# openmls/openmls

Rust implementation of the Messaging Layer Security (MLS) protocol

Repository: https://github.com/openmls/openmls
Canonical: https://ross.abutalabs.com/products/openmls
Homepage: https://openmls.tech
Language: Rust
License: MIT
License Family: permissive
Topics: rust, mls, security, openmls
Last push: 2026-09-02T19:17:34+00:00

## Health v2 (maintenance only)
Score: 95/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 100, release rhythm 87, longevity 100
- inputs: {"age_days": 2300, "days_push": 0, "days_rel": 8, "gap_med": 41.5, "n_releases_24m": 9}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1022, forks 175 (observed 2026-09-03T02:15:15.823250+00:00)

## What it is
OpenMLS is a Rust implementation of the Messaging Layer Security (MLS) protocol as specified in RFC 9420. It is a library providing safe, easy-to-use end-to-end encryption for group messaging, with pluggable cryptographic backends and support for targets including Linux, Windows, macOS, Android, iOS, and WebAssembly.

## Use cases
- add end-to-end encrypted group messaging to an app
- implement the MLS protocol (RFC 9420) in Rust
- encrypt messages for groups of two to many participants
- build a secure messaging library with pluggable crypto backends
- compile E2EE messaging code to WebAssembly or mobile platforms
- resolve group state forks in MLS-based messaging

## When to choose
- you need a standards-compliant MLS (RFC 9420) implementation
- you want safe, memory-safe Rust code for E2EE group messaging
- you need cross-platform support including mobile and WASM
- you want to bring your own cryptographic provider via traits

## When to avoid
- you need a complete messaging application rather than a protocol library
- you need a non-Rust language implementation without FFI/wasm compilation
- you require cryptographic primitives implemented in the library itself (it delegates to external providers)

## Facets
- artifact type: library
- maturity: active
- function: cryptography, security, sdk
- domain: security, privacy
- platform: windows, wasm, rust, cross-platform
- tags: mls, rfc9420, e2ee, end-to-end-encryption, group-messaging, ietf, messaging-layer-security, messaging, linux, macos, android, ios

## Member repositories
- openmls/openmls (main) score 95

## Provenance
- Observed fields: from GitHub, fetched 2026-09-03T02:15:15.823250+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:11:20.274642+00:00, confidence not recorded.
  - readme: https://github.com/openmls/openmls (fetched 2026-09-03T02:15:15.823250+00:00, sha 437e5f707023)
  - homepage: https://openmls.tech (fetched 2026-08-29T13:10:21.387008+00:00, sha e9cc78791c5f)
  - registry_crates: https://crates.io/api/v1/crates/openmls (fetched 2026-08-29T13:10:21.396026+00:00, sha b764d4ef43c9)
- Data as of 2026-08-30T08:39:29.467469+00:00.