Internet-Draft Link-Template March 2024
Nottingham Expires 30 September 2024 [Page]
Building Blocks for HTTP APIs
Intended Status:
Standards Track
M. Nottingham

The Link-Template HTTP Header Field


This specification defines the Link-Template HTTP header field, providing a means for describing the structure of a link between two resources, so that new links can be generated.

About This Document

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

The latest revision of this draft can be found at Status information for this document may be found at

Discussion of this document takes place on the Building Blocks for HTTP APIs Working Group mailing list (, which is archived at Subscribe at

Source for this draft and an issue tracker can be found at

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

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 30 September 2024.

Table of Contents

1. Introduction

[URI-TEMPLATE] defines a syntax for templates that, when expanded using a set of variables, results in a URI [URI].

This specification defines a HTTP header field [HTTP] for conveying templates for links in the headers of a HTTP message. It is complimentary to the Link header field defined in Section 3 of [WEB-LINKING], which carries links directly.

1.1. Notational Conventions

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.

This specification uses the following terms from [STRUCTURED-FIELDS]: List, String, Display String, Parameter.

3. Security Considerations

The security consideration for the Link header field in [WEB-LINKING] and those for URI Templates [URI-TEMPLATE] both apply.

Target attributes that are conveyed via Display Strings can be vulnerable to a wide variety of attacks. See [UNICODE-SECURITY] for advice regarding their handling. Specific advice is not given by this specification, since there are a variety of potential use cases for such attributes.

4. IANA Considerations

This specification enters the "Link-Template" into the Hypertext Transfer Protocol (HTTP) Field Name Registry.

5. Normative References

Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP Semantics", STD 97, RFC 9110, DOI 10.17487/RFC9110, , <>.
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <>.
Nottingham, M. and P. Kamp, "Structured Field Values for HTTP", Work in Progress, Internet-Draft, draft-ietf-httpbis-sfbis-05, , <>.
Davis, M. and M. Suignard, "Unicode Security Considerations", Unicode Technical Report #16, , <>.
Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, , <>.
Gregorio, J., Fielding, R., Hadley, M., Nottingham, M., and D. Orchard, "URI Template", RFC 6570, DOI 10.17487/RFC6570, , <>.
Nottingham, M., "Web Linking", RFC 8288, DOI 10.17487/RFC8288, , <>.

Author's Address

Mark Nottingham