JSON Mail Access Protocol

The information below is for an older approved charter
Document Charter JSON Mail Access Protocol WG (jmap) Snapshot
Title JSON Mail Access Protocol
Last updated 2017-03-16
State Approved
WG State Active
IESG Responsible AD Alexey Melnikov
Charter Edit AD Alexey Melnikov
Send notices to (None)


A number of JSON-based email access protocols have been developed that
are proprietary, non-standard, and incompatible with each other. These
protocols are proliferating due to existing standards being insufficient
or poorly suited to the environments they are operating in, particularly
mobile and webmail.

The use of multiple protocols to perform actions within a single
application creates significant support challenges, as users may get a
variety of partial failure modes (for example, can receive email but
cannot send new messages). This is further exacerbated if the different
protocols are authenticated separately.

JMAP specifies the interactions between email clients and mail stores,
providing an alternative to IMAP and SMTP submission. The JMAP working
group will specify a mechanism to allow clients to both view and send
email from a server over a single HTTPS channel with minimal round
trips. A single protocol for receipt and submission will resolve long-
standing difficulties users face setting up clients to talk to servers.

The protocol will support push notification of changes using the
mechanism defined in RFC 8030. This will give mobile clients benefits in
terms of battery life and network usage. It will also support push
notifications via server-sent events
(https://www.w3.org/TR/eventsource/) for direct connection to clients
that can support persistent TCP connections.

Work on JMAP will be bound by the following constraints:

1) The protocol will operate on RFC 5322/MIME (RFC 2045-2047, etc.)
   message objects or information extracted from them.

2) JMAP needs to be implementable on top of an IMAP server, which also
   supports IMAP extensions specified below. The JMAP data model needs
   to remain backwards compatible with the IMAP mailstore model (where a
   message is always associated with a single mailbox), but it might
   support other underlying models (e.g. Gmail-style labels).

   The Working Group will discuss and document how a single server
   or proxy implementation can implement both IMAP and JMAP at the
   same time.

3) "Email submission by placing into designated outbox mailbox" will
   take into consideration extensive IMAPEXT mailing list discussions
   on message submission through IMAP.

4) The work of this group is limited to developing a protocol for a
   client synchronising data with a server. Any server-to-server issues
   are out of scope for this working group.

5) New end-to-end encryption mechanisms are out of scope, but the work
   should consider how to integrate with existing standards such as
   S/MIME and OpenPGP.

6) The working group will coordinate with the Security Area on
   credential management and authentication.

The work will be based on draft-jenkins-jmap and draft-jenkins-jmapmail.
Note that consensus is required both for changes to the current protocol
mechanisms and retention of current mechanisms. In particular, because
something is in the initial document set does not imply that there is
consensus around the feature or around how it is specified. However
gratuitous changes to proposed design should be avoided.

Input to working group discussions shall include:


- Collection Synchronisation for WebDav [RFC 6578]


- IMAP SORT and THREAD Extensions [RFC 5256]

- LEMONADE and experiences from adoption of its output


- SMTP BURL [RFC 4468]

The working group will deliver the following:

- A problem statement detailing the deployment environment and
  situations that motivate work on a new protocol for client to server
  email synchronisation. The working group may choose not to publish
  this as an RFC.

- A document describing an extensible protocol and data structures, with
  support for flood control and batched operations.

- A document describing how to use the extensible protocol over HTTPS
  with the data structures expressed as JSON.

- A document describing a data model for email viewing, management,
  searching, and submission on top of the extensible protocol.

- A document describing how JMAP to IMAP/SUBMIT proxies can be
  implemented. Among different considerations, the document will cover
  security considerations involved in operating such a proxy.

- A document describing how a dual IMAP and JMAP server implementation
  can be done. This can be combined with the above document, if that
  makes sense.

- An executable test suite and documented test cases to assist
  developers of JMAP servers to ensure they conform to the