Browser Extension Builder

Pick a template, fill in your details, and download a complete browser extension — Manifest V3, a popup, a settings page, a background worker, the store paperwork and a README that walks you through every step. Chrome, Firefox or Safari. No build step and no dependencies: the files in the folder are the files that run.

Choose a template

Loading the templates…

How it works

Three steps, then it is running in your browser.

Pick and fill in

Every field is on one page — name, description, colours, which sites it may run on, and whatever that template needs. The name and description are checked against the store's own character limits as you type.

Download the folder

manifest.json, background.js, popup/, options/, lib/, real PNG icons, PRIVACY.md generated from the permissions it actually requests, and a README written from the template's own declarations.

Load unpacked

chrome://extensions → Developer mode → Load unpacked. No npm install, no bundler, no build step. When you are ready to publish, npm run pack writes the store zip.

✦

What is in every template

Written for the platform, not against it

Manifest V3, the only version either store still accepts
One codebase for Chrome, Edge, Brave, Opera, Firefox and Safari
Periodic work uses chrome.alarms — a setInterval in a service worker stops when the browser stops it, which is soon and silent
Nothing is kept in a variable between events; state lives in storage
No import anywhere: Chrome runs the background as a service worker and Firefox as an event page, and one classic script is the only shape that is correct in both

Security that is actually there

Content scripts never put page data into innerHTML
Their UI lives in a closed shadow root — the page cannot restyle it away, and it cannot break the page
An explicit script-src 'self' policy, so an accidental CDN script fails at load rather than in review three days later
Match patterns are validated before they ship: one malformed entry and Chrome refuses the whole extension
The permission list is the minimum each template uses — an unused permission is the most common reason a review comes back

✦

The paperwork, generated

Chrome will not publish an extension that requests any permission without a privacy policy, and a reviewer reads it against the manifest. So it is not written by hand here — it is generated from the permission list this build actually requests, which means it cannot claim less than the extension asks for.

PRIVACY.md — every permission, and one sentence on why
store/listing.md — the copy for both dashboards, with the character limits counted for you and a pre-submission checklist
scripts/pack.mjs — a store-ready zip with the files at the top level, which is what both stores require and neither error message says
LICENSE.md — it is yours: publish it, charge for it, keep the money, including after the subscription ends

✦

What it costs to publish

Chrome Web Store — $5 once, ever. Review takes a few days, longer if you ask for <all_urls>
Firefox Add-ons — free. Usually under a day. Signing is free even for an add-on you never list publicly
Safari — $99/year, and it is an App Store review of a real Mac app. Running it on your own Mac costs nothing

None of that is paid to us and none of it is required to use what you build — an unpacked folder runs in Chrome and Firefox for as long as you like.