Prism – Turn any OpenAPI file into an API server with mocking, transformations, validations, and more.

Prism is an open-source HTTP mock server that can mimic your API’s behavior as if you already built it. Mock HTTP servers are generated from your OpenAPI v2/v3 documents.

Installation per NPM/Yarn

npm install -g @stoplight/prism-cli

# Yarn
yarn global add @stoplight/prism-cli

Once installed, serve your OpenAPI spec as follows:

prism mock petstore.yml

Prism →
Prism (GitHub) →

💡 If you’re using Postman, you can use their built-in Mock Server option