B.E.S.D. FINANCEHUB

BESD Finance Hub is a consumer fintech app on the App Store that puts a person's whole money picture in one place: linked bank accounts, credit score and report, debts, bills, subscriptions, home and vehicle value, goals and cash flow. On top of that sits Hey-B, an AI advisor that answers questions about your own finances using your real data. I was the sole engineer on the build, from the backend to the iOS app, writing 1,012 of the 1,121 commits.

Hey-B is a tool-calling agent built on Mastra. It has 12 Zod-typed read-only tools that run structured SQL against Postgres and return precomputed totals, so the model never does arithmetic. Conversation memory lives in Postgres. Uploaded statements are chunked into pgvector and answers cite the chunk they came from. A golden set of about 50 questions runs on every deploy and scores the answers, so a prompt or model change that makes Hey-B worse fails before it ships. It started on Groq and OpenRouter and now runs on Amazon Bedrock.

Every tool call is bound to the user's JWT, gated by consent and plan, and reads from redacted views where account numbers and identifiers are masked and the numbers are already summed. A test suite scans every view for leaked ids. Secrets stay backend-only, and auth uses short-lived JWTs with refresh-token revocation.

I rebuilt the backend from scratch on Express 5 and Prisma: 24 models, 121 routes, 176 tests against a real Postgres. Plaid handles bank linking, Array provides credit reports and identity monitoring, Stripe runs subscriptions, and sign-in is OTP based. The iOS app is React Native, shipped to the App Store on a production backend.

React Native, TypeScript, Express 5, Prisma, PostgreSQL, pgvector, Mastra, Amazon Bedrock, Plaid, Array, Stripe, AWS.