API Development & Testing

Scalar is an open-source API platform:　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　🌐 Modern REST API Client　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　📖 Beautiful API References　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　✨ 1st-Class OpenAPI/Swagger Support

The open-source solution to building, maintaining, and collaborating on GraphQL Federation at Scale. The alternative to Apollo Studio and GraphOS.

Build product integrations with AI.

A lightweight AWS service emulator written in Go

The Developer Platform for Modern APIs

Opensource IDE For Exploring and Testing API's (lightweight alternative to Postman/Insomnia)

The open-source, cross-platform API client for GraphQL, REST, WebSockets, SSE and gRPC. With Cloud, Local and Git storage.

Open-source API development suite for contract-first testing and specification-driven workflows.

Blazing fast, instant realtime GraphQL APIs on all your data with fine grained access control, also trigger webhooks on database events.

Envoy-based MCP gateway with auth and policy integration.

Open-Source API Development Ecosystem • https://hoppscotch.io • Offline, On-Prem & Cloud • Web, Desktop & CLI • Open-Source Alternative to Postman, Insomnia

The Cloud-Native API Gateway and AI Gateway

Native AI gateway and LLM proxy built in Rust.

The open source, cloud native tool for API Mocking and Testing. Microcks is a Cloud Native Computing Foundation sandbox project 🚀

Testcontainers for Go is a Go package that makes it simple to create and clean up container-based dependencies for automated integration/smoke tests. The clean, easy-to-use API enables developers to programmatically defi

API laboratory for designing and testing API workflows.

Gravitee.io - OpenSource API Management

An interactive TLS-capable intercepting HTTP proxy for penetration testers and software developers.

AI-first IDE for QA and API testing.

Lightweight self-hostable API client with no cloud or telemetry.

NyaProxy acts like a smart, central manager for accessing various online services (APIs) – think AI tools (like OpenAI, Gemini, Anthropic), image generators, or almost any web service that uses access keys. It helps you use these services more reliably, efficiently, and securely.

KrakenD Community Edition: High-performance, stateless, declarative, API Gateway written in Go.

Free and open-source API Client & Interceptor.

justoneapi数据接口服务。提供：淘宝、小红书、拼多多、同程旅行、京东外卖、抖音（电商）、美团、抖音（视频）、快手、蒲公英、星图、微信公众号、大众点评、哔哩哔哩、知乎、微博、贝壳、Bigo、Temu、Lazada、Shopee、SHEIN、百度指数、携程、Boss直聘、智联招聘、拉钩、今日头条、Facebook、Youtube、Instgram、Twitter。爬虫、采集、scrapy、接口、API。

🦍 The API and AI Gateway

Hurl, run and test HTTP requests with plain text.

Kubernetes-native API gateway for microservices built on Envoy Proxy.

High Performance GraphQL Runtime

Ultra performant API Gateway with middlewares. A project hosted at The Linux Foundation

Open-source cross-platform functional testing tool for APIs, SOAP services, REST endpoints, and web services.

API Dash is a beautiful AI-powered open-source cross-platform (Desktop & Mobile) API Client built using Flutter which can help you easily create & customize your HTTP & GraphQL API requests, visually inspect responses and generate API integration code. A lightweight alternative to postman/insomnia.

⚓️ Easily test HTTP webhooks with this handy tool that displays requests instantly.

A Cloud Native traffic orchestration system

Offline-first HTTP and socket API testing client for web and desktop.

Cloud native, ultra-high performance AI&API gateway, LLM API management, distribution system, open platform, supporting all AI APIs.🦄云原生、超高性能 AI&API网关，LLM API 管理、分发系统、开放平台，支持所有AI API，不限于OpenAI、Azure、Anthropic Claude、Google Gemini、DeepSeek、字节豆包、ChatGLM、文心一言、讯飞星火、通义千问、360 智脑、腾讯混元等主流模型，统一 API 请求和返回，API申请与审批，调用统计、负载均衡、多模型灾备。一键部署，开箱即用。

💻 A fully functional local AWS cloud stack. Develop and test your cloud & Serverless apps offline

🔒 Enterprise-grade API gateway that helps you monitor and impose cost or rate limits per API key. Get fine-grained access control and monitoring per user, application, or environment. Supports OpenAI, Azure OpenAI, Anthropic, vLLM, and open-source LLMs.

Open-source webhook gateway for Stripe, GitHub, and Slack.

Next-generation AI model API aggregation and distribution system.

LLM API 管理 & 分发系统，支持 OpenAI、Azure、Anthropic Claude、Google Gemini、DeepSeek、字节豆包、ChatGLM、文心一言、讯飞星火、通义千问、360 智脑、腾讯混元等主流模型，统一 API 适配，可用于 key 管理与二次分发。单可执行文件，提供 Docker 镜像，一键部署，开箱即用。LLM API management & key redistribution system, unifying multiple providers under a single API. Single binary, Docker-ready, with an English UI.

No-code API wrapper for databases.

Open-source test automation tool for web, mobile, and API testing.

An open-source, lightweight API Gateway built on Express.js

Open-source cross-platform API test and design client.