Aleksandra Kwasniewska

Built and maintained backend services and distributed systems supporting high-volume fintech and healthcare workflows. Implemented and optimized microservices for claims processing, claims adjudication, billing, and real-time event handling. Developed serverless data ingestion pipelines on AWS Lambda with Python, built multi-tenant SaaS billing with role-based access control and Stripe integration, and migrated monolithic systems to AWS microservices reducing deployment downtime. Improved performance by redesigning caching layers using Redis and optimizing data pipelines with Kafka and Python. Strengthened security through automated SAST/DAST-like security scanning in CI/CD, implemented TLS and API key rotation, and containerized services with Docker and Kubernetes to improve deployment consistency and reduce release cycle time.

Delivered healthcare portal capabilities using Java and React with FHIR integration across 50+ hospital systems, improving data accessibility. Built a claims adjudication microservice in Python, reducing processing errors by 35%. Developed real-time analytics and fraud-related services, including webhook notification systems and API services handling millions of requests per day. Engineered reliability and performance improvements through caching with Redis and asynchronous event processing using Kafka. Contributed to cross-functional delivery, mentorship, CI/CD automation with Docker/Kubernetes, and secure coding practices.