Open-source Apifox alternatives

Hoppscotch is an open-source API development ecosystem for sending requests, inspecting responses and organizing API work. It is positioned as an alternative to Postman and Insomnia and runs in the browser, as a desktop app and from a command line interface, with offline, on-premises and cloud options.

The request builder supports the standard HTTP methods plus custom ones, and the toolset extends to GraphQL and WebSocket testing. You can generate code snippets for more than ten languages and frameworks, share requests through public URLs, and install the web app as a progressive web app for offline use. The interface is lightweight, with light, dark and black themes, a choice of accent colors and a distraction-free Zen mode.

Hoppscotch is MIT licensed and written mainly in TypeScript with Vue. Teams that need to keep API traffic and collections inside their own network can self-host it, while the hosted service at hoppscotch.io suits individuals who just want to start sending requests.

Bruno is an open-source API client and testing environment, described as a lightweight alternative to Postman and Insomnia. It supports REST, GraphQL, gRPC and WebSocket requests, and runs on macOS, Windows and Linux.

Its distinguishing idea is that collections live directly in a folder on your filesystem, saved in a plain text markup language called Bru. That means you can version and share API collections with Git or any version control system you already use. Bruno is offline only, and the maintainers state they have no plans to add cloud sync, because they believe your data should stay on your device. A CLI runs collections from the command line for automated testing and CI/CD, and a Docker option is also documented.

The core is MIT licensed, and the project offers paid versions that add further features for teams that want them. Bruno can be installed from the website or through Homebrew, Chocolatey, Scoop, Snap, Flatpak and Apt. It suits developers who prefer keeping API definitions next to their code.

Insomnia is an API client from Kong that is open source and runs on every major desktop platform. It handles GraphQL, REST, WebSockets, Server-Sent Events, gRPC and other HTTP-compatible protocols, so one desktop app can cover most of the API work a developer does day to day.

With it you can debug requests, design APIs in a native OpenAPI editor with visual preview, test them with native test suites and a collection runner, and mock them with a cloud or self-hosted mock server. A command line tool supports linting and testing in CI/CD pipelines, collaboration features help teams share work, and third-party plugins extend the app. Projects can be stored in a Local Vault for fully local use, synced through any Git repository, or kept in the cloud with optional end-to-end encryption.

Insomnia is Apache-2.0 licensed and written in TypeScript on Electron. It is free to get started with, and paid collaboration features are available from the vendor. It is a popular alternative to Postman for developers who want flexible storage options.

Yaak is a desktop API client for building, sending and inspecting requests to REST, GraphQL, gRPC, WebSocket and Server-Sent Events endpoints. It is built with Tauri, Rust and React and works offline-first, with no telemetry and no requirement to sync data to a cloud account.

Collections from Postman, Insomnia, OpenAPI, Swagger or curl can be imported. Responses can be filtered with JSONPath or XPath, and authentication supports OAuth 2.0, JWT and Basic Auth, with encrypted secrets that can be kept in the operating system keychain. Requests are grouped into workspaces and nested folders, and environment variables switch between dev, staging and production.

Workspaces can be mirrored to the filesystem so they can be versioned in Git or synced with a file-sync service. Template tags insert dynamic values such as UUIDs or timestamps, and themes and plugins allow customization. Yaak is MIT licensed, its repository topics position it as an alternative to Postman, Bruno and Insomnia, and development is funded by community-purchased licenses.

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.

Mockoon is an open-source tool for designing and running mock APIs. It combines a desktop application for building mock servers locally with a command-line tool for running those mocks in headless environments, and it requires no remote deployment or account.

API mocking reduces dependence on external services and their limits such as rate limits, costs and availability. Mockoon lets you control routes in detail, including HTTP methods and statuses, regex paths, file serving and custom headers. It supports OpenAPI import, JSON templating, HTTPS, a proxy forwarding mode and logs of incoming and forwarded requests. Teams can simulate errors and latencies and onboard new members with a consistent test environment.

The desktop app is built with Electron and TypeScript under the MIT licence and installs through Homebrew, winget, Chocolatey, the Windows Store, Snap or AUR. The CLI is also available as a Docker image for self-hosting mock APIs, and a separate cloud offering supports team collaboration, data sync and deployment of mock APIs.

API Dash is an open-source API client for desktop and mobile, built with Flutter and described as a lightweight alternative to Postman and Insomnia. You can create and customize HTTP and GraphQL requests, visually inspect the responses, and generate code for integrating an API into your application. It is released under the Apache-2.0 license and includes AI-assisted features.

Requests can be built with different HTTP methods, headers, query parameters, and bodies, and the app handles Unicode and emoji content in both requests and previews. Requests are organized into collections and folders that you can rearrange, rename, and duplicate. Collections can be imported from Postman, cURL, Insomnia, OpenAPI, and HAR files, and the topics also mention server-sent events and WebSocket support.

Builds are provided for iOS, macOS, Windows, and Linux in several package formats. It suits developers who want a free, native-feeling alternative for exploring and testing APIs and who may want to contribute, since the project takes part in open-source programs and welcomes contributors.

Voiden is an offline API client for developers, QA engineers, and technical writers to build, test, collaborate on, and document APIs in one place. APIs are described in plain-text .void files that you keep in Git, with no account and no required cloud sync. It is built with Electron and TypeScript and released under the Apache-2.0 license.

Requests are composed from reusable API blocks that can be replaced and versioned like code, with a slash-command interface and a command-line tool designed to work with AI agents. It supports REST, GraphQL, gRPC, and WebSocket protocols, imports OpenAPI, and topics mention an MCP client. The project says it has no telemetry, no venture funding, and no cloud lock-in.

Voiden is positioned as an alternative to Postman, Bruno, and Insomnia. It suits teams who want their API collections and documentation to live in the repository as files that can be reviewed and shared through normal Git workflows.

Firecamp is a developer-focused API platform for designing, developing, testing and documenting APIs. It is presented as an open-source alternative to Postman and Insomnia, with an interface inspired by the developer experience of VS Code.

It handles several protocols in one tool, including REST, GraphQL, WebSocket and Socket.IO, with playgrounds for each. Teams can organize requests into collections and work in a shared workspace. Other capabilities include authentication testing, pre-request and test scripts, dynamic variables, and documentation, command-line and CI/CD tooling kept under the same roof.

Desktop applications are available for macOS on Intel and Apple Silicon, Windows and Linux AppImage, and you sign in through firecamp.dev to get started. The code is TypeScript and licensed under AGPL-3.0, and the latest release listed is a beta of version 3.3.

HTTPie Desktop is a desktop application for testing REST, GraphQL and general HTTP APIs, built by the team behind the HTTPie command-line tool. It is aimed at developers who want a graphical client for exploring and testing APIs rather than working purely from the terminal or a web-only tool.

The repository publishes prebuilt releases of the app for macOS, Windows and Linux, and the installed application auto-updates after the initial install. On Linux it is distributed as an AppImage, which the project recommends running through AppImageLauncher rather than executing directly. A web app version is also available at httpie.io/app or through the req.new shortcut.

The repository metadata lists the project's license as Other, so check the license terms before relying on it for commercial use. It is a packaged, closed-source-adjacent distribution of releases rather than a buildable open-source codebase in this particular repo, and users looking for ongoing feature changes should follow the release notes linked from the project.