Firefly overview

Firefly is Lupyd’s end-to-end encrypted messaging stack. It provides:

• 1:1 messaging using the Signal protocol (libsignal) with prekey bundles.
• Group messaging using Messaging Layer Security (MLS, RFC 9420) with Lupyd-specific roles, channels, and permissions.
• Multi-device support — up to five devices per user, each with its own keys.
• Real-time delivery over WebSocket or WebTransport (HTTP/3).
• Voice/video calls and group meetings, encrypted backups, pinned messages, and shareable group history.

Components

Repository	Contents
firefly	Client libraries and the protocol schema: firefly-protos (protobuf), firefly-core (MLS identity, rules, extensions), firefly-client (high-level async Rust client), and firefly-client-node / firefly-client-js (WebAssembly + TypeScript bindings).
firefly-mls	The Firefly server (firefly-server): HTTP API, WebSocket and WebTransport endpoints, PostgreSQL storage.

Tip

Most applications should use the client SDK, which implements key management, MLS, Signal sessions, and the real-time protocol. Use the raw HTTP API only if you are building a new client library.

At a glance

Protocols	HTTP/1.1, HTTP/2, WebSocket, WebTransport (HTTP/3 over QUIC)
Encoding	Protobuf, package firefly (crates/protos/protobufs/message.proto)
Authentication	Auth0 Bearer JWT, plus a Firefly-signed device credential
MLS ciphersuite	P256_AES128 (MLS_128_DHKEMP256_AES128GCM_SHA256_P256)
Default port	39205 (TCP for HTTP/WebSocket; UDP for WebTransport)
Request timeout	30 seconds by default

Authentication and devicesTokens, device registration, and signed credentials.

Real-time connectionWebSocket and WebTransport framing, sync, and keepalive.

End-to-end encryptionMLS groups, Signal sessions, roles, and permissions.

HTTP API referenceEvery REST endpoint.

Client SDKRust and JavaScript libraries.

Self-hostingRun and configure the Firefly server.