Contrast
Build, run, and ship real apps from your browser.
Contrast is a complete app environment in one browser tab. You edit source, run a real dev stack, preview your app on web and iOS side by side, hand work to agents, and ship to production. There is nothing to install.
Pick a path below. The quick start takes about five minutes.
Get started
Quick start
From idea to running app in five minutes.
Essentials
How projects, branches, and previews fit together.
Agents
Hand goals to the factory and review what lands.
Build
Spaces
The sections you work in, and how to move between them.
Apps
What a Contrast app is made of.
Data
SQLite and live sync, in the browser.
Launch
Publish
A live URL in one click.
Custom domains
Serve production from your own domain.
App Store
TestFlight and App Store review, guided.
Go further
Need exact commands and fields? Head to the Reference. Stuck on something? Start from Troubleshooting.
Contrast and rnx
The iOS preview in Contrast runs on rnx, a React Native simulator built for the browser. rnx also ships on its own for driving any React Native repo from the terminal. The simulator API, CLI, and package compatibility live in the rnx docs.