Testing Data Streams Just Got A Lot Easier

Testing for streaming APIs, right at your desktop.

Your one-stop shop for sending, monitoring, and testing RESTful, gRPC, GraphQL, Websocket, OpenAPI, WebRTC, Webhooks, and streaming API requests. Now with increased security and Github integration.

Check out our Github
swell dashboard

All the protocols you'll ever need.

Multiple streams. A single connection.


Swell supports full HTTP2 multiplexing of requests and responses. HTTP requests to the same host will be sent over the same connection. Swell will attempt to initiate an HTTP2 connection for all HTTPS requests by default, but will revert to HTTP1.1 for legacy servers. Multiple concurrent streams are allowed for each connection.

Stay connected.

Server-sent Events (SSEs)

Initiated by a simple toggle box, Swell displays SSE events one by one as they come in. Similar to HTTP/2 streams, multiple open connection streams are allowed for SSE. **Currently being optimized for a future release**

Keeping in touch

Web Sockets

Swell enables connecting directly to WebSocket servers with an HTTP handshake. Developers can directly send data to the connected WS server in the form of simple strings or binary data. Messages and images are displayed in chatbox format, clearly indicating outgoing and incoming messages.

Queries, Mutations, Subscriptions


Swell includes full support for all three root types of GraphQL — queries, mutations, and subscriptions as well as Introspection - with and without variables. Smart code editor allows for easy query creation.

Bring Your Own Proto (BYOP)


Swell includes full support for all four streaming types of gRPC - unary, client stream, server stream, bidirectional stream. **Currently being optimized for a future release**

Built In Test Suite Editor


Compose test suites in JavaScript with built in Chai-style TDD/BDD assertion syntax. Tests will resolve on response data and all results will appear in the new Test Response pane. **Currently being optimized for a future release**

Advanced Testing Capabilities


Connect to a Websocket server and test with a variety of data types: binary data (i.e. Binary Large oBjects or array buffers) and strings. Conveniently write mocha/chai assertion tests on data transfers. Further, export data logs as well as measure client/server latency. **Currently being optimized for a future release**


WebRTC and OpenAPI 3.1

Make API requests based on a range of provided options that are generated according to specifications defined in a yaml or json-formatted OpenAPI document. Plus, test WebRTC signaling by verifying ICE candidates and generating an SDP. **Currently being optimized for a future release**

WIP Features: Coming soon!

Additional Testing Capability

WebHook Testing

Swell includes user-defined HTTP callback connection testing designed to test other server's connection to the web and ability to send data. The test insures that when an event occurs, the source site makes an HTTP request to the URL configured for the Webhook. **Currently being optimized for a future release**

export workspaces
New, Smooth UI

Built with Material UI

A smoother, more intuitive interface for enhanced user experience. Use a navbar to switch protocols, a smoother workspaces container, and find some extra room to breathe.

Workspace Collaboration + Github Integration

Save, Export, and Share Workspaces

You will now be able to save your workspaces and export them to your local machine. Even register with Github to save workspaces to your repository for easy collaboration!

swell logo

Get Swell Desktop App

The desktop distribution is suggested for Mac, Linux, and Windows users.


Alexa Nunes


HyeJin Kim


Michael Smith


Travis Lovis


Evelin Goldin


Alexander Adams


Yale Yng-Wong


Ethan Sclarsky


Genevieve Annable


Drew Pomatti


Sam Pyo


Jay Wall


Kurtis Waterbury


Christopher Pan


Michael Prince


Adrian Uesugui


Jacob Viesselman


Jennifer Wu


Ted Craig


Anthony Wong


John Jongsun Suh


Colin Gibson


Paul Ramirez


Nathan Fleming


Andrea Li


TJ Wetmore




Edward Cho


Jason Liggayu


Miguel Gonzalez


Warren Tait


Nathaniel Adams


Sam Haar


Gary Slootskiy


Robin Yoong


Grace Kim


Alex Sanhueza


Wyatt Bell


John Madrigal


Michael Miller


Grace Spletzer


Hideaki Aomori


Nick Healy


Matt Gin


Stephanie Wood


Kyle Combs


Jason Ou


Anthony Terruso


Brandon Marrero


Kwadwo Asamoah


Abby Chao


Amanda Flink


Kajol Thapa


Billy Tran


Paul Rhee


Sam Parsons


Yoon Choi


Nancy Dao


Evan Grobar


Dan Stein


Amruth Uppaluri