Fintech & Distributed Systems Engineer specializing in fault-tolerant payment orchestration, double-entry ledger architectures, and high-throughput asynchronous workers.
I design and maintain backend financial infrastructure where idempotency, strict auditability, and zero-data-loss recovery are non-negotiable.
- Payment Orchestration & Routing: Multi-PSP failover mechanisms, smart retry strategies, and client-side tokenization SDKs.
- Ledger & Reconciliation Systems: Immutable double-entry bookkeeping, automated settlement matching, and discrepancy alerting.
- Asynchronous Event Pipelines: Distributed background workers utilizing Redis Streams & message queues for webhook ingestion, fraud scoring, and automated refunds.
- Security & Compliance: PCI-DSS scope reduction, HMAC webhook verification, rate-limiting, and cryptographic payload signing.
| Domain | Technologies & Standards |
|---|---|
| Languages | TypeScript Node.js Go SQL |
| Data & State | PostgreSQL (ACID / Serializable Locking) Redis (Streams & Redlock) |
| Messaging | Apache Kafka RabbitMQ BullMQ |
| Infrastructure | Docker Kubernetes AWS (ECS, KMS, SQS) GitHub Actions |
| Standards | RESTful APIs gRPC OpenAPI 3.1 ISO 20022 Concepts Webhook Signatures |
| Project | Architecture Role | Core Stack |
|---|---|---|
| checkout-flow-sdk | Client-side checkout & tokenization SDK with multi-provider fallback | TypeScript Rollup WebCrypto |
| payout-gateway-service | High-throughput vendor payout engine & balance reconciliation API | TypeScript Node.js PostgreSQL |
| automated-refund-worker | Event-driven worker for idempotent refund pipelines & fraud audits | Node.js Redis BullMQ |
- Idempotency by Default: Every state-mutating request requires an
Idempotency-Keyenforced at the database constraint and distributed lock layer. - Event-Driven Decoupling: Critical payment paths respond synchronously only for authorization; settlement, notifications, and audit logs are processed asynchronously via durable queues.
- Graceful Degradation: External gateway timeouts trigger circuit breakers and automatic fallback routing rather than cascading system failures.
📫 Contact & Security Disclosures: lumillieju@hotmail.com