11 Open Source Alternatives to Postman

Hoppscotch empowers developers to rapidly create, test, and document APIs with an intuitive interface and collaborative workspaces. The platform supports multiple protocols such as HTTP, GraphQL, WebSocket, and more, across web, desktop, and CLI environments. Features like real-time collaboration, pre-request scripting, code snippet generation, and on-prem deployment streamline workflows, enabling both individuals and organizations to boost productivity and efficiency.

HTTPie simplifies working with HTTP servers, RESTful APIs, and web services via a sleek CLI experience. It provides syntax highlighting, session capabilities, and an extendable plugin system that enhances daily API testing and development workflows. The tool is available for Terminal and also as a desktop application, ensuring flexibility across environments.

Mockoon offers an intuitive interface that allows you to design, run, and debug mock APIs in seconds. With advanced features such as dynamic templating, rules matching, multiple response modes, HTTPS support, and proxy mode, it integrates seamlessly into any API design workflow. Enjoy compatibility with OpenAPI, CLI, Docker, serverless environments, and even cloud deployments via Mockoon Cloud for real-time collaboration.

Insomnia empowers developers to create, organize, and execute API requests efficiently across various protocols. Its intuitive design-first approach and built-in automation support rapid API development, live previews, and code generation. With local vaults, Git sync, and a diverse plugin ecosystem, it fosters collaborative and secure API workflows.

Scalar enables you to create world-class API docs with an interactive playground that transforms into a full-featured API client. The platform integrates effortlessly with various frameworks and supports Git and Markdown syncing, custom HTML/CSS/JS, and offline functionality. Its design caters to web, macOS, Linux, and Windows environments, reducing onboarding time and enhancing developer productivity.

Bruno provides a fully offline environment that ensures your API data stays secure and local. With its Git-integrated workflow, developers can version, share, and collaborate on API collections directly from their preferred version control system. This tool emphasizes speed, low memory consumption, and a focus on essential testing features without unnecessary platform bloat.

Yaak is built for speed and privacy using Rust and ReactJS, delivering seamless API testing on Mac, Windows, and Linux. It stores data as plain text for effortless Git integration and extends functionality through NodeJS plugins. With support for dynamic requests, multi-window multitasking, and diverse authentication methods, Yaak makes collaborating on API development and testing efficient and intuitive.

Firecamp offers a comprehensive suite of tools for API development, including dedicated playgrounds for REST, GraphQL, and more. It enables users to manage API collections, run visual tests, and collaborate in a centralized workspace. The platform also includes features for API documentation, dynamic variable management, authentication testing, and CLI/CI/CD integration, available on both web and desktop applications.

Requestly empowers developers and QA engineers to independently build and test APIs by offering easy-to-use features for API testing, mocking, and real-time request modification. The tool supports various operating systems through browser extensions and desktop applications, facilitating HTTP interception, environment switching, and team collaboration in dedicated workspaces while ensuring enterprise-grade security compliance.

Karate simplifies testing by combining API, performance, mocks, and UI automation into one unified framework. It uses a language-neutral, domain-specific language based on Gherkin, enabling easy creation of readable tests, dynamic data-driven execution, and reusable feature calls. Built-in assertions, HTML reports, and parallel execution help teams quickly identify issues and integrate testing seamlessly with build tools and IDEs.

Milkman offers a versatile environment for building and organizing requests across different technologies including HTTP REST, databases, GRPC, GraphQL, and more. Built on JavaFx, it emphasizes speed and efficient resource usage. With a plugin-based design, the tool is constantly evolving through new features and community contributions.