DataForge

I built the first version to study for the Google Cloud Professional Data Engineer exam, which I passed. Once it worked for me, the interesting question became whether it could work for other people too, so I turned it into a product.

A React app with a static landing, sign-in through Supabase (Google, GitHub, email or magic link), progress synced across devices, and a 20-question trial that needs no account. It covers practice and block-by-block study, timed mocks weighted like the real exam, a daily challenge, and a gamification layer with XP, ranks, achievements, and boss battles.

• A cert-agnostic engine: each certification is a folder with its manifest, domains, and question bank, so adding one doesn't touch the app.
• localStorage is the cache the app reads from. Every key is mirrored to Supabase (debounced, with row-level security per user), and unconfirmed writes are pushed on the next visit.
• Views only present and emit. State lives in hooks and a pure engine covered by Vitest, and question banks ship as lazy-loaded chunks.
• Deploys to Vercel on every push, and also runs fully local or in Docker behind nginx.

• Two Google Cloud certifications live (Professional Data Engineer and Professional Cloud Architect) with 600+ practice questions.
• Used for my own successful PDE exam attempt.
• Public landing, legal pages, and a trial mode that works without signing up.

More certifications, and a pipeline that generates and validates questions from official documentation, with human review of anything flagged.

• React
• Vite
• Supabase
• PostgreSQL
• Vitest
• Vercel
• Docker