From zero to $40K/month with a one-feature website

Angus Chang built a website that does exactly one thing: convert bank statement PDFs into Excel spreadsheets. That single function now generates $40,000 per month in revenue, and he runs the entire operation alone. No employees, no co-founder, no outside funding. The business emerged not from market research or a grand strategy, but from a personal frustration: after quitting his job, he wanted to consolidate years of bank data into one spreadsheet to figure out how long his savings would last, only to discover that extracting transaction data from PDF statements was surprisingly difficult.

Finding the idea and building the MVP

Chang encountered the problem himself, which became his primary filter for identifying opportunities. Rather than searching for market gaps or running validation surveys, he paid attention to his own pain points and the complaints of colleagues. When he wrote code to extract his own bank statement data, the difficulty of the process suggested others might face the same problem. He and a friend built an MVP in about one week — a Kotlin backend for PDF parsing paired with a Next.js frontend — and immediately started buying Google search ads. People uploaded bank statements right away, which confirmed the problem was real.