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The API for better email

JMAP is the open protocol that replaces IMAP (and CardDAV and CalDAV). It’s faster, simpler, more powerful, and built for how email works today.

Why JMAP? Explore the spec Find apps and libraries
Real-time push

Instant updates.
Zero overhead.

Get instant push via EventSource — one connection, all mailboxes. Or use WebPush for mobile-compatible push, no permanent connection required.
JMAP push
<1s IMAP polling
30s+
Mobile battery life

Efficiency that
matters.

2–3× less power usage than IMAP, measured on real devices.
JMAP
IMAP
Performance

Rock solid sync.
Every time.

Sync changes more easily, more efficiently, and much, much faster. A single HTTP roundtrip is often all that's required.
JMAP
13.1 KB
T’bird
2.9 MB
Bandwidth used when resyncing after restart on a mailbox with 28,234 messages.
Standard HTTP + JSON

Deployment
made easy.

JMAP works natively with existing infrastructure like nginx, Cloudflare, WAFs, load balancers, and DDoS protection — no specialist IMAP tooling required. And it works just as great for webmail as native clients.
JMAP for Mail
JMAP Core
JSON
HTTP / TLS
POST /jmap/api
connected
RFC

An open IETF standard.

No patents. No fees. Fully documented. JMAP is an open standard any organisation can implement, not more proprietary lock-in from big tech companies.

Read the spec
Spec complexity

So. Much.
Simpler.

5× smaller than IMAP
51k vs 272k words
JMAP
51k
IMAP
272k
Running code

A fast-growing
ecosystem.

Webmail Rust library iOS app Server Typescript library Terminal client
Find implementations
Get started

Up and running in minutes

  1. Discover the endpoint

    Fetch /.well-known/jmap for the session object - capabilities, accounts, and all API URLs.

  2. Authenticate

    Standard OAuth 2.0 or Bearer tokens. No custom auth protocol to implement. Works with what you already have.

  3. Make your first call

    POST a methodCalls array. Query, fetch, and send, all in one HTTP request.

  4. Subscribe to push

    Open an EventSource connection. Your UI stays current without polling. All mailboxes, instantly.

Explore

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