I shipped my first SaaS in a day — here's the stack, the costs, and what I learned

I've been in analytics and business strategy for 13 years. I know Python. I understand data. I've made a career out of helping companies make smarter decisions. But until last week, I'd never built anything for myself. Every side project got stuck in planning mode — researching, overthinking, waiting for the perfect moment that never came. Last week I tried something different. No planning. No Notion docs. Just sit down and build. What I built A CSV analyzer. You upload a CSV file and it instantly gives you: Column-level statistics (mean, median, std dev, unique values) Interactive charts (histogram, scatter, bar with percentages) AI-powered analysis that explains your data in plain English Everything runs in the browser. Your data never gets uploaded to a server. The AI analysis sends only summary statistics to the backend, not your raw data. The stack Next.js — frontend and API routes Anthropic API (Claude) — powers the AI analysis Stripe — payment processing Vercel — hosting (free t