Run it

Step 1 of 5 in the journey: purchase to a working extension loaded in Chrome, in about 10 minutes. No Firebase or Stripe account needed today: the extension runs sign-in-less out of the box, and the backend waits until steps 2 and 3.

Prerequisites: Chrome, Node 22, pnpm 8 (corepack enable picks up the pinned version), and git (the wizard uses it as a safety net).

1. Accept the GitHub invite

After purchase you get an invite to the private ExtensionStart repository on the GitHub account you provided. Accept it from the email or at github.com/notifications.

2. Clone and install

git clone <your ExtensionStart repo URL> my-extension
cd my-extension
pnpm install

pnpm install ends by running wxt prepare (type generation for the extension app). A warning-free install finishes on that step.

3. Run the setup wizard

pnpm create extstart

The wizard configures your clone in place. It downloads nothing. It refuses to run on a dirty git tree, so every change it makes is reviewable with git diff. You’ll be asked, in order:

1. Extension name and one-line description.
2. Scope: minimal, everything, or choose modules (the kit’s optional features) one by one. Keep everything for now; trimming later is easy.
3. Target browsers: chrome or chrome+firefox.
4. Monetization model and gate preset (if you kept billing/gates): accept the defaults.
5. The plan: review what it’s about to change, then “Apply this plan?”.
6. Env values: press Enter through all of them; nothing here is required today.
7. Firebase setup and backend doctor offers: answer No to both. You don’t have a backend yet.
8. Verify pass: regenerates WXT types and typechecks the pruned tree.

Every prompt is explained in the wizard guide. To skip the prompts, pnpm create extstart --yes --keep all accepts every default; see the CLI reference.

4. Start the dev build

pnpm dev

WXT builds the extension to apps/extension/.output/chrome-mv3 and watches for changes. It doesn’t open the browser; load it yourself in the next step.

5. Load it in Chrome

1. Open chrome://extensions.
2. Turn on Developer mode (top right).
3. Click Load unpacked and select apps/extension/.output/chrome-mv3.

6. Verify it runs

• The welcome tab opens by itself as soon as the extension loads.
• Pin the icon (puzzle-piece menu) and open the popup. You’ll see the “Connect your Firebase project” notice. That’s expected, since the kit ships placeholder Firebase config. Sign-in unlocks once you wire your own project in the Sign-in guide.
• If you kept content-demo: open any article page, select a sentence, and click the Highlight button that appears. That’s the content-script shadow UI working.

Your extension runs, with zero backend setup. Next, 2. Connect sign-in points it at your own Firebase project. Then 3. Take payments makes the upgrade button real.

The three most likely failures

1. The wizard exits with “Your git working tree has uncommitted changes.” It rewrites files and wants a clean baseline you can diff against. Commit or stash, then rerun (or pass --force).
2. Load unpacked can’t find the directory. .output/chrome-mv3 only exists after step 4 has finished its first build. Make sure pnpm ... dev is running and select apps/extension/.output/chrome-mv3, not apps/extension.
3. The popup opens but nothing responds. The background service worker crashed at startup. chrome://extensions → your extension → click the service worker link and read the error in that console. (Classic cause after manual edits: a chrome.* API used without its manifest permission; see How the background works.)