UCBOne Digital Superapp

UCBOne is the flagship digital banking and lifestyle application for United Commercial Bank PLC (UCB). Moving beyond generic banking applications, the platform is engineered as a highly resilient, polyglot microservices ecosystem designed to handle extreme concurrency, strict cryptographic security, and zero-downtime deployments.

As the Lead Software Engineer, I orchestrated the architecture of several mission-critical subsystems:

1. Polyglot Customer Identity & Access Management (CIAM)

The edge-facing authentication engine was built entirely in Golang (Echo/GORM) to handle thousands of concurrent authentication requests with sub-second latency.

• Hardware-Backed Biometrics: Implemented ECDSA-P256 cryptographic challenge-response mechanisms, ensuring private keys remain locked on the user’s mobile device.
• Anti-Replay Protections: Engineered strict timestamp window validations and Redis-backed nonces, completely eliminating session fixation and intercept-and-replay attacks.
• Stateful Profile Orchestration: While Go handles edge authentication, complex backoffice onboarding (KYC, Core Banking Sync) is orchestrated by a stateful Python (Django) engine utilizing Master-Replica CQRS database topologies.

2. Backend-Driven UI (BDUI) & App Registry

To enable dynamic feature rollouts without requiring App Store updates, I designed a high-throughput Configuration Engine that dictates the entire user experience via JSON schemas.

• Semantic Version Routing: Developed an advanced fallback algorithm that dynamically resolves the most appropriate API payload based on the client’s semantic versioning.
• Distributed Locking: Implemented Redis SETNX distributed locks. Under extreme load, this prevents “Cache Stampedes” by forcing concurrent requests into non-blocking spin-wait loops while a single worker queries the primary database.

3. Resilient Transaction Orchestration

Financial transactions require absolute consistency. The system utilizes Event-Driven principles to guarantee ledger integrity.

• Eventual Consistency via Polling: An autonomous background engine continuously resolves hanging transactions caused by upstream bank timeouts, utilizing exponential backoff retries.
• Circuit Breakers: Engineered custom Redis Circuit Breakers. During cache degradation, the circuit trips instantly, short-circuiting network calls and gracefully falling back to database computation or default values, preventing cascading cluster failures.