Top API-CLIENT GitHub Repositories & Tools (2026)

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

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

OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3)

A free, open-source developer workspace. Snippets, notes, HTTP requests, calculations, and dev tools in one local-first app.

PHP Curl Class makes it easy to send HTTP requests and integrate with web APIs

A Fork of Rikkahub with an overhauled UI and feature additions

🗜 A Ruby wrapper for the bit.ly API

The official JS client library for the Massive.com REST and WebSocket API.

Universal LLM API client — 163 providers, 14 native language bindings, powered by a Rust core

A lightweight, efficient Ruby gem for interacting with Whatsapp Cloud API.

C++23 client for Kalshi's Predictions API. Created from Kalshi's OpenAPI and AsyncAPI specs, it covers every REST operation and WebSocket channel. The WebSocket client reconnects and resubscribes. Optional transports add retries and rate limiting.

The DNSimple API client for Ruby.

Adyen API Library for PHP

Go client for Linode REST v4 API

Tetiva — desktop API client for HTTP, gRPC, GraphQL and WebSocket (Wails v3 + Vue 3)

SDKs for CoinAPI & FinFeedAPI