I built a SaaS with a Dual-Database Architecture (Transactional + Analytics) using Prisma & Neon 🚀

#showdev #webdev #architecture #saas

Hi everyone! 👋

I'm Olivier, a solo developer based in Spain.

For the past few months, I've been building Crono-Job, a workforce management platform. I wanted to share a bit about the technical journey and the architecture choices I made, specifically why I chose to split my data into two different databases.

🛠 The Stack

Frontend: React + Mantine UI (Absolutely love their hooks).
Backend: Node.js + Express.
ORM: Prisma.
Database: Postgres (hosted on Neon).
Infra: Render + Redis (for rate limiting).

🏗 The Challenge: Hot Data vs. Cold Logs

The app handles two very different types of traffic:

Critical Operations: Users clocking in/out, biometric photos from the Kiosk mode, and payroll calculations. This needs to be fast and consistent (ACID).
Analytics & Audit: Every click, page view, and system event is logged for the "Data Governance" module and audit trails.

I realized early on that if I dumped millions of analytics events into the same Postgres instance as the user data, my queries for the Dashboard would eventually crawl.

💡 The Solution: Dual-Database Architecture

I decided to implement a Dual-DB strategy within the same monorepo:

Main DB (DATABASE_URL): Stores Users, Shifts, Projects, and TimeEntries. It's optimized for transactional integrity.
Analytics DB (DATABASE_URL_ANALYTICS): A separate Postgres instance dedicated to AnalyticsEvent and logs. It's optimized for write-heavy operations (fire-and-forget).

Using Prisma, I manage two clients. One for the core app and a custom generated client for the analytics. This keeps my main DB crisp and responsive, no matter how much logging we do.

🚀 Launching the Public Beta

The project includes some cool features like:

Biometric Kiosk: Uses the webcam to capture evidence and verify identity.
Payroll Export: Generates complex Excel files compatible with Spanish payroll software (A3NOM).
Smart Policies: Geofencing and anti-fatigue blocks (12h rest rule).

I just launched the Public Beta (it's free right now).

If you are curious about the UI (Mantine in action) or want to stress-test my dual-db setup, feel free to check it out!

👉 Live Demo: https://crono-job.com

I'd love to hear your thoughts on this architecture. Is splitting databases overkill for an MVP, or a smart move for scaling?

Happy coding! 💻