Prism is a set of packages for API mocking and contract testing with OpenAPI v2 (formerly known as Swagger) and OpenAPI v3.x.
- Mock Servers: Life-like mock servers from any API Specification Document.
- Validation Proxy: Contract Testing for API Consumers and Developers.
- Comprehensive API Specification Support: OpenAPI 3.0, OpenAPI 2.0 (FKA Swagger) and Postman Collections support.
Note: This branch refers to Prism 3.x, which is the current version most likely you will use. If you're looking for the 2.x version, look at the
Installation and Usage
Prism requires NodeJS >= 12 to properly work.
npm install -g @stoplight/prism-cli # OR yarn global add @stoplight/prism-cli
For more installation options, see our installation documentation.
prism mock https://raw.githack.com/OAI/OpenAPI-Specification/master/examples/v3.0/petstore-expanded.yaml
prism proxy examples/petstore.oas2.yaml https://petstore.swagger.io/v2
Documentation and Community
- Content Negotiation
- Security Validation
- Validation Proxy
- Custom Mocking
- Recording / "Learning" mode to create spec files
- Data Persistence (allow Prism act like a sandbox)
Cannot access mock server when using Docker?
Prism uses localhost by default, which usually means 127.0.0.1. When using docker the mock server will be unreachable outside of the container unless you run the mock command with
Why am I getting 404 errors when I include my basePath?
OpenAPI v2.0 had a concept called "basePath", which was essentially part of the HTTP path the stuff after host name and protocol, and before query string. Unlike the paths in your
paths object, this basePath was applied to every single URL, so Prism v2.x used to do the same. In OpenAPI v3.0 they merged the basePath concept in with the server.url, and Prism v3 has done the same.
We treat OAS2
host + basePath the same as OAS3
server.url, so we do not require them to go in the URL. If you have a base path of
api/v1 and your path is defined as
hello, then a request to
http://localhost:4010/hello would work, but
http://localhost:4010/api/v1/hello will fail. This confuses some, but the other way was confusing to others. Check the default output of Prism CLI to see what URLs you have available.
Is there a hosted version of Prism?
Yes, hosted mocking is available as part of Stoplight Platform. Learn More
- Stoplight Studio: Free visual OpenAPI designer that comes integrated with mocking powered by Prism.
- Stoplight Platform: Collaborative API Design Platform for designing, developing and documenting APIs with hosted mocking powered by Prism.
Help Others Utilize Prism
If you're using Prism for an interesting use case, contact us for a case study. We'll add it to a list here. Spread the goodness
Prism is built on top of lots of excellent packages, and here are a few we'd like to say a special thanks to.
Check these projects out!