FetchSandbox vs Insomnia
Insomnia and FetchSandbox solve different problems. Insomnia is the client you use to send requests. FetchSandbox is the server you point your client at when you do not want to hit production.
Insomnia is a client, FetchSandbox is a server
Insomnia (Kong Insomnia) is an API client like Postman — request authoring, environments, collections, and now plugins for design and testing. It is the tool you use to send requests, save them, and replay them.
FetchSandbox is what you point Insomnia at when you do not want to hit production. It is a stateful sandbox that responds to your requests with realistic data, persists state, and fires webhook events on state transitions.
A common workflow
- Spin up a FetchSandbox sandbox via the API
- Configure an Insomnia environment with the sandbox base URL and API key
- Send requests from Insomnia to the sandbox — POST, GET, PATCH, DELETE
- The sandbox persists state and fires webhooks — your tests pass or fail like the real API
- Tear down when done — no leftover state in shared dev environments
When you need both
Use Insomnia to author and execute requests. Use FetchSandbox as the target. They complement each other — there is no “pick one” here.
The case where you might pick FetchSandbox over Insomnia's built-in mock features is when you need real lifecycle behavior — POST a customer, then a subscription, then read both back, then verify the webhook arrived. Insomnia mocks are stateless; FetchSandbox is stateful by design.