Stoplight Prism

What Stoplight Prism is

Stoplight Prism is a free, open-source command-line HTTP server for creating API servers from OpenAPI descriptions and Postman Collections. Teams can generate mock servers to try an API before its backend is built, and Prism can create dynamic, random examples from an API description. It also validates request and response data against that description.

Prism supports OpenAPI 3.1, 3.0, and 2.0, along with Postman Collections. Its proxy mode identifies differences between an OpenAPI document and a target API, which can help teams check API consistency before production. It also supports OpenAPI v3.0 callbacks that deliver payloads to URLs. The maker describes it as useful for parallel frontend and backend development as well as pre-production consistency checks.

The server can run on its own or in continuous integration. Installation options include npm, standalone binaries, Docker, and Docker Compose. The listed Node.js requirement is version 18.20.1 or later, with version 18.16 or later for Node.js 18.x; a standalone binary or Docker image is also available. The repository identifies the license as Apache-2.0. Stoplight also offers hosted mock servers powered by Prism through Stoplight Platform and Stoplight Studio, and points users to its documentation and community for help.

Who it suits

Prism suits developers who need mock APIs while frontend and backend work proceeds in parallel, or who want to validate API requests and responses against a description. It also fits teams checking consistency in pre-production or running API tooling in continuous integration.

Limits

The listed Node.js requirement is version 18.20.1 or later, or version 18.16 or later for Node.js 18.x. A standalone binary and Docker image are also available.

Getting started

1. Install Prism with npm, use a standalone binary, or choose Docker or Docker Compose.
2. If using Node.js, meet the listed version requirement.
3. Provide an OpenAPI description or Postman Collection.
4. Run Prism as a standalone server or in continuous integration.
5. For hosted mock servers, use Stoplight Platform or Stoplight Studio.

Verdict

Choose Prism if you need a free, open-source server for mocking APIs, validating data, or checking a target API against its OpenAPI document. If you want hosted mock servers, Stoplight offers them through its Platform and Studio products.