



Internet Engineering Task Force (IETF)                       R. Stepanek
Request for Comments: 9982                                      Fastmail
Updates: 9555                                                   May 2026
Category: Standards Track                                               
ISSN: 2070-1721


      JSContact Version 2.0: A JSON Representation of Contact Data

Abstract

   This document defines version "2.0" of JSContact.  It defines the uid
   property of a Card object to be optional, rather than mandatory, as
   defined previously in version "1.0".  All other definitions of
   JSContact version "1.0" remain as defined in RFC 9553.  This document
   updates RFC 9555 by redefining how to convert the now optional uid
   property from and to vCard.  It also registers the vCard JSCOMPS
   parameter at IANA, which was defined but not registered in RFC 9555.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc9982.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   Trust Legal Provisions and are provided without warranty as described
   in the Revised BSD License.

Table of Contents

   1.  Introduction
   2.  Notational Conventions
   3.  JSContact Version 2.0
   4.  Redefined uid Property
   5.  Redefined Conversion Rule for the uid Property
   6.  Other Changes
   7.  IANA Considerations
     7.1.  Update to the JSContact Version Registry
     7.2.  Update to the JSContact Properties Registry
     7.3.  Update to the vCard Parameters Registry
   8.  Security Considerations
   9.  References
     9.1.  Normative References
     9.2.  Informative References
   Author's Address

1.  Introduction

   JSContact [RFC9553] defines the Card object uid property, a mandatory
   property that contains a unique identifier for the entity represented
   by that contact card.  For the same purpose, the vCard [RFC6350]
   contact format defines the UID property, an optional property of a
   vCard instance.  Throughout the rest of this document, the term uid
   (all lowercase) denotes the JSContact uid property, and the term UID
   (all uppercase) denotes the vCard UID property.

   The uid property being defined as mandatory in JSContact has shown to
   be applicable for some use cases but turned out to be an issue in
   other contexts.

   1.  A stated goal of JSContact is to be compatible with the semantics
       of the vCard data format (Section 1 of [RFC9553]).  But [RFC6350]
       defines the UID property of a vCard to be optional, and
       consequently, the semantics of JSContact and vCard differ for
       such a crucial common element.

   2.  Address book synchronization protocols, such as CardDAV [RFC6352]
       and JMAP for Contacts [RFC9610], require the uid property.  But
       other protocols, such as RDAP [RFC9083], have no use for it.
       JSContact should not require protocols to generate unique
       identifiers when they are irrelevant or even detrimental to the
       use case.

   3.  Converting vCards having no UID property to JSContact is
       especially problematic: Section 2.1.1 of [RFC9555] requires
       implementations in this case to generate a unique identifier
       during conversion but does not require it to be the same across
       implementations or even one implementation converting the same
       Card multiple times.  A recipient being unaware that the uid
       property value of such a Card object is ephemeral might refer to
       it in the members property or relatedTo property of another Card
       object, introducing invalid relations between contact cards.

2.  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.

   The ABNF definitions in this document use the notations of [RFC5234].
   ABNF rules not defined in this document are defined in either
   [RFC5234] (such as the ABNF for CRLF, WSP, DQUOTE, VCHAR, ALPHA, and
   DIGIT) or [RFC6350].

3.  JSContact Version 2.0

   This document redefines the uid property of a Card object to become
   optional.  Other than that, the property definition is left
   unchanged.  This change requires the major version of JSContact to
   change, so this document defines the JSContact version to become
   "2.0".  For further information about versioning JSContact data, see
   Section 1.9 of [RFC9553].

   Implementations MUST create JSContact data that complies with the
   definitions of version "2.0" (or some later registered version) and
   MUST set the version property of the JSContact Card object to that
   version.  They MUST NOT reject a Card object without the uid property
   as invalid unless specified differently in another document or unless
   the Card version property has value "1.0".  As any valid version
   "1.0" JSContact Card is also valid according to version "2.0", there
   is no need to migrate existing JSContact data.

   This document does not redefine the vCard UID property.

4.  Redefined uid Property

   This document redefines the type signature of the uid property,
   originally defined in Section 2.1.9 of [RFC9553].

