How a non-coder built a $1M AI spreadsheet app in spare time

Executive overview

David Bressler built a viral AI tool for Excel and Google Sheets with no coding experience, using no-code platform Bubble.io and six weeks of paternity leave. He hit $5,000 in API costs within days of going viral — then rebuilt into a sustainable SaaS.

A no-code MVP, a viral Reddit post, and scrappy pivots can compound into 750,000 users and $26K MRR.

Building the MVP with no code

• David identified the problem from his day job: colleagues constantly asking for help with Excel formulas
• Chose Bubble.io as the only no-code tool he learned — well-documented and widely recommended
• Built the first version in a couple of weeks, entirely no-code
• Used YouTube tutorials to solve specific blockers rather than reading full documentation
• Worked evenings and coffee shops while managing a full-time senior role and a newborn

Getting the first users

• Told colleagues first — their reaction confirmed the idea had legs
• Posted to the Excel subreddit with a simple title: "AI Excel formula generator" — became top post of the day and week
• A commenter suggested posting to r/InternetIsBeautiful — that post hit 10,000 upvotes and drove thousands of users
• Initial traction was entirely free, organic, and happened within days of launch

Surviving the API bill crisis

• Open AI API costs hit $5,000 in days after going viral
• Recouped some costs via a donation link — made a few thousand dollars
• Ran a sponsored ad on an ESPN Excel esports broadcast for short-term revenue
• These stopgaps provided enough motivation to keep going rather than shut down
• Launched a paywall with subscriptions a few months later

Understanding what to build next

• Early product roadmap: "more generators" — VCs passed because there was no broader vision
• Shifted to talking directly with customers who emailed their actual Excel files
• Turned those emails into phone calls: solved their problem live, in exchange for product feedback
• Customer conversations drove expansion from a formula generator to a full data analytics platform
• The Data Analyzer product — natural language queries on uploaded data — became the most resource-intensive and differentiating feature

Competing against copycats and ChatGPT

• Within weeks of launch, ~10 copycat sites appeared with near-identical names and interfaces
• Early competitive advantage: convenience (no need to leave the spreadsheet) and multilingual customization
• Microsoft contacted David twice — second contact was to build a free Excel add-on, which he agreed to
• Realised Microsoft would absorb the core feature into their suite; pivoted to building features that can't be replicated there
• ~10% of churn attributed to ChatGPT; responded by adding features unavailable in ChatGPT
• Long-term strategy: build depth that neither ChatGPT nor Microsoft can replicate

Results at time of recording

• ~750,000 total users across 1.5 years
• ~5,000 paying subscribers
• ~$26,000 MRR
• App evolved from 100% no-code to ~5–10% custom code