The JSON Meta Application Protocol (JMAP) is a set of related open

Internet Standard In computer network engineering, an Internet Standard is a normative specification of a technology or methodology applicable to the Internet. Internet Standards are created and published by the Internet Engineering Task Force (IETF). They allow ...

protocol Protocol may refer to: Sociology and politics * Protocol (politics) Protocol originally (in Late Middle English, c. 15th century) meant the minutes or logbook taken at a meeting, upon which an agreement was based. The term now commonly refers to ...

s for handling

email Electronic mail (usually shortened to email; alternatively hyphenated e-mail) is a method of transmitting and receiving Digital media, digital messages using electronics, electronic devices over a computer network. It was conceived in the ...

. JMAP is implemented using

JSON JSON (JavaScript Object Notation, pronounced or ) is an open standard file format and electronic data interchange, data interchange format that uses Human-readable medium and data, human-readable text to store and transmit data objects consi ...

API An application programming interface (API) is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build ...

s over

HTTP HTTP (Hypertext Transfer Protocol) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, wher ...

and has been developed as an alternative to

IMAP In computing, the Internet Message Access Protocol (IMAP) is an Internet standard protocol used by email clients to retrieve email messages from a mail server over a TCP/IP connection. IMAP is defined by . IMAP was designed with the goal of per ...

and proprietary email APIs such as Google's Gmail and Microsoft's

MAPI Messaging Application Programming Interface (MAPI) is an Application programming interface, API for Microsoft Windows which allows programs to become email-aware. While MAPI is designed to be independent of the protocol, it is usually used to com ...

(used by Outlook). Additional protocols and data models being built on top of the core of JMAP for handling contacts and calendar synchronization are meant to be potential replacements for

CardDAV vCard Extensions to WebDAV (CardDAV) is an address book client/server protocol designed to allow users to access and share contact data on a server. The CardDAV protocol was developed by the IETF and was published as in August 2011. CardDAV is ...

and

CalDAV Calendaring Extensions to WebDAV, or CalDAV, is an Internet standard allowing a client to access and manage calendar data along with the ability to schedule meetings with users on the same or on remote servers. It lets multiple users in differe ...

, and other support is currently in the works.

Motivation

Developers Bron Gondwana and Neil Jenkins wrote on the

Internet Engineering Task Force The Internet Engineering Task Force (IETF) is a standards organization for the Internet standard, Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster ...

(IETF) news site that "the current open protocols connecting email clients and servers, such as IMAP, were not designed for the modern age." They cited IMAP's complexity, high resource use, poor adaptability to the network constraints of modern mobile devices, and complex interactions with other protocols like SMTP, CalDAV, and CardDAV. They believe this has resulted in a stagnation in the quality of (especially free) email clients, and the creation of proprietary protocols to overcome these limitations, for instance

, used by

Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...

's Exchange Server and

Outlook Outlook or The Outlook may refer to: Computing * Microsoft Outlook, also referred to as ''the classic Outlook'' an e-mail client and personal information management software product from Microsoft * Outlook for Windows, also referred to as ''the ...

email products.

Design

Gondwana and Jenkins wrote, "JMAP is the result of efforts to address shortcomings n existing protocols providing a modern, efficient, easy-to-use API, built on many years of experience and field testing." The protocol was developed with the intention of providing a modern open, reliable, and easy-to-use solution, and as a result it relies heavily upon the commonly-implemented

(JavaScript Object Notation). According to Gondwana of

Fastmail Fastmail is an Email hosting service, email hosting company based in Melbourne, Victoria, Melbourne, Australia. In addition to its Fastmail-branded services, the company also operates Topicbox, a Electronic mailing list, mailing list service, and ...

, which has been a leading developer of the protocol, "The use of JSON and HTTP as the basis of JMAP was always a key point — it means that people wanting to build something on top of email don’t have to re-implement complex parsers or find a software library in order to get started." After atmail decided to implement JMAP, CEO Dave Richards wrote in 2018 that "the complexities required to implement IMAP in both user and server side software has resulted in user difficulties and a lack of software options, along with a rigid user experience... The new JMAP protocol solves the existing issues and is modular enough to take advantage of future technology. JMAP makes email better."

Development

JMAP started around 2014 as an internal development project by the Australian-based email provider

. Starting in 2017 a working group at the

IETF The Internet Engineering Task Force (IETF) is a standards organization for the Internet standard, Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster ...

has been leading the development and standardization process. The core protocol and mail specifications were published in July and August 2019 by Neil Jenkins of Fastmail and Chris Newman of Oracle, as and . The WebSocket specification was later published in August 2020 as , and Message Disposition Notification (

return receipt In email, a return receipt is an acknowledgment by the recipient's email client to the sender of receipt of an email message. What acknowledgment, if any, is sent by the recipient to the sender is dependent on the email software of the recipient. ...

s) in March 2021 as . Several further JMAP extensions have been published as proposed standards: blob management (), Quotas (), Contacts (), Sharing (),

Sieve A sieve (), fine mesh strainer, or sift is a tool used for separating wanted elements from unwanted material or for controlling the particle size distribution of a sample, using a screen such as a woven mesh or net or perforated sheet m ...

mail filtering (), and using VAPID with Web Push (). Other ongoing JMAP drafts at IETF are for dealing with calendars, tasks, implementation profiles, and file storage. The working group originally set milestones for some of these to be finalised by the end of 2020.

Implementations

Servers: * Since its release of version 3.6.0 in 2021,

Apache Software Foundation The Apache Software Foundation ( ; ASF) is an American nonprofit corporation (classified as a 501(c)(3) organization in the United States) to support a number of open-source software projects. The ASF was formed from a group of developers of the ...

’s free mail-server

Apache James Apache James, or Java Apache Mail Enterprise Server, is an open source SMTP and POP3 mail transfer agent written entirely in Java. James is maintained by contributors to the Apache Software Foundation, with initial contributions by Serge K ...

has included support for the JMAP RFCs. The OpenPaas collaboration platform implements its email and webmail UI using James and JMAP. * Cyrus IMAP provisionally supports the JMAP protocol standards as of version 3.8.3, released in May 2024, when built with this functionality. * Stalwart Mail Server is a scalable open-source mail server written in Rust with full support for JMAP Core, JMAP Mail, JMAP over WebSocket at IMAP4rev2. Clients: * Mailtemi is a JMAP/MS Graph/IMAP email app for iOS and Android. It supports multiple email accounts, contacts, and calendars. * Ltt.rs is a proof of concept email client for Android that supports only JMAP. * Twake Mail is an open source app client for iOS and Android developed by Linagora.

References

{{Email clients Internet mail protocols JSON

Motivation

Design

Development

Implementations

See also

References