hoppscotch
Open-Source API Development Ecosystem • https://hoppscotch.io • Offline, On-Prem & Cloud • Web, Desktop & CLI • Open-Source Alternative to Postman, Insomnia
usebruno
Opensource IDE For Exploring and Testing API's (lightweight alternative to Postman/Insomnia)
Kong
The open-source, cross-platform API client for GraphQL, REST, WebSockets, SSE and gRPC. With Cloud, Local and Git storage.
httpie
🥧 HTTPie CLI — modern, user-friendly command-line HTTP client for the API era. JSON support, colors, sessions, downloads, plugins & more.
OpenAPITools
OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3)
massCodeIO
A free, open-source developer workspace. Snippets, notes, HTTP requests, calculations, and dev tools in one local-first app.
requestly
Community hub for Requestly API Client — bugs, feature requests, and roadmap. The privacy-first Postman alternative.
unkn0wn-root
Terminal API client for HTTP/GraphQL/gRPC with support for SSH tunnels, WebSockets, SSE, Workflows, Profiling, OpenAPI, Kubernetes port-forwarding and headless API.
mrusme
Neon Modem Overdrive (https://codeberg.org/mrus/neonmodem)
twitch4j
A JVM library for all Twitch APIs, including Chat, Helix, and EventSub (webhook/websocket/conduit). It includes advanced features for large-scale apps such as connection pooling, rate-limiting, and more!