Durable Streams

Durable Streams is an open protocol and reference implementation designed to standardize reliable, resumable, real-time streaming between servers and client applications using simple HTTP semantics, filling a gap left by ephemeral technologies like WebSockets and traditional SSE. It defines an append-only, offset-addressable stream primitive where each stream is mapped to a URL that clients can read from or tail, supporting catch-up reads, historical replay, and live updates with robust resume capabilities across reconnections. The protocol is aimed at modern client-centric applications including AI token streaming, mobile and web UI sync, collaborative editing, and other real-time scenarios where network interruptions are common and clients must maintain continuity.