How to Build a Chrome Extension as a Solo Developer

What You're Building

A Chrome extension is a small program that runs inside the browser and modifies or enhances the browsing experience. Think ad blockers, password managers, productivity tools, or AI-powered assistants that sit in your toolbar. It's one of the best solo developer projects because distribution is built in through the Chrome Web Store, and the barrier to entry is surprisingly low.

I built my first Chrome extension in a weekend. It was a simple tool that modified a website I used daily, and it taught me that extensions are basically just web development with some extra APIs.

Difficulty & Timeline

Recommended Tech Stack

For the extension itself, use vanilla JavaScript or TypeScript. If you need a popup UI or options page, React or Svelte with a bundler like Vite works great. For the backend (if you need one), a simple API on Railway or Vercel handles user accounts and premium features.

Chrome's Manifest V3 is the current standard. Don't bother learning Manifest V2, it's being phased out.

Step-by-Step Plan

Phase 1: Foundation (Week 1)

Start with the Chrome extension boilerplate. Create your manifest.json, a basic popup, and a content script that does ONE thing. The Chrome Extensions documentation is actually quite good, so follow their getting started guide.

Load it as an unpacked extension in Chrome's developer mode. Get the core functionality working on your local machine before you think about anything else. I spent my first day just understanding how content scripts, background workers, and popups communicate with each other. Once that clicks, everything else is straightforward.

Phase 2: Core Features (Week 2)

Build out the main value proposition. If your extension modifies web pages, get the content script logic solid. If it's a productivity tool, nail the popup UI. If it needs to talk to an API, set up the backend and handle authentication.

Test on at least 5 different websites if your extension interacts with page content. I've been burned by extensions that worked perfectly on one site but broke on others because of different DOM structures or Content Security Policies.

Phase 3: Polish & Launch (Week 3)

Create promotional images for the Chrome Web Store listing (you need a 1280x800 screenshot and a 440x280 tile). Write a clear description that explains what the extension does in the first sentence. Set up a simple landing page.

Submit to the Chrome Web Store. Review usually takes 1-3 business days. While you wait, create a Firefox version (it's usually minimal changes with the WebExtensions API).

Monetization Strategy

Chrome extensions have several proven monetization models. The most common one for solo developers is freemium. Give away the core functionality for free and charge for premium features.

A one-time purchase of $5-15 works well for utility extensions. Subscriptions of $3-9/month work for extensions that provide ongoing value (like AI features that cost you API tokens). Use Stripe for payments and store license keys in your backend.

One approach I've seen work really well is offering a generous free tier that gets people hooked, then charging for power-user features. A thousand free users who tell their friends about your extension are worth more than fifty paid users who keep quiet.

Common Mistakes to Avoid

Requesting too many permissions. Users see a scary permissions dialog and bounce. Only request what you absolutely need. If your extension reads page content on specific sites, use host permissions for those sites only, not "all websites."

Ignoring Chrome Web Store SEO. Your listing title, description, and category matter. People search the store just like they search Google. Include relevant keywords naturally.

Not handling updates gracefully. Chrome auto-updates extensions, and if your update breaks something, users uninstall fast. Always test updates thoroughly before publishing.

Building a backend you don't need. Many extensions work entirely client-side. If you can store data in Chrome's local storage or sync storage, do that instead of building a server. Less infrastructure means less maintenance.

Is This Worth Building?

Absolutely. Chrome extensions have low development costs, built-in distribution through the Chrome Web Store, and can reach millions of users. Some of the most successful solo developer products are Chrome extensions. Detailed SEO Extension, Momentum, GoFullPage. These are small teams or individuals making serious revenue from browser extensions.

The market is also less competitive than web apps. While there are millions of SaaS products, there are far fewer quality Chrome extensions in most niches. Find a specific workflow that people do in their browser, make it faster or better, and you've got a viable product.

The one risk is platform dependency. Chrome can change their extension policies or APIs, and you're at their mercy. But that's true of any platform play, and the Chrome Web Store isn't going anywhere.