Backend & Fullstack Engineer

**Problem:** Needed a personal finance tracker capable of handling multiple accounts and concurrent requests without the thread contention issues common in sync ORM setups. **Decision:** Chose async SQLAlchemy 2.0 over the sync ORM — the async engine eliminates thread-per-request overhead, which matters for a financial app where multiple sessions may write simultaneously. Implemented MFA/TOTP (via pyotp) on top of JWT after identifying that token-only auth was insufficient for an app storing financial data. Chose bcrypt for password hashing over alternatives for its built-in work factor tuning. **Result:** Full-stack app deployed on Railway (backend) and Vercel (frontend) with sub-100ms API response times. Auth flow covers registration, login, JWT refresh, and TOTP enrollment/verification.

**Problem:** Needed a portfolio that itself serves as a technical signal — not just a list of projects, but a live demonstration of the stack I want to be hired to work with. **Decision:** Built a full backend (FastAPI + async SQLAlchemy + PostgreSQL on Neon) instead of a static site or headless CMS. This makes the repository itself evaluable code, not just a showcase. Chose next-intl for i18n to serve both English-speaking international recruiters (default) and Portuguese-speaking Brazilian market without duplicating routes. **Result:** Public repository at github.com/LucasAvilaa/portfolio demonstrates async Python backend, Pydantic v2 schemas, Alembic migrations, Docker, and Next.js App Router — all in production.