Best Nonprofit 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.

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. ​

🚀 PostPilot – Your Private Workspace for APIs, Databases & Data Inspection PostPilot combines an API client, database client, and data inspector into one streamlined, local-first interface. Use Variables to link requests and organize everything in reusable Collections — fully local, fully private. ⚙️ How PostPilot Streamlines Your Development Workflow PostPilot combines three core tasks into one lightweight, local app: - API Testing: Send REST/GraphQL requests, inspect responses, and extract data. - Database Querying: Connect to your local or remote DBs and run SQL queries. - Data Inspection: Load JSON/XML, run queries, and debug data fast. All with: - Connection via Variables: Easily reuse variables across requests, queries, and scripts. - Manage requests in Collections: Save and reuse requests anytime - Private Workspace: Your data stays local. No cloud sync, no tracking.

Hubql is your local-first API Client to test, share, document and ship APIs faster. Start with any OpenAPI spec either through introspection via URL or using our server libraries passing your API schema. Hubql is built as local-first library storing your data offline. Our API client runs in browser only either as a local server plugin for example as NestJS plugin or distributed directly via CDN as JS library. Organize your APIs in workspaces and Hubs. Share your API Hubs with your team members and collaborate on the same API collection. Store your environment variables in your workspace and use them in your API requests. No need to copy-paste your variables anymore.