# stoplightio/prism

Turn any OpenAPI2/3 and Postman Collection file into an API server with mocking, transformations and validations.

Repository: https://github.com/stoplightio/prism
Canonical: https://ross.abutalabs.com/products/stoplightio-prism
Homepage: https://stoplight.io/open-source/prism
Language: TypeScript
License: Apache-2.0
License Family: permissive
Topics: oas, prism, mocking, api-testing, http-proxy, swagger, openapi, mock-server, postman-collection, openapi3, cli, hacktoberfest, stoplight-oss, swagger-oss, stoplight-prism
Last push: 2026-08-26T11:17:50+00:00

## Health v2 (maintenance only)
Score: 97/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 93, longevity 100
- inputs: {"age_days": 3820, "days_push": 7, "days_rel": 47, "gap_med": 0.5, "n_releases_24m": 19}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 5016, forks 412 (observed 2026-08-28T04:09:04.720495+00:00)

## What it is
Prism is an open-source CLI tool that turns OpenAPI v2/v3 documents or Postman Collections into a fully functional HTTP mock server with dynamic example generation, request/response validation, and a contract-testing validation proxy. It runs from the command line via Node.js and can be used standalone or in CI pipelines.

## Use cases
- spin up a mock server from an OpenAPI spec
- let frontend teams develop before the backend exists
- validate API responses against an OpenAPI contract
- run contract testing in CI with a validation proxy
- generate dynamic random examples from an API description
- mock OpenAPI callbacks for webhook payloads

## When to choose
- you have an OpenAPI or Postman Collection spec and need a realistic mock API quickly
- you want to check that an implemented API matches its specification
- you prefer a lightweight CLI over a hosted mocking service
- you need request and response validation during API development

## When to avoid
- you need stateful mocking with persistent data across requests
- your API is not described by OpenAPI or Postman Collections
- you need a GUI-based mock management experience
- you require gRPC or GraphQL mocking

## Facets
- artifact type: cli-tool
- maturity: active
- function: mocking, http-server, testing, api-framework, cli
- domain: apis, developer-tools, testing, web-development
- platform: cli, cross-platform
- tags: openapi, swagger, postman-collection, mock-server, contract-testing, validation-proxy, api-mocking, nodejs

## Member repositories
- stoplightio/prism (main) score 97

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:04.720495+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:17:31.888465+00:00, confidence not recorded.
  - readme: https://github.com/stoplightio/prism (fetched 2026-08-28T04:09:04.720495+00:00, sha 4d0fab278b88)
  - homepage: https://stoplight.io/open-source/prism (fetched 2026-08-29T08:58:44.369759+00:00, sha e8c043a3f902)
  - site_page: https://docs.stoplight.io/ (fetched 2026-08-29T08:58:44.378990+00:00, sha a30be4a84572)
  - site_page: https://stoplight.io/about (fetched 2026-08-29T08:58:44.383255+00:00, sha 2ed9f2f75d44)
  - site_page: https://stoplight.io/pricing (fetched 2026-08-29T08:58:44.380751+00:00, sha 070c1e91d9e8)
- Data as of 2026-08-30T08:39:29.467469+00:00.