JSON Meta Application Protocol


The JSON Meta Application Protocol is an Internet protocol for handling the submission and access/synchronization of email, developed as an alternative to IMAP/SMTP and proprietary email APIs that only work with Gmail and 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 and CalDAV, and WebSocket and other support is currently in the works.

Motivation

Developers Bron Gondwana and Neil Jenkins wrote on the Internet Engineering Task Force news site that "the current open protocols connecting email clients and servers, such as IMAP, were not designed for the modern age." They wrote that "IMAP is resource hungry, difficult for developers to learn, and does not work well for network-constrained mobile devices." And they noted that it interfaces in a complicated way with other protocols like SMTP, CalDAV, and CardDAV, and with calendars and contacts.
They believe that IMAP and SMTP are ill-suited to modern mobile networks and in high-latency scenarios, and as a result, this has led to a stagnation in the quality of email clients, and to a proliferation of proprietary protocols for instance for Google's Gmail and Microsoft's Outlook, all of which are meant to mitigate the major drawbacks of using the current generation of popular protocols.

Design

Gondwana and Jenkins wrote, "JMAP is the result of efforts to address shortcomings , 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 JSON. According to Gondwana of Fastmail -- 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 Australia-based email provider Fastmail.
Starting in 2017 a working group at the IETF has been leading the development and standardization process. The documents for the main protocol were completed in July and August of 2019 by Neil Jenkins of Fastmail and Chris Newman of Oracle.
Other ongoing drafts at IETF are for Calendars, Message Disposition Notification, quotas, S/MIME signature verification, and WebSocket.

Implementations