Things I've built

Next.js App Router on Supabase Postgres, with row-level security layered down to individual billing columns and a PBKDF2-hashed parental PIN gating the dashboard. Curriculum is data, not code — packs → topics → questions, each question rendered by one of 60+ interactive presenter components instead of static images, so new subjects drop in without engine changes. A pure, unit-tested SM-2 spaced-repetition engine assembles each day's session; Stripe card-less trials reconcile via webhook plus a daily cron sweep, and question difficulty recalibrates nightly from real answer stats.

A single authoritative Node.js server holds all room and race state in memory and drives an event-driven WebSocket protocol. Timing is measured server-side and client-reported times are clamped against the server's own clock, so the leaderboard can't be cheated. The dependency-free vanilla-JS client animates purely with DOM and CSS transitions — no framework, no build step. Hardened with a strict no-inline CSP, per-IP connection and message-rate caps, and graceful-shutdown persistence to a volume-backed leaderboard. Gameplay details stay under wraps — the client's call.

Next.js Server Components with server-only content loading — exam blueprints are typed TypeScript, questions and flashcards are JSON, study guides are markdown. Correct answers are stripped from every client payload and all grading runs in Server Actions, so answers never reach the browser. Mock exams sample across domains by official blueprint weights against a server-authoritative deadline with autosave; flashcards run a custom SM-2 scheduler persisted per user in Supabase, where the database stores only user progress — content ships with the app — and row-level security keeps every row private.

A two-stage cron pipeline, each stage inside its own serverless time budget: the fetch stage pulls futures, weather, freight, COT, and USDA data plus news across 15 lanes and stages it all to Postgres; the publish stage runs a three-tier Claude chain — Sonnet triages headlines into corroborated claims, Opus analyses under explicit validity rules (and may request up to three follow-up searches), Sonnet edits the prose but is barred from changing numbers. Charts are Chart.js configs generated deterministically from the data, shared identically by web and email; every directional call is stored with its baseline price and graded mechanically at maturity for a public track record. The final production version is in progress for the client.

A lean Next.js App Router site composed from section components, styled with a Tailwind v4 design-token system, with Open Graph cards generated at the edge. The enquiry flow is a single API route into Resend — validated, HTML-escaped, and honeypot-protected against bots — and scroll-reveal animations run on a tiny IntersectionObserver with a no-JS fallback.

Zero-framework static HTML and CSS — no build step, no dependencies. Inline SVG icons, responsive image variants, and click-to-play YouTube embeds that load nothing until tapped. Built entirely in conversation with Claude Code and deployed to Vercel straight from the terminal.