Discord has open-sourced Osprey, an internal safety rules engine capable of evaluating 2.3 million rules per second across 400 million daily actions. The system uses a polyglot architecture: a Rust coordinator handles high-concurrency traffic and gRPC routing, while stateless Python worker nodes execute rules written in SML, a Python-based domain-specific language. Rules are parsed into an AST at startup to minimize per-event overhead and distributed via ETCD for live updates without redeployment. Output sinks are pluggable via the Pluggy library, with a reference deployment using Apache Kafka and Apache Druid. The project is managed under the ROOST organization and has seen early adoption by Bluesky and Matrix.org.
Sort: