Portfolio
Selected builds, systems, and tradeoffs. Raintree product pages live at raintree.technology.
Selected projects
17 projects
Agent Safety & Evals
Apps
Context & Developer Tools
Data & Intelligence Systems
Product SaaS
Systems & Low-Level
Music & Creative Systems
FlightSweeper
Travel SaaS / personal case study
Sweeps, booking, and encrypted PII
What I built
Live Duffel flight-search and booking workflow with month sweeps, Pro gates, and ticketing safeguards.
- live fares
- Duffel
- ticketing
- 2-phase
- PII encrypt
- AES-256-GCM
- prod guard
- RLS x14
Stack
- pnpm monorepo
- Next.js 16
- React 19
- Hono API
- Expo iOS path
- Duffel
- Stripe
- Drizzle + Neon
- Upstash Redis
Runtime
- Route Sweep calls live Duffel offers across month windows behind per-user sweep caps, global provider budgets, retry/backoff, and a serialized 900ms provider queue.
- Booking re-fetches the offer, creates a Duffel payment intent, verifies payment, issues the order, persists PNR, and refunds the payment intent if ticketing fails.
- Stripe handles Pro subscriptions only; Duffel Payments handles airline ticket payment through hosted payment UI so raw card data never touches the app server.
- Chat-to-book uses AI Gateway tools for live search, selection, passenger collection, payment handoff, and explicit confirmation instead of fabricated fares.
Data model
- Duffel offer requests, bookable offers, payment intents, orders, cancellations, fare snapshots, cost telemetry, and cached sweep results drive booking state.
- Users, sessions, saved routes, Stripe subscription state, referral events, chat transcripts, and AES-256-GCM encrypted passenger records live in Postgres.
- Airport, airline, destination, route, passenger, offer, sweep, mobile-session, and saved-route inputs are validated through shared schemas before provider calls.
Techniques
- Canonical Duffel wrapper centralizes SDK access, timeout/circuit-breaker behavior, offer TTL caching, re-pricing, order creation, refunds, and cost telemetry.
- Fare freshness carries `quotedAt` and `expiresAt`; stale offers return 410 before payment and booking confirmation runs against freshly validated offers.
- Postgres RLS plus explicit `userId` filters scope sweeps, orders, saved routes, offers, trips, and ownership failures as 404s.
- DOT 24-hour cancellation is authenticated, owner-scoped, unit-tested, idempotent, and reverses referral credit on cancellation/refund.
Verification
- AUDIT.md verifies Route Sweep, cheapest-month, booking, chat-to-book, and price-watch use live Duffel paths, while calling out partial discovery surfaces honestly.
- Production contract guard checks DB grants, 14 RLS policies, env vars, check constraints, and runtime DB role before accepting production state.
- Security tests cover schema contracts, HTTP behavior, Duffel webhook verification, cookie consent, chat logs, proxy, mobile auth, and production contracts.
- 4% service fee is capped at $9-$29 and drops to $0 for Pro; ticket payments stay with Duffel while Stripe only manages subscriptions.
- Passenger PII is encrypted at rest, cache keys avoid email where possible, and route errors log IDs rather than raw traveler data.