalk-oauth-tokens-in-header.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-chalk-oauth-tokens-in-header/.

Discussion of this document takes place on the Web Authorization Protocol Working Group mailing list (mailto:oauth@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/oauth/. Subscribe at https://www.ietf.org/mailman/listinfo/oauth/.

Source for this draft and an issue tracker can be found at https://github.com/OllieJC/draft-chalk-oauth-tokens-in-header.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 19 May 2026.

Table of Contents

1. Introduction

OAuth deployments range from simple bearer‑only configurations to complex ecosystems with distinct authorisation and resource servers. In some scenarios a resource server holds enough contextual information to advise the client of a refreshed or more suitable token for future use. Existing OAuth flows, however, obligate the client to perform a separate interaction with the authorisation server to obtain such updates, and certain deployments may lack an authorisation server altogether.

This document defines a lightweight mechanism that leverages the Authentication‑Info header (originally specified in [RFC7615] and incorporated into [RFC9110]) to convey inline token updates and associated metadata within a normal HTTP response. The header can be processed transparently by HTTP implementations, potentially even at a proxy or edge service, and does not alter the client's request semantics. Recipients treat the conveyed values as hints - they may adopt the suggested token but are not required to do so - thereby preserving compatibility with existing OAuth behaviour while offering an optional optimisation for efficiency and flexibility.

2. Conventions and Definitions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. Security Considerations

TODO Security

4. IANA Considerations

This document has no IANA actions.

5. Normative References

[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC6749]
Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, , <https://www.rfc-editor.org/rfc/rfc6749>.
[RFC7615]
Reschke, J., "HTTP Authentication-Info and Proxy-Authentication-Info Response Header Fields", RFC 7615, DOI 10.17487/RFC7615, , <https://www.rfc-editor.org/rfc/rfc7615>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC9110]
Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP Semantics", STD 97, RFC 9110, DOI 10.17487/RFC9110, , <https://www.rfc-editor.org/rfc/rfc9110>.

Acknowledgments

TODO acknowledge.

Author's Address

Ollie Chalk
Government Digital Service, UK