What is Scalar used for?

Scalar is an open-source API platform that renders interactive OpenAPI and Swagger references and includes an offline-first API client with desktop apps. It is a good fit for publishing developer-friendly API documentation, testing APIs from an OpenAPI spec and replacing Swagger UI with a modern reference.

Is Scalar open source?

Yes. Scalar is open source under the MIT licence. Its source code is on GitHub at scalar/scalar and is written mainly in TypeScript.

Yes. Scalar is open source, so the software itself is free to use. Paid plans are also available, starting at $150 per month.

What is Scalar an alternative to?

Scalar is an open-source alternative to Postman, ReadMe, Stoplight and Redocly. Other open-source alternatives to Postman include Voiden, Insomnia and Mockoon.

Is Scalar actively maintained?

Yes. The most recent commit to Scalar was on 2 October 2026. The project has 16k stars on GitHub.

Scalar: open-source alternative to Postman, ReadMe

About Scalar

Scalar is an open-source API platform built around the OpenAPI standard. One part turns OpenAPI or Swagger documents into an interactive API reference with a built-in testing tool and generated code samples for many languages and frameworks, and it aims for a modern look rather than a dated one. Integrations exist for popular server frameworks, so docs can be mounted straight into an existing project.

The other part is an API client designed to work offline and built for OpenAPI. It is free and open source, treats OpenAPI and Swagger as first-class inputs, works with dozens of API frameworks such as Elysia, Hono and FastAPI, and can stay in sync with a running server through a watch mode. Environment variables, dynamic parameters and the other staples of a REST client are included. You can try it in the browser or download it for Windows, macOS or Linux.

The quickstart even offers a prompt you can hand to a coding agent to set up the reference in your project. Scalar is MIT licensed and written in TypeScript and Vue. It suits API teams that want better-looking documentation and a lighter alternative to Postman-style tools tied to their specs.

Key features

Interactive API reference from OpenAPI documents
Built-in request testing tool
Code samples in many languages
Offline-first API client for desktop
Watch mode that syncs with server frameworks
Integrations for Hono, FastAPI and Elysia

Good fit for

→Publishing developer-friendly API documentation
→Testing APIs from an OpenAPI spec
→Replacing Swagger UI with a modern reference

Built with: TypeScript; Vue
Tags: openapi; api-documentation; api-client; swagger; typescript; vue; developer-tools; rest-api

Scalar: questions and answers

What is Scalar used for?: Scalar is an open-source API platform that renders interactive OpenAPI and Swagger references and includes an offline-first API client with desktop apps. It is a good fit for publishing developer-friendly API documentation, testing APIs from an OpenAPI spec and replacing Swagger UI with a modern reference.
Is Scalar open source?: Yes. Scalar is open source under the MIT licence. Its source code is on GitHub at scalar/scalar and is written mainly in TypeScript.
Is Scalar free?: Yes. Scalar is open source, so the software itself is free to use. Paid plans are also available, starting at $150 per month.
What is Scalar an alternative to?: Scalar is an open-source alternative to Postman, ReadMe, Stoplight and Redocly. Other open-source alternatives to Postman include Voiden, Insomnia and Mockoon.
Is Scalar actively maintained?: Yes. The most recent commit to Scalar was on 2 October 2026. The project has 16k stars on GitHub.