Best Free & Open Source Alternatives to Postman

Looking for a free or self-hosted alternative to Postman? Below you'll find the best open source options — community-driven tools that let you own your data without vendor lock-in or recurring subscription costs.

Postman is an all-in-one API platform that helps developers design, build, test, document, and monitor APIs. It provides an easy-to-use interface for sending requests, inspecting responses, and automating workflows, making it a go-to tool for working with APIs of any size or complexity.

Beyond simple request testing, Postman supports the full API lifecycle. Teams can collaborate in shared workspaces, create mock servers, automate tests, generate documentation, and integrate with CI/CD pipelines. Its robust set of tools and integrations streamlines API development and ensures consistency, security, and scalability across projects.

Insomnia

The open-source, cross-platform API client for GraphQL, REST, WebSockets, SSE and gRPC. With Cloud, Local and Git storage.

Alternative to:

Postman

Bruno

Opensource IDE For Exploring and Testing API's (lightweight alternative to Postman/Insomnia)

Alternative to:

Postman

Hoppscotch

Open source API development ecosystem - https://hoppscotch.io (open-source alternative to Postman, Insomnia)

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Postman

Scalar

Scalar is an open-source API platform:　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　🌐 Modern Rest API Client　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　📖 Beautiful API References　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　✨ 1st-Class OpenAPI/Swagger Support

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Postman

HTTPie

🚀 HTTPie Desktop — cross-platform API testing client for humans. Painlessly test REST, GraphQL, and HTTP APIs.

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Postman

Yaak

The most intuitive desktop API client. Organize and execute REST, GraphQL, WebSockets, Server Sent Events, and gRPC 🦬

Alternative to:

Postman

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