Finsava / Infrastructure
Your money. Your intelligence. Your rules.
How We Run a Full-Stack Fintech App for $7/Month
Published March 2026 · 5 min read
Finsava is a personal finance app with AI-powered categorization, bank sync from 12,000+ institutions, Monte Carlo retirement simulations, interactive budget charts, and a health score engine. Our entire infrastructure costs $7/month.
Here's how we do it.
The Stack
- Backend: FastAPI (Python 3.11) with async SQLAlchemy
- Frontend: Next.js 15 with React 19
- Database: PostgreSQL 16
- Reverse Proxy: Caddy (auto-HTTPS, security headers)
- AI: Claude API (Anthropic) for categorization + Ollama for local inference
- Bank Sync: Plaid + SimpleFin
- Deployment: Docker Compose
Everything runs in a single docker-compose.yml. No Kubernetes, no managed services, no multi-region complexity.
The Host: Hetzner CX33 ($7/month)
We chose Hetzner Cloud after evaluating 9 hosting options. For $7/month (EUR 6.49), we get:
- 4 vCPUs
- 8 GB RAM
- 80 GB NVMe SSD
- 20 TB transfer
That's enough to run the entire stack with headroom. PostgreSQL, FastAPI, Next.js, and Caddy all run comfortably within 8 GB.
Why Not Railway / Render / Fly.io?
We evaluated managed platforms extensively. The problem: they don't support Docker Compose natively. Each service gets deployed separately, which means vendor-specific configuration and reduced portability. Our Docker Compose file works on any VPS, anywhere. Zero lock-in.
| Platform | Monthly Cost | Docker Compose | Portability |
|---|---|---|---|
| Hetzner + Coolify | $7 | Native | 10/10 |
| DigitalOcean | $12-24 | Native (VPS) | 9/10 |
| Railway | $5-12 | Partial | 6/10 |
| Render | $20+ | No | 5/10 |
| Fly.io | $10-12 | No | 5/10 |
The Deployment Layer: Coolify
Coolify is a free, open-source PaaS you install on any VPS. It gives us a web dashboard for deployments, auto-SSL, git-push deploys, and monitoring — essentially a self-hosted Railway. The software is free; we only pay for the VPS.
AI Without Breaking the Bank
Claude AI (Anthropic) handles transaction categorization. We keep costs near-zero with a merchant-to-category cache: once a merchant has been categorized the same way 3 times, the result is cached and reused without an API call. For recurring merchants (70-80% of transactions), the cache eliminates redundant API calls entirely.
The Portability Guarantee
Docker Compose is our insurance policy. If Hetzner raises prices, if we outgrow 8 GB, or if we need US-based hosting — we move the same docker-compose.yml to any other provider. No rewrite, no migration, no vendor lock-in.
What This Means for Users
Our infrastructure cost is $7/month. Finsava Basic is $4.99/month. The math is simple: we can offer a genuinely full-featured finance app at a fraction of the price of YNAB ($14.99) or Monarch ($9.99) because our cost structure allows it.
We're not a venture-funded company burning through runway. We're building a sustainable tool for people who care about where their money goes — and we practice what we preach.