School covers personal finance for one semester and most kids forget it by graduation. I wanted something that stays useful — lessons you can come back to when you actually need them. So I built Finly.

What it is:

90+ lessons on budgeting, credit, taxes, investing, and finance careers. Stock portfolio simulator using real S&P 500 historical data. Classes system for parents and teachers. No ads, no paywall, ever. Incorporated as a nonprofit.

The stack:

Next.js, Supabase, Vercel, TypeScript.

The hardest parts

• Downloaded 3 years of daily price data for 503 S&P 500 tickers using yfinance, migrated it to Supabase, built a portfolio simulator that replays history week by week with market events

• COPPA compliance for under-13 users

• Getting two age tiers (8-12 and 13-17) to feel genuinely different, not just simplified

Where I used AI : I used Claude Code for most of the implementation. The lesson content was based on notes I took from my personal finance class and I used AI to flesh those out into full lessons.

learnfinly.com — free, no ads, no paywall ever.