Building a $20K/month Chrome extension as a solo developer

Executive overview

Most developers think building a product means competing with the entire internet. Building inside an existing platform marketplace narrows the field and makes validation faster.

Saeed Ezzati launched a ChatGPT browser extension within days of ChatGPT's release, grew it to 150K weekly active users, and reached $20–30K MRR — solo, with zero paid marketing.

The edge isn't technical sophistication — it's timing, listening to users, and shipping inside a marketplace where distribution already exists.

Choosing where to build

• Target platforms with large existing userbases: Gmail, YouTube, Twitter, Roblox.
• Alternative: smaller platforms with a marketplace (Zoom, Salesforce) — fewer competitors, still discoverable.
• A marketplace beats a standalone SaaS for early validation: faster to build, easier to rank, smaller competitive pool.
• Even capturing 2,000 users from a platform with hundreds of millions is enough for meaningful revenue.

Finding ideas worth building

• Build for your own frustrations first — Saeed's initial features were things he personally wanted in ChatGPT.
• Go where potential users gather: subreddits, Discord servers, Slack groups, Facebook groups.
• Listen for repeated feature requests, then build the requested feature and tell that community it's done.
• Look at professional niches where AI is underused — doctors, lawyers — and learn how they actually use AI day-to-day.

Building quickly with minimal stack

• Chrome extensions only need JavaScript, HTML, and CSS — the same skills as a basic website.
• Saeed went from zero extension experience to launched product in two to three days.
• He stripped out frameworks and used plain JavaScript for speed and simplicity.
• Backend on AWS; newsletter on Beehive (with its built-in monetisation via Boost links).

Growing without paid marketing

• First post on a relevant subreddit reached the top of that community for the day.
• No ads, no paid articles, no sponsored content — all organic.
• Tech writers and YouTubers naturally included the extension in "best ChatGPT extensions" roundups.
• Product quality drove word-of-mouth; users shared it because it solved a real problem.

Monetisation sequence

• Extension was free for the first nine to ten months to maximise user growth and capture an audience.
• A newsletter launched a few months in; within one to two weeks, Saeed had a paying sponsor.
• Newsletter writing dropped from six to seven hours per issue to roughly two hours as the process matured.
• Monetised the extension by adding new paid features — all existing free features stayed free.
• Experimented with pricing tiers to find the right balance.
• PassionFruit used to connect with newsletter sponsors.

Platform risk and how to think about it

• Building on top of ChatGPT means OpenAI could replicate or block the extension at any time.
• Saeed's view: accept the risk, stay numb to it, and be prepared to pivot to another platform if needed.
• Being early matters more than being safe — waiting for certainty means missing the window.

Key advice for getting started

• Validate as fast as possible: ship the first version and see if anyone uses it.
• Play to your strengths — for Saeed that meant building and sharing for free to get early users.
• Don't wait for a perfect idea; timing and speed of execution matter more than originality.