Carbon

Carbon turns an API description — OpenAPI, AsyncAPI, GraphQL, protobuf, gRPC, HAR, or a Postman collection — into a deterministic, stateful runtime you can hit locally, snapshot, rewind, and share.

Three ideas that make Carbon different

• Spec ingest. Any supported format normalizes into one Intermediate Representation, then compiles into a behavior graph. One runtime serves them all — see Spec to runtime.
• Stateful runtime. POST /users creates a resource that later GET /users/:id calls return. Relationships between endpoints are inferred, so the replica behaves like the real service, not a static fixture. See State engine.
• Snapshots + rewind. Serialize the runtime’s entire state, commit it, and restore in one call. Every CI run starts from the same baseline.

Get moving

Quickstart Boot your first replica in five minutes.

CLI reference Every command, every flag, with an example.

Deployment Fly.io, self-hosted, and Prometheus alerts.

Enterprise SSO, SCIM, compliance exports, plan matrix.