Pre launch / MVP
Word of mouth colleagues
Showed the MVP to colleagues at his full-time job. They were amazed it was built in just two weeks and validated that it solved a real pain point (helping people with Excel formulas).
→ First handful of users; strong early validation
Launch
Reddit organic post
Posted to r/excel with a simple title ('AI Excel Formula Generator') mentioning the tool was free and including only a link. No elaborate pitch.
→ Top post of the day, then top post of the week within the Excel subreddit
Viral spike
Reddit organic post
Cross-posted to r/InternetIsBeautiful after a commenter suggested it. The post received ~10,000 upvotes and thousands of comments, driving viral traffic for months.
→ Thousands of users in days; went viral for months
Post viral crisis
Donation link
After burning through ~$5,000 in OpenAI API costs in days, David put up a Stripe donation link explaining he was the solo builder and asking for optional contributions to keep the app alive.
→ Recouped a few thousand dollars; kept the product alive
Early monetization
Sponsorship ad deal
Ran a paid ad for the ESPN-affiliated extreme sports Excel competition ('esports for Excel'). The host reached out directly at peak virality; David designed the creative himself and ran it for ~1 week.
→ Drove a ton of clicks; modest revenue but motivated him to keep going
Month 3 4
Paywall subscription launch
Launched a proper paywall with logins and subscription tiers a few months after going viral, converting the free user base into paying customers.
→ First recurring revenue; ~5,000 paying users eventually
Product market fit expansion
Customer development calls
When users emailed Excel questions the tool couldn't answer and sent their actual files, David turned each request into a free 1-on-1 phone call — he'd do their work for them in exchange for product feedback and feature ideas. This directly shaped the roadmap beyond formula generation.
→ Roadmap evolved into a full data analytics platform; reduced churn drivers
Partnership / distribution
Microsoft addin store
Microsoft's add-ons team reached out and offered to build a Formula Bot add-in for the Excel add-on store for free. David accepted, gaining distribution inside Excel itself.
→ Listed in Microsoft's Excel add-on store; significant brand credibility boost
Scaling / moat building
Product expansion
Expanded from a single formula generator to three products: AI chat inside Excel/Google Sheets, formula generators, and a data analyzer (upload data → natural language queries → charts/analysis). Goal was to build features that ChatGPT and Microsoft couldn't replicate.
→ $26,000 MRR, 750,000 total users, 5,000 paying subscribers
MRR $26k Users 750k users