Pay for fixes that hold.
Runs are included.

Do I need to set up any keys or auth?

No. No API keys, no OAuth, no partner onboarding, no signup with the API provider. Pick an API and run it in an isolated sandbox — no real keys, no real charges, no production data touched. It still behaves like the real one, including state changes and webhooks.

What's a run?

One complete integration scenario, not a single API call. Example: Stripe accept_payment — create a customer, attach a card, charge it, then catch the webhook confirming the payment. The sandbox carries state between steps (the customer you just made exists for the charge) and fires the webhooks the real API would. That whole sequence — calls, state, and webhooks end to end — is one run.

Is the free tier actually free?

Yes. 500 runs a month, no card required. Enough to check whether your integration actually works. You'll see the limit in your dashboard — no surprise bills.

Is it open source?

The MCP and CLI are MIT — github.com/fetchsandbox/mcp and github.com/fetchsandbox/cli. You pay for the hosted engine: the sandboxes, the workflows, and the webhook simulation.

Bigger team, SSO, or on-prem?

Email [email protected] and we'll sort it out directly.