Rivet launches an open-source actor platform for agents, using S3-backed storage

Rivet says its lightweight actors can replace resource-heavy per-agent sandboxes, with a 72 KB baseline and 4.9 ms p99 startup versus 512 MB and 1.7 seconds for minimal sandboxes. Its storage design acknowledges writes after SSD replication across two of three availability zones, then batches them to S3; the company reports 1.07 ms p99 durable writes and storage 10× cheaper than EBS gp3. Rivet is available as a self-hosted Rust binary or through cloud and VPC deployment options, and actors support TypeScript and Rust.

The SSD-first write path lets teams keep latency low while moving large, infrequently accessed agent data to cheaper S3 storage; the trade-off is slower cache-miss reads, reported at 138 ms p99. Builders should validate cache sizing and workload-specific read patterns before choosing this design, since the article does not provide independent benchmarks or detailed test conditions.