(04) Systems
Systems & architecture
Projects built as bridges toward Data Engineering.
Multi-user personal finance platform: a layered Rust workspace (pure domain, SQLx data layer, Axum API, background worker) over PostgreSQL, serving an Expo app for iOS, Android and web plus a Tauri desktop shell.
Engineering decisions
- —Hexagonal crate split: an I/O-free domain checked in CI
- —Row-level security scoped on every pooled connection
- —Transactional outbox for push notifications, SKIP LOCKED job claims
- —Rotating refresh tokens, rate-limited login, typed error codes
- —Prometheus metrics, OTLP traces, health probes, graceful shutdown
- —Playwright E2E on the real stack, k6 load tests, compile-time checked SQL
Topology
Expo · Tauri
Mobile, web & desktop
Rust · Axum
Typed HTTP API, JWT
Rust · Tokio
Scheduled jobs
PostgreSQL 18
Triggers, RLS, analytics
Private source — walkthrough on request→Data bridge
Integrity enforced in the database: balances maintained only by triggers, row-level security per user, SQL analytics functions for trends and budgets, idempotent imports of third-party exports.