Hoppscotch

Hoppscotch is the open-source alternative to Postman that indie hackers have been waiting for. It's completely free, runs in your browser (no installation), supports REST, GraphQL, WebSocket, MQTT, and SSE protocols. You can use it instantly without signing up—just open hoppscotch.io and start building API requests.\n\nFor indie hackers testing and monitoring their own APIs during development, Hoppscotch's combination of lightweight UI, zero cost, and protocol breadth is unbeatable. It includes collections, environments, pre-request scripts, tests, and code generation. The open-source nature means no privacy concerns about sending your API requests through commercial servers. Self-hosting is also an option for teams building on-premises.