The perfect stack will depend on the transaction volume, regulatory requirements and infrastructure. Common production fintech patterns: Java, Kotlin, or Go for high-throughput payment processing backends where performance and strong type systems minimise financial logic errors; React or React Native for cross-platform customer-facing interfaces; PostgreSQL or CockroachDB for transactional data with strong ACID guarantees; Kubernetes on AWS or GCP for cloud-native scalability. PCI DSS network segmentation and DORA resilience should influence infrastructure design as much as technology selection or engineering team experience.