CustappChat. Build. Improve.
Stream answers, create HTML apps, test them in an isolated preview, and edit them with AI.
YOUR CHROME WORKSPACEIdeas become apps.
Ideas become apps.
Right in your browser.
Chat with AI, build real apps, and work with the pages you already have open. Your Chrome owns the workspace.
v0.1.1 · Chrome 120 or later · Direct install
YOUR IDEAS, MADE REALWhat will you
What will you
build today?
Build a habit tracker with weekly progress…
Create ↗Habit tracker ↗Point of sale ↗A little game ↗
Your browser, connected.
Read open pages, use browser tools, and connect MCP servers. Review actions before they run.
A companion of its own.
Use Chrome independently or connect it to Custapp Web. Choose a native companion when you need its tools.
A few steps.
Your own workspace.
- 1
Download and extract
Download the ZIP above, then extract it to a folder you will keep on your computer.
- 2
Load Custapp in Chrome
Open
chrome://extensions, turn on Developer mode, then choose Load unpacked. Select the extracted folder containingmanifest.json. - 3
Choose your AI
Pin Custapp and open its side panel. In Settings → Add AI, choose your provider, enter your key, and discover or enter the exact model. You can start local chat and app building without a Custapp account.
Connect Custapp Web
Sign in with Google in the extension’s Settings, then open Custapp Web and enter your username. Confirm the connection using the approval code shown in the extension. Keep Chrome open and its companion connected.
Update without deleting your workspace
Keep your existing extension folder. Replace its contents with the new package, then click Reload on its card at chrome://extensions. Keep the folder in the same location and keep using the same Chrome profile.
Use a native companion
In Settings, choose Native companion · C-Router, then supply that companion’s URL, key, and advertised model. Chrome keeps your conversation while the selected companion runs its harness.