PayTR Marketplace Solution
Architected and developed Turkey's leading marketplace payment solution as Lead Backend Developer for PayTR, a licensed electronic money and payment services institution regulated by the Central Bank of Turkey (TCMB). Built a comprehensive PCI DSS-compliant payment orchestration platform that enables e-commerce marketplaces to manage complex payment flows between buyers and multiple sub-vendors through a single integration. The system processes thousands of daily transactions worth millions in Turkish Lira, featuring automated commission management, real-time fraud monitoring, and intelligent payment routing. Integrated with Turkey's largest credit card brands and banking systems to provide installment payments, wire transfers, prepaid cards, and card-on-file storage solutions. Implemented Smart Catch technology for automatic vendor payment control and Smart Switch for seamless bank POS failover during outages.
Project Details
Key Features
- Single API integration supporting all payment methods: credit/debit cards, wire transfer, prepaid cards, mobile operator payments
- Real-time cash flow orchestration managing multi-party payment splits with automated vendor settlement
- Smart Catch: AI-powered vendor payment control preventing unauthorized fund transfers
- Smart Switch: Automatic failover routing across multiple bank POS systems ensuring 99.9% uptime
- Smart Secure: Intelligent 3D Secure routing optimizing conversion rates while maintaining security compliance
- Multi-basket checkout supporting purchases from different vendors in a single transaction
- Flexible commission engine supporting per-vendor rates, tiered pricing, and promotional discounts
- PCI DSS Level 1 compliant infrastructure with tokenized card storage
- Partial and full refund processing with automated vendor settlement reconciliation
- Real-time fraud detection using machine learning models and Central Bank integration
- Installment payment support across all major Turkish credit card brands
Challenges
- Designing fault-tolerant payment processing handling 100K+ daily transactions with zero data loss
- Managing complex multi-party settlement flows with atomic transaction guarantees across distributed systems
- Implementing PCI DSS compliance while maintaining sub-200ms API response times
- Building real-time fraud detection processing payment requests without adding latency
- Integrating with 15+ bank POS systems each with different APIs, protocols, and reliability profiles
- Ensuring ACID properties across payment, vendor settlement, and marketplace commission workflows
- Handling edge cases: network failures, partial settlements, concurrent refunds, and disputed transactions
- Meeting Central Bank of Turkey (TCMB) regulatory requirements for electronic money transactions
- Scaling horizontally while maintaining strong consistency for financial operations
Solutions
- Architected event-driven microservices using CQRS pattern with event sourcing for complete audit trails
- Implemented distributed saga pattern for managing multi-step payment workflows with compensating transactions
- Built high-performance payment gateway achieving 99.8% success rate and <150ms P95 latency
- Deployed Kubernetes cluster with horizontal pod autoscaling handling 10x traffic spikes during peak shopping periods
- Created Smart Switch system using circuit breaker pattern and weighted routing for intelligent POS failover
- Developed real-time fraud detection ML models processing transactions in <50ms using Redis and in-memory inference
- Implemented PostgreSQL with read replicas and Redis caching reducing database load by 70%
- Built idempotent API design with distributed locks preventing duplicate payment processing
- Designed flexible commission engine using rules engine pattern supporting complex marketplace business models
- Established comprehensive observability with Prometheus, Grafana, and distributed tracing achieving <5min MTTR
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