   OLD:

   |  *uid: String (mandatory).*

   NEW:

   |  *uid: String (optional).*

   The remaining property definition is left unchanged, with the
   following additional paragraph:

   |  A Card without an uid property cannot be referred to as a group
   |  member in the members property (Section 2.1.6 of [RFC9553]) or put
   |  in relation to another Card object in the relatedTo property
   |  (Section 2.1.8 of [RFC9553]).

5.  Redefined Conversion Rule for the uid Property

   This document redefines how to convert the Card uid property from
   vCard, originally defined in Section 2.1.1 of [RFC9555].  The new
   conversion rule is as follows:

   Implementations that convert a vCard without a UID property
   (Section 6.7.6 of [RFC6350]) to a Card of version "2.0" or higher
   MUST NOT generate a unique identifier as a value for the uid property
   (Section 2.1.9 of [RFC9553]).

   When converting a vCard without a UID property to JSContact version
   "1.0", implementations MUST generate a value for the uid property.
   How to generate unique identifiers is implementation-specific.
   Implementations SHOULD generate the same value when generating the
   same Card multiple times, but as Section 1 describes, this still
   cannot prevent interoperability issues.  Consequently,
   implementations SHOULD NOT convert to version "1.0" Card objects.

6.  Other Changes

   This document also registers the JSCOMPS parameter in the IANA "vCard
   Parameters" registry.  The parameter was defined in Section 3.3.1 of
   [RFC9555] but mistakenly not registered at IANA.

7.  IANA Considerations

7.1.  Update to the JSContact Version Registry

   IANA has updated the "JSContact Version" registry, originally created
   in Section 3.4 of [RFC9553], by adding the following record:

           +===============+=======================+===========+
           | Major Version | Highest Minor Version | Reference |
           +===============+=======================+===========+
           | 2             | 0                     | RFC 9982  |
           +---------------+-----------------------+-----------+

                    Table 1: JSContact Version Registry

7.2.  Update to the JSContact Properties Registry

   IANA has updated the "JSContact Properties" registry, originally
   created in Section 3.5 of [RFC9553]: In the "Reference/Description"
   column of the uid property, a reference to Section 4 of this document
   has been added.

7.3.  Update to the vCard Parameters Registry

   IANA has updated the "vCard Parameters" registry within the "vCard
   Elements" registry group by adding the following entry:

          +===========+===========+============================+
          | Namespace | Parameter | Reference                  |
          +===========+===========+============================+
          |           | JSCOMPS   | Section 3.3.1 of [RFC9555] |
          +-----------+-----------+----------------------------+

                    Table 2: vCard Parameters Registry

8.  Security Considerations

   This document does not provide new security considerations.  The
   security considerations of Section 4 of [RFC9553] apply.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [RFC6350]  Perreault, S., "vCard Format Specification", RFC 6350,
              DOI 10.17487/RFC6350, August 2011,
              <https://www.rfc-editor.org/info/rfc6350>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC9553]  Stepanek, R. and M. Loffredo, "JSContact: A JSON
              Representation of Contact Data", RFC 9553,
              DOI 10.17487/RFC9553, May 2024,
              <https://www.rfc-editor.org/info/rfc9553>.

   [RFC9555]  Loffredo, M. and R. Stepanek, "JSContact: Converting from
              and to vCard", RFC 9555, DOI 10.17487/RFC9555, May 2024,
              <https://www.rfc-editor.org/info/rfc9555>.

9.2.  Informative References

   [RFC6352]  Daboo, C., "CardDAV: vCard Extensions to Web Distributed
              Authoring and Versioning (WebDAV)", RFC 6352,
              DOI 10.17487/RFC6352, August 2011,
              <https://www.rfc-editor.org/info/rfc6352>.

   [RFC9083]  Hollenbeck, S. and A. Newton, "JSON Responses for the
              Registration Data Access Protocol (RDAP)", STD 95,
              RFC 9083, DOI 10.17487/RFC9083, June 2021,
              <https://www.rfc-editor.org/info/rfc9083>.

   [RFC9610]  Jenkins, N., Ed., "JSON Meta Application Protocol (JMAP)
              for Contacts", RFC 9610, DOI 10.17487/RFC9610, December
              2024, <https://www.rfc-editor.org/info/rfc9610>.

Author's Address

   Robert Stepanek
   Fastmail
   PO Box 234
   Collins St. West
   Melbourne VIC 8007
   Australia
   Email: rsto@fastmailteam.com
