Give your agents a world to test in.
Stateful simulators for Stripe, GitHub, and more — measured against the real thing.
More than a mock. Safer than a sandbox.
sim
Easy to use while capturing real behavior.
openapi.yaml
POST /charges
GET /charges/:id
POST /refunds
state: balance, disputes…
or: docs · source · traffic
Stateful simulators, built from what you have.
Feed in the spec, the docs, the source code, or captured traffic — out comes a running sim: one static binary, no compose graph. Your service's whole dependency graph collapsed into one process. Every response is measured against the real thing.
Simulators for every service you need.
Payments, source control, infra, AI — the shelf keeps filling.
Stripe
GitHub
Docker
Redis
Shopify
Hugging Face
PostgreSQL
Anthropic
PayPal
Don't see your service? We'll build it.
Any service with a spec can become a sim — internal APIs included.
Request a simulator →