Scalar

Scalar is an API development platform centred on the OpenAPI standard, providing integrated tooling for documentation, client testing, SDK generation, and API registry management. Its documentation platform renders beautiful, interactive API references from OpenAPI specs and Markdown files, with GitHub synchronisation to keep docs in step with code changes. The API client is a fully open-source, offline-first alternative to Postman for testing and exploring endpoints.

SDK generation automatically produces type-safe client libraries in TypeScript, Python, Go, PHP, Java, and Ruby from an OpenAPI specification. The API registry centralises versioning and management of OpenAPI documents, JSON schemas, and Spectral rulesets with Git integration, providing a single source of truth for API definitions across an organisation.

Scalar is designed for developers and engineering teams who want their API toolchain built on open standards, with consistent documentation, generated SDKs, and a testable client all derived from the same source specification.