Swell

Overview of Swell

What it is

Swell is an API development tool that enables developers to test HTTP2, GraphQL endpoints, as well as ones served over streaming technologies including Server-Sent Events (SSE), WebSockets, gRPC, WebRTC, and OpenAPI. It is open source and released under the MIT license.

Key features

• HTTP/2 multiplexing: full support for multiplexing requests and responses over a single connection, with fallback to HTTP/1.1 for legacy servers.
• GraphQL support: queries, mutations, subscriptions, and introspection, with variable support.
• Server-Sent Events (SSE): toggle to receive and display SSE events as they arrive, with multiple open connections allowed.
• WebSockets: connect to WebSocket servers via HTTP handshake, send and receive messages in real time.- gRPC: full support for unary, client stream, server stream, and bidirectional stream calls.- tRPC: support for TypeScript Remote Procedure Calls including batch calls for queries, mutations, and subscriptions.
• WebRTC: test video, audio, and text channels with manual SDP entry and generated offers/answers.

Use cases

• Testing streaming APIs that use SSE, WebSockets, gRPC, or WebRTC.
• Developing and debugging HTTP/2 and GraphQL endpoints.
• Stress testing HTTP/2 and GraphQL servers to verify load handling.
• Creating mock HTTP/2 servers for front-end development without a full backend.
• Writing assertion tests in JavaScript with Chai-style syntax for test-driven development.
• Saving and organizing multiple requests in workspaces for repeated or automated testing.

Getting started

Visit www.getswell.io to download the latest release. Swell is available for OSX, Linux, and Windows.

License and pricing

MIT License. Open source.

Based on the project's public README and repository metadata.