Overview

What is APEX API?

APEX API is a free, open-source API development platform designed as a powerful alternative to commercial tools like Postman. Built as a Progressive Web App (PWA), APEX lets you build, test, and document APIs directly from your browser or install it as a native desktop application. Whether you are working with REST, GraphQL, WebSocket, Server-Sent Events, or MQTT protocols, APEX provides a unified interface for all your API interactions.

Key Features

• Multi-Protocol Support — Send HTTP requests, execute GraphQL queries, manage WebSocket connections, stream SSE events, and publish/subscribe via MQTT — all from one interface.
• ApexScript — A built-in scripting language for pre-request scripts and test assertions. Automate workflows with a familiar JavaScript-like syntax.
• Code Forge — Instantly generate API client code in 20+ programming languages. Convert any request into production-ready code snippets.
• Signal Groups & Command Centers — Organize your requests into collections (Signal Groups) and manage team workspaces (Command Centers) for collaborative API development.
• Environment Contexts — Define variables per environment (development, staging, production) and switch between them seamlessly with the double-brace {{variable}} syntax.

Why Open Source?

APEX is built by developers, for developers. We believe API tooling should be transparent, extensible, and community-driven. Being open source means you can audit the code, extend functionality with plugins, self-host for your team, and contribute features that matter to you. There are no vendor lock-ins, no arbitrary feature gates, and no data silos. Your API workflows remain entirely under your control.

Architecture

APEX is built with Next.js 16, TypeScript, and a modern React component architecture. The app uses Zustand for state management, Prisma for local data persistence, and supports both browser-based PWA usage and native desktop installation via Tauri. All data is stored locally on your device by default, ensuring privacy and offline access to your saved requests and collections.