Rivet.dev

Rivet.dev is a coding tool. Rivet is an open-source, self-hostable orchestrator that runs agents, workflows and sandboxes as durable Actors with built-in SQLite and filesystem storage, fast cold starts, and deployment options from local to managed cloud and BYOC.

Rivet is an open-source orchestrator built for the workloads that AI agents generate and depend on. Its central idea is the Actor: a small, durable process that carries its own state and can stand in for an agent, a multi-step workflow, a sandbox for untrusted code, or a per-user backend. Each Actor receives a SQLite database and a POSIX filesystem, with storage tiered to S3, so state survives restarts and idle instances cost nothing while parked. The target audience is engineering teams building agent products: coding agents, agent-driven app builders, company-specific agents running inside a private cloud, personal assistants, and realtime collaborative apps. Actors live inside worker processes a team already operates rather than in separate containers or VMs, which is how the site justifies its density claims of roughly 72 KB per running Actor and cold starts around 12 ms, measured on FoundationDB with the Rust SDK. An experimental feature is involved in the cold-start figure. In practice, a developer installs the rivetkit package, defines Actors in TypeScript, and connects to a control plane that handles scheduling, routing and observability. Typed client SDKs, React hooks, HTTP and WebSocket addressing, actor-to-actor calls, cron scheduling and OpenTelemetry output come built in. Workers run on plain Node.js or Bun rather than a custom runtime, and Rust is supported too. The same binary and APIs run on a laptop and in production. Deployment is flexible. The Apache 2.0 control plane ships as a single Rust binary that can be self-hosted on Kubernetes, Docker Compose, virtual machines or platforms such as Railway and Render, backed by Postgres or FoundationDB. Rivet Cloud offers a managed option, and a bring-your-own-cloud mode has Rivet operate the control plane inside a customer VPC, including air-gapped setups. Among alternatives, Rivet positions itself against Kubernetes for stateful workloads and as a self-hostable answer to Cloudflare Durable Objects, citing the lack of memory and SQLite size caps. Teams wanting a simple hosted function runner will find it more infrastructure-oriented than that.