Completed
Public personal project
2026
Expenser: Full-Stack Expense Manager & Self-Hosted Infrastructure
A multi-currency finance application and self-hosted micro-cloud project demonstrating API quality, data integrity, security, and end-to-end systems thinking.
Architected Expenser, a NestJS and PostgreSQL personal finance API, and deployed it on a custom Fedora Linux mini PC. The project combines financial calculation and persistence concerns with a security-focused self-hosted environment managed through Docker and Coolify.
TypeScriptNestJSPostgreSQLPrismaDockerCoolifyCloudflare TunnelsTailscaleFedora Linux
Key Highlights:
- Multi-currency budget aggregation with cached exchange rates
- Token authentication, strict CORS, Helmet, and payload limits
- Zero-trust public ingress through Cloudflare Tunnels and private Tailscale access
Tools & Technologies
Challenges
- Keeping multi-currency calculations and relational data consistent
- Exposing services publicly without opening router ports
- Resolving Tailscale and Traefik interface and port conflicts
Solutions
- Used Prisma constraints, upserts, and nullable cascading relations to protect data integrity
- Added timing-safe token authentication, strict CORS, Helmet, and request limits
- Separated public Cloudflare Tunnel ingress from private Tailscale administration and fixed interface bindings
Results
- Delivered a working full-stack finance application with resilient exchange-rate synchronization
- Created a reproducible Docker and Coolify deployment on personal hardware
- Demonstrates QA-relevant API, integration, security, failure-handling, and release-validation thinking