Best Free API Clients

The collaboration platform for API development. Simplify each step of building an API and streamline collaboration so you can create better APIs—faster. Postman is a collaboration platform for API development. Postman's features simplify each step of building an API and streamline collaboration so you can create better APIs—faster. Quickly and easily send REST, SOAP, and GraphQL requests directly within Postman. Automate manual tests and integrate them into your CI/CD pipeline to ensure that any code changes won't break the API in production. Communicate the expected behavior of an API by simulating endpoints and their responses without having to set up a backend server. Generate and publish beautiful, machine-readable documentation to make your API easier to consume. Stay up-to-date on the health of your API by checking performance and response times at scheduled intervals. Provide a shared context for building and consuming APIs, and collaborate in real-time.

Bruno is an open-source, local-first API client for exploring, testing, and documenting APIs. With native Git sync, offline data storage, and no cloud dependencies, Bruno offers developers a secure, fast, and open alternative to bloated API platforms. Trusted by 150 k+ daily users and loved by 37 k+ GitHub stargazers. Pure API Client — Bruno is not a platform or cloud SaaS. It’s a lightweight desktop app focused purely on exploring, testing, and documenting APIs — no unnecessary clutter. Local-First Security — All your data and collections stay on your machine. Nothing is synced to a third-party cloud, ensuring complete control and compliance. Native Git Sync — Collaborate and version your collections using the same workflows you already use for code — pull requests, branches, and diffs — with no proprietary lock-in. Open Source & Extensible — Backed by a passionate community, Bruno evolves transparently, with frequent contributions from developers across the world

Design, debug, and test APIs like a human, not a robot. Finally, a workflow you'll love. The Collaborative API Design Tool for designing, testing and managing OpenAPI specifications. The Desktop API client for REST and GraphQL. Make requests, inspect responses. Quickly create and group requests, specify environment variables, authentication, generate code snippets, and more. Get all the details on responses. View the whole request timeline, status codes, body, headers, cookies, and more. Create workspaces, folders, environments, drag-and-drop requests, and easily import and export your data. Create, edit, lint, debug, preview, and manage all of your OpenAPI specs in one collaborative API design editor. Generate configuration for common API gateways such as the Kong API Gateway, and Kong for Kubernetes. Sync your API designs with source control such as Github / Gitlab, and deploy directly to API Gateways such as Kong with one click.

From powerful API client features to advanced testing and monitoring, Testfully does it all. Enjoy the flexibility of cloud and offline-only storage, seamless team collaboration, and easy migration, all in one multi-platform tool. Easily transfer your data from Postman or Insomnia directly into Testfully. Flexible and secure, set global, environment, and folder variables scoped to workspace or user. Customize auth, parameters, headers, and body to build any HTTP request easily. Work together effortlessly, add teams, assign roles, and control folder access. Supports major schemes like OAuth2 for secure and streamlined authorization. From basic to complex, Testfully enables quick, effective testing without the need for coding, making advanced API testing accessible and hassle-free. Execute all requests in a folder simultaneously, sequentially, or randomly with just one click. Validate responses and perform contract testing using a declarative format, no coding is needed.

Kiota is a client, plugin, and manifest generator for HTTP REST APIs described by OpenAPI. Available as a command-line tool and a Visual Studio Code (VS Code) extension, Kiota enables developers to search for API descriptions, filter and select specific endpoints, and generate models and a chained method API surface in various programming languages. This approach eliminates the need to depend on different API clients for each API and allows for precise generation of the required API surface area. Additionally, Kiota facilitates participation in the Microsoft Copilot ecosystem by enabling the generation of API plugins. The VS Code extension enhances the Kiota experience with a rich user interface, supporting features such as searching for API descriptions, filtering endpoints, and generating API clients. Users can select desired endpoints and generate clients, plugins, or other outputs, with completion notifications and easy access to generated outputs within the workspace.

Hoppscotch makes it easy to create and test your APIs, helping you to ship products faster. Create APIs faster, test them instantly, document and share them automatically. From prototyping to production - develop without switching tabs. Hoppscotch got everything you need to make API development easy. Create workspaces for your teams. Control access to your workspaces. Work together with your team in real-time. Deploy Hoppscotch on your own servers. Organize your requests in collections or folders and share them with your team. Manage your environment variables and use them everywhere. View and manage your request history. Modify headers, authenticate requests, generate random data, and much more. Test your APIs and write assertions for the response. Use Hoppscotch in your native language. We support 30+ languages. Track all the activities in your workspace. Who did what and when. Use your existing SSO provider to login to Hoppscotch. Manage your users, workspaces, and more.

​Thunder Client is a lightweight REST API client extension for Visual Studio Code, designed to simplify API testing with an intuitive and user-friendly interface. It supports features such as collections, environment variables, and scriptless testing, allowing developers to organize requests, manage different environments, and validate API responses without the need for scripting. All data is stored locally on the user's device, ensuring privacy and security. Additionally, Thunder Client offers Git synchronization for team collaboration, enabling the saving and sharing of request data within a Git repository. Its CLI supports CI/CD integration, facilitating automated testing and report generation. Trusted by over 5 million users worldwide, Thunder Client seamlessly integrates into the VS Code environment, providing a streamlined workflow for API development and testing. ​

GetAPI is a lightweight, native macOS HTTP client designed to simplify the process of making and testing REST API calls through a clean and minimal interface. Built as an alternative to tools like Postman or Insomnia, it allows developers to import existing collections, send HTTP requests, and instantly view structured responses without unnecessary complexity or setup. It is developed specifically for macOS using native technologies such as Swift and Objective-C, ensuring fast performance, smooth integration with the operating system, and a polished user experience. It supports essential API testing workflows, including request composition, navigation between requests, and quick inspection of response data, while maintaining a streamlined approach focused on speed and usability. GetAPI operates entirely locally, does not collect or sync user data to the cloud, and emphasizes privacy and control over sensitive API information.

Scalar is a modern, open source API platform designed to help developers create, document, test, and manage APIs through a unified, interactive environment built around the OpenAPI standard. It transforms OpenAPI specifications into clean, visually appealing, and interactive API documentation that allows users to explore endpoints and test requests directly within the interface, combining documentation and a full-featured API client in one place. It includes a built-in REST API client that supports sending requests, inspecting responses, handling authentication methods such as API keys and OAuth2, and working with environment variables and dynamic parameters. Scalar also offers tools for generating SDKs, managing and versioning API specifications with Git integration, and creating documentation that stays synchronized with the underlying API through Markdown or MDX workflows.

RapidAPI for Mac is a powerful HTTP client designed specifically for macOS, enabling developers to test, build, and document APIs in one intuitive interface. It allows users to send various HTTP requests, inspect server responses, and iterate quickly during development. With its clean and native macOS design, developers can easily compose requests and manage API workflows without complexity. The tool also supports API description using JSON Schema and integrates with standards like Swagger and RAML. It simplifies API development by combining testing and documentation in a single environment. Developers can generate client code and export API definitions seamlessly. Overall, RapidAPI for Mac helps streamline API development with speed and efficiency.

Requestly API Client offers a range of tools to help you design, manage, and test APIs effectively. With distinct combination of features Requestly acts as a companion to developers and QAs. 1. Design APIs: Requestly simplifies API Design by allowing you to create individual API requests, specify HTTP methods, headers, query parameters, and request bodies. 2. Send API Requests: Sending API Requests is at the core of API testing. Responses can be viewed in detail, including status codes, headers, and payloads. 3. API Collections: Collections allow you to group related API requests for better organization and collaboration. 4. Variables: Requestly simplify API testing and management by allowing you to replace hardcoded values with placeholders - Collection, Environment, and Global Variables. 5. Scripts (Pre & Post): Scripts allow you to add logic or modify requests before they are sent, or process responses and manipulate variables that can be used in subsequent API call.