Celeriant

An append-only event store for the write side of CQRS. Distributed, strictly ordered, built in Rust.

Celeriant enforces business invariants at write time across many streams: optimistic concurrency, idempotent retries, per-aggregate ordering, and cluster-wide durability. 325,000 durable writes a second across 36,000 connections, p99 201 ms end-to-end over mTLS, every write fsync'd on both nodes before the ack. See Performance.

Start here

• Quickstart: run a node and append your first event in five minutes.
• What is Celeriant: the problem it solves, and how.
• When not to use it: read this before you adopt anything.
• Concepts: the model: aggregates, ordering, concurrency, watch.

Pre-release

Celeriant is pre-1.0. The wire format can still change between releases, and the open-source binaries ship with the Apache-2.0 release. If you need stability today, see when not to use it.