Senior Software Engineer with 12+ years building scalable backend systems in Python and Java. Delivered a high-throughput API platform processing 5M+ daily transactions for a FinTech API provider, achieving 99.99% uptime. Combines deep expertise in cloud deployments, databases, and secure coding with a collaborative mindset to deliver reliable, secure applications.

Aleksandra Kwasniewska

Senior Software Engineer with 12+ years building scalable backend systems in Python and Java. Delivered a high-throughput API platform processing 5M+ daily transactions for a FinTech API provider, achieving 99.99% uptime. Combines deep expertise in cloud deployments, databases, and secure coding with a collaborative mindset to deliver reliable, secure applications.

Available to hire

Senior Software Engineer with 12+ years building scalable backend systems in Python and Java. Delivered a high-throughput API platform processing 5M+ daily transactions for a FinTech API provider, achieving 99.99% uptime.

Combines deep expertise in cloud deployments, databases, and secure coding with a collaborative mindset to deliver reliable, secure applications.

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Experience Level

Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert

Language

Javanese
Advanced

Work Experience

Senior Software Engineer at Bodare
November 1, 2022 - May 1, 2026
Senior Software Engineer at Pogo
September 1, 2020 - October 1, 2022
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.
Software Engineer at Plaid
March 1, 2017 - July 1, 2020
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.
Junior Software Engineer at Ravelin
October 1, 2014 - January 1, 2017
Built fraud scoring and merchant risk assessment capabilities, including real-time fraud scoring in Java Spring Boot. Developed REST APIs for merchant risk assessment and improved integration onboarding. Integrated machine learning model serving with Python and Flask, improved fraud detection accuracy, and created analytics dashboards with React/D3.js. Implemented synchronous alerting via Kafka to notify merchants of suspicious activity near real-time.

Education

Bachelor's Degree at University of Greenwich
October 1, 2010 - July 1, 2014

Qualifications

Add your qualifications