Scalar

Scalar is an open-source API platform founded in 2023 and headquartered in San Francisco, California. The company builds a suite of developer tools centered on the OpenAPI/Swagger specification, including beautiful interactive API references, a modern offline-first API client (a Postman alternative), SDK generators, an MCP and Agent SDK, an API registry, hosted documentation, and a mock server. Scalar's API reference renderer integrates natively with dozens of backend frameworks including FastAPI, NestJS, Hono, Laravel, Spring Boot, and many more, and has been adopted as the default documentation UI by multiple open-source frameworks such as ElysiaJS, Nitro, and Litestar. The GitHub repository has over 15,600 stars and 238 contributors. Scalar is trusted by thousands of development teams and offers free and paid managed hosting with GitHub sync, custom domains, and team collaboration. The company is incorporated as API Documentation, Inc. and is SOC 2 certified and GDPR compliant.