---
title: "I Will build a Chrome extension in JavaScript or TypeScript"
url: https://zinnhub.com/zinns/i-will-build-a-chrome-extension-in-javascript-or-typescript/
description: "A browser extension does one job well: a button that saves what you are looking at, a panel that pulls numbers off a page, a shortcut your team uses fifty times a day. I build those in JavaScript and TypeScript on Manifest V3."
published: 2026-09-29T10:35:05+00:00
modified: 2026-10-02T16:11:15+00:00
language: en-GB
---

# I Will build a Chrome extension in JavaScript or TypeScript

For teams whose daily work runs through web tools they can’t change, and who want those pages to do one more thing for them. Manifest V3 is the only format the Chrome Web Store accepts for new extensions, so every build starts on it.

You get the source in your own repository on every tier, and a build you load from a folder in developer mode on the first day after your brief, so you can click through it before anything is published. Starter covers one screen or action, Standard up to three with saved settings, Advanced up to five plus Firefox and Edge.

Typical jobs: a one-click form filler for a repetitive task, or a panel that talks to your own API. A screen that was not in the brief is new work: the add-on, or a new order.

I test on a clean profile and tell you which permissions it asks for and why. Advanced adds the Chrome Web Store listing: text, screenshots, privacy note, submitted from your own developer account, which stays yours.

Extensions that need someone else’s login, harvest personal data, or automate a service against its own rules are the ones I turn down, before the project rather than after. No calls; everything in writing.

Steps for completing your project
1. Scope confirmed in writing – I read your walkthrough and confirm the screens, the sites it runs on and the permissions it will ask for before any code. A panel that talks to your API counts as more than one action.
2. Dev-mode build on day one – The first screen or action working, loaded from a folder in developer mode, so you click through it on your own machine before anything else is built.
3. Remaining screens and settings – The rest of the screens, the settings page on Standard and Advanced, tests on a clean profile. A written update every working day on a multi-day build.
4. Permissions note, ports, listing – A note on every permission and why it is needed. On Advanced: Firefox and Edge ports tested, and the Web Store listing text, screenshots and privacy note ready to submit.
5. Handover in your repository – Source in your repository with a written handover: how to load it, how to build it, how to publish from your own developer account.