| RFC 9982 | JSContact Version 2.0 | May 2026 |
| Stepanek | Standards Track | [Page] |
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.¶
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 (c) 2026 IETF Trust and the persons identified as the document authors. All rights reserved.¶
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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.¶
For example, the CardDAV protocol [RFC6352] requires the UID property of a vCard object [RFC6350] to be set. Accordingly, an internet server that implements both CardDAV and JSON Meta Application Protocol (JMAP) for Contacts [RFC9610] requires the uid property of a JSContact Card to be set. In contrast, protocols such as Registration Data Access Protocol (RDAP) [RFC9083] have no use for the uid property, either because they use different identifiers or they prefer to not include any unique identifier in the contact data at all. JSContact should not require them to generate unique identifiers that are irrelevant to their use case.¶
Also, one of the stated goals 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.¶
In case of vCards without a UID property (Section 6.7.6 of [RFC6350]) being converted to JSContact, requiring unique identifiers is especially problematic: The Card uid property is mandatory, and accordingly, Section 2.1.1 of [RFC9555] requires implementations to generate some unique identifier for it during conversion, but it does not guarantee 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.¶
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].¶
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.¶
Setting the uid property is use case specific. If an implementation is able to consistently generate the exact same unique identifier for a JSContact Card representing the same entity and no protocol-specific concerns prevail, it is recommended to set the uid property.¶
This document does not redefine the vCard 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]).¶
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. Generating unique identifiers is implementation specific. An implementation SHOULD generate the same value when generating the same Card multiple times. Section 1 describes why this is problematic. Consequently, implementations SHOULD NOT convert to version "1.0" Card objects.¶
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.¶
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 |
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.¶
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] |
This document does not provide new security considerations. The security considerations of Section 4 of [RFC9553] apply.¶