From Zero to $42K/Month in 90 Days with AI | Starter Story

In December 2024, CJ (Sajila Mazafer) launched Code Guide, an AI startup that helps developers write detailed documentation for AI coding models. Within 90 days, the business grew from zero to $42,000 in monthly recurring revenue without spending a dollar on paid marketing. The entire product was validated through a single tweet and built only after hundreds of users had already signed up for a waitlist. CJ’s story is a case study in how to find product-market fit by solving your own problem, validate before building, and grow through tutorial-based content.

The Idea Came from Solving a Personal Workflow Problem

CJ had been running an MVP agency where he spent nine to ten hours per project creating technical documentation that could be fed into AI coding tools like Cursor. He automated his own prompts into a sequence using Make.com, cutting that time to two hours. That internal tool became the seed of Code Guide. He built a landing page in 30 minutes using Bolt and shared his workflow in a tweet. The tweet went viral, generating 400 retweets and 300 sign-ups within hours. Within two weeks, he had 1,800 waitlist sign-ups. CJ did not write any product code until he had this evidence of demand. “Actual validation for me was when people started to sign up,” he says. He then DM’d every commenter to ask how they currently handled hallucinations in AI coding. Nobody had a better