rig
A Mac app that shows a website live in Chromium, Firefox, WebKit and iOS Simulator at once, and lets an AI agent look, measure and click on every device.
- Product, Design & Development
- Every device for coding agents
- 2026
- TypeScript
- Node.js
- Electron
- Playwright
- Astro
- Cloudflare
- Claude
The brief
Challenge
Testing a site meant opening it in one browser after another, at one size after another, and then on a phone. My coding agent could change the code, but it could not see what that did on any of those devices.
Approach
An Electron app with Playwright that opens one URL in Chromium, Firefox, WebKit and iOS Simulator side by side, live. An MCP server lets the agent take screenshots, measure elements and click, while rig blocks every request that would change the site.
Outcome
A signed and notarized alpha for Macs with Apple Silicon since October 2026, with its own site at rigapp.dev and a waitlist. I use it on my own sites.
The site
rigapp.dev says what rig does in one line and then shows the real app, screen by screen, from the agent to the simulators.
The agent looks
Claude Code checks sanderr.nl on every device that is open. Each tile it touches gets an orange ring, and the title says who is in control.
Browsers side by side
Screen sizes you add yourself, each with a switch per engine. Every switch that is on is a live tile, so one page shows up in Chromium, Firefox and WebKit at once.
Safe on a live site
- A new URL opens only after I approve it in rig
- While the agent works, every POST, PUT and DELETE is blocked
- Browsers run with their own empty profile, never mine
Real Safari on iOS
rig boots the simulators I pick from Xcode, shows them live with real taps, swipes and the iOS keyboard, and shuts them down again when it quits.
