Build an AI Chrome Extension · 20 min · WXT · Node.js · Chrome

Product Definition + Chrome Extension Architecture

A Chrome extension isn't one program -- it's 4 separate programs that can't call each other directly, and every confusing bug in this course traces back to forgetting that.

Hiring signal: Chrome extensions are one of the fastest, lowest-friction ways to put an AI tool in front of real users -- top AI extensions have millions of users, and understanding MV3's architecture is what lets you actually ship one instead of getting stuck on 'why can't my popup see my content script's data.'

What you will learn

Scope which 4 AI features this extension will ship, specifically enough to build
Understand Manifest V3's 4 contexts and why they can't call each other directly
Get a WXT project running in Chrome developer mode

Introduction

By the end of this course you'll have a real Chrome extension — an AI sidebar that works on any webpage — either live on the Chrome Web Store or packaged for someone else to install. Today, before any code: who is this for, and what exactly does it do?

Who is this for, specifically

"Anyone who wants AI on webpages" isn't a product decision, it's the absence of one. This course's reference product, Page Intelligence, is scoped for a specific person: someone who reads a lot of dense pages (articles, docs, product listings) and wants 4 concrete things without leaving the page — summarize it, ask it a question, pull out structured facts, or fact-check a claim. You'll rename and reshape this for your own angle, but pick a specific enough user that you can say no to feature ideas that don't serve them.

Ship the product shell before the AI works -- this is the whole point of Type D courses
The temptation is to get one AI feature working really well first, then "add the UI later." Don't. Lesson 2 builds a complete, navigable, professional-feeling UI with all 4 buttons visible and NONE of them wired to AI yet — because a rough AI feature inside a polished shell feels like a real product in progress; a working AI feature with no shell around it feels like a demo, even when the underlying capability is identical.

Unlock the full lesson

You've read the first 2 sections. The rest of this lesson covers The 4 contexts, and why they can't just call each other, What You're Building — plus a hands-on lab, quiz, and project artifact.

Create a free account to unlock Phase 0 and Phase 1 of every course — no credit card.