Turn an OpenAPI document into a mock server that validates as well as responds.
Prism, from Stoplight, reads an OpenAPI description and serves a mock API from it, generating responses that conform to the schema and validating incoming requests against it. Because the spec is the only input, the mock cannot drift from the contract.
Best for
Free and open source
Open sourceFree tier: Everything, self-hosted
What drives the bill: Free and open source. You pay in engineering time and CI minutes.
Check current pricing on Stoplight (SmartBear)’s siteFigures are indicative and were last reviewed August 2026. Vendors change pricing often; confirm before you commit.
No reviews of Prism yet. If you have used it in anger, yours would be the first.
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