Personal details
Thomas H.
Technical skills
About
Senior full-stack engineer with 15+ years across IBM, Duke University, and early-stage startups. I specialize in taking ownership of existing production systems, improving their reliability, and making them economical to extend.
Most recently, I owned the backend of a social-events platform through growth from a few hundred to nearly 10,000 users, achieving 10× p50 and 7× p95 latency improvements on critical endpoints. I established automated testing and CI quality gates, built auditable database migration workflows, and implemented production monitoring and integration safeguards.
My experience spans TypeScript, Node.js, React/Next.js, PostgreSQL, Firebase, AWS, Terraform, and GitHub Actions, including SQL database recovery, tenant isolation, authentication, and security hardening.
I bring enterprise and institutional operational discipline from IBM and Duke, and pragmatic startup experience. My approach is to optimize for change: clear architecture, explicit boundaries, automated verification, and systems that remain safe and affordable to evolve.
Work Experience
- Built a multimodal AI study application supporting rich-media and document uploads, OpenAI-generated quizzes, and AI-graded responses with per-answer coaching (React, Vercel AI SDK, Vercel).
- Developed a multi-tenant Flutter/Firebase RAG application over government compliance documents and SOPs, with account-scoped authorization and isolated customer vector stores.
- Built OAuth 2.0 authorization flows, Stripe-backed paywall middleware, and OpenAPI-based API proxying for Custom GPT products as a reusable B2B SaaS prototype.
- Recovered a production Supabase/PostgreSQL system following a problematic schema change, using Supabase recovery tooling and
pg_dump. - Independently implemented Supabase/PostgreSQL multi-tenant security using RLS policies, least-privilege grants, scoped
SECURITY DEFINERfunctions, and tenant-safe relational constraints; added pgTAP and Playwright tests covering cross-tenant access, unauthorized writes, role permissions, and membership revocation. - Integrated Plaid into an SMS-based personal finance assistant for transaction tracking, spending queries, and account balances.
- Published a tourism marketplace to the iOS and Android app stores using React Native, AWS, and MongoDB.
- Sole full-time engineer responsible for an inherited production Node.js/Express/Firebase backend and Next.js administration tools during growth from a few hundred to nearly 10,000 users; delivered onboarding, payments, subscriptions, and event workflows.
- Modernized the API with TypeScript, modular architecture, and CI quality gates while delivering integrations with OpenAI, Stripe, Mailchimp, and Slack.
- Improved critical API endpoint latency by 10× p50 and 7× p95 through data-access optimization and architectural refactoring.
- Established Playwright API regression testing and Schemathesis fuzz testing in CI, validated against a live Firebase backend.
- Developed an auditable Firestore migration framework with version-controlled up/down migrations, execution records, and hash-verifiable CI rehearsal receipts.
- Implemented contextual Slack incident alerts using Firebase logging and Smartlook, along with operational kill switches for 10+ external integrations.
- Designed and operated AI-assisted delivery workflows, including reusable engineering skills, project knowledge, and structured issue/PR templates.