SAO Psychotherapy

About the project

Clinical management web platform for a real psychology clinic in Barcelona with multiple therapists. I joined a production project with real payments. Discovered 4 critical financial bugs in Stripe Connect causing losses of +€1,400 without anyone knowing, documented with cent-level precision. Fixed critical issues in the billing system, migration to destination charges, anti-duplicates in automatic payments and webhook stabilization.

Technologies

Features

• Financial audit: 4 critical bugs detected, +€1,400 in errors documented
• Stripe Connect bug fixes: migration to destination charges, 4-level anti-duplicates
• Atomic webhook stabilization and automatic billing system fixes
• Complete traceability of every euro to Stripe transaction ID
• Multi-system diagnosis and fixes (PostgreSQL + Stripe API + cron jobs + webhooks)

Technical challenges

• Joining production codebase with real money without breaking anything
• Diagnosing multi-system financial bugs (PostgreSQL + Stripe API + cron jobs + webhooks)
• Complete traceability of every euro to Stripe transaction ID
• Migration to destination charges without interrupting production service
• Implementing 4-level anti-duplicates for automatic charges

Learnings

• Technical financial auditing in real payment systems
• Advanced Stripe Connect: destination charges, idempotency, atomic webhooks
• Working with real money in production — zero tolerance for errors
• Forensic documentation of bugs with economic impact
• Full-stack development in regulated clinical environment