Ship browser extensions in minutes

Chat with AI to create production-ready browser extensions. See live previews, iterate in real-time, and ship to Chrome, Edge, and Firefox stores in minutes.

No credit card required. Build your first extension in under 5 minutes.

extendable.app
U
Make an extension that shows word count in the sidepanel
AI
Building your extension...
+ manifest.json
+ sidepanel.html
+ sidepanel.js
| content.js
$ Describe your extension...
Live Preview

Features

Everything you need to ship extensions

From idea to Chrome Web Store in minutes, not weeks. Extendable handles the complexity so you can focus on your extension's value.

Chat-Driven Development

Describe your extension in natural language. Our AI understands browser APIs, manifest v3, and extension best practices.

Live VNC Preview

See your extension running in a real Chromium browser. Test clicks, popups, and sidepanels in real-time.

Cloud Sandboxes

Extensions build and run in isolated E2B sandboxes. No local setup required - start building in seconds.

Iterative Refinement

Not quite right? Keep chatting to refine. Add features, fix bugs, and polish your extension conversationally.

One-Click Export

Download your extension as a ready-to-submit ZIP file. Includes manifest, icons, and all required assets.

Manifest V3 Ready

All extensions use the latest Manifest V3 format, ensuring compatibility with Chrome Web Store requirements.

How It Works

From idea to store in 5 steps

No boilerplate, no documentation diving, no debugging chrome.tabs errors. Just describe, build, and ship.

01

Describe Your Extension

Tell the AI what you want to build. "Create an extension that shows word count in the sidepanel" is all you need.

Chat
Create an extension that shows a word count tracker in the sidepanel
I'll help you build that! Let me create:
• manifest.json with sidepanel permissions
• sidepanel UI with counter display
• content script to analyze pages
02

Watch It Build

AI writes manifest.json, background scripts, content scripts, and UI. See progress in real-time.

Chat
✓ Created manifest.json
✓ Built sidepanel.html with UI
✓ Added content script for counting

Your extension is ready to test!
03

Test in Live Browser

Your extension loads automatically in a cloud Chromium instance. Click, test, and interact through VNC preview.

chrome://extensions

Word Counter

Extension ID: abcdefgh...

Sidepanel showing: 1,247 words
04

Iterate & Refine

Not perfect? Keep chatting. "Add a dark mode toggle" or "Fix the popup width" - AI handles the changes.

Chat
Can you add a dark mode toggle?
Absolutely! I'll add:
• Dark mode toggle button
• Theme switching logic
• CSS variables for both themes
05

Export & Publish

Download your extension as a store-ready ZIP. Submit to Chrome, Edge, or Firefox with confidence.

chrome://extensions

Word Counter

Extension ID: abcdefgh...

✓ Built and ready to download

Market Opportunity

Reach billions of users

Browser extensions are one of the most underrated distribution channels. Build once with Extendable, deploy to every major browser store.

C

Chrome Web Store

3.4B+

monthly active users

188K+

extensions published

M

Microsoft Edge

360M+

monthly active users

10K+

extensions published

F

Firefox Add-ons

178M+

monthly active users

33K+

extensions published

The extension market is growing 15% year-over-year. Get your idea in front of users today.

Use Cases

Build any extension you can imagine

From simple utilities to complex tools, Extendable handles popups, sidepanels, content scripts, background workers, and more.

Productivity

Tab Manager

"Build an extension that groups tabs by domain and lets me save/restore tab sessions"

Developer Tools

API Inspector

"Create a sidepanel that shows all network requests with response times and payloads"

Content

Reading Mode

"Make an extension that strips ads and reformats articles for easy reading"

Social

Screenshot Tool

"Build an extension to capture visible page or full-page screenshots with annotation"

E-commerce

Price Tracker

"Create an extension that tracks Amazon prices and alerts when they drop"

Accessibility

Text-to-Speech

"Build an extension that reads selected text aloud with adjustable speed"

FAQ

Frequently asked questions

Everything you need to know about building extensions with Extendable.

Do I need to know how to code? +
No coding experience required. Describe what you want in plain English, and the AI handles the implementation. However, developers can still dive into the generated code to customize further.
What browsers are supported? +
Extensions built with Extendable use Manifest V3 and are compatible with Firefox, Chrome, Microsoft Edge, Brave, Opera, and other Chromium-based browsers.
Can I export and modify the code? +
Absolutely. You own the code. Export your extension as a ZIP file containing all source files. You can modify, extend, or use it as a starting point for more complex projects.
How does the live preview work? +
Your extension runs in a cloud-hosted Chromium browser powered by E2B sandboxes. You interact with it through a VNC connection in your browser - click buttons, test popups, and see real behavior.
What AI model powers Extendable? +
Extendable uses Claude Code CLI, Anthropic's AI coding assistant. It understands browser extension APIs, Manifest V3 requirements, and modern JavaScript best practices.
Is there a free tier? +
While in beta, yes! You can build and test extensions for free. You'll need to provide your own Anthropic API key for AI generation. We plan to offer bundled API credits in the future.
Can I publish directly to stores? +
Yes! After the first store submission (which must be done manually), Extendable will deploy updates directly to the stores. Extendable allows you to export your extension as a ready-to-submit ZIP file for your first submission.
What happens to my data? +
Your extension code runs in isolated sandboxes that are destroyed after your session. We store your source code on our servers. Your Anthropic API key and store credentials are securely stored in Supabase Vault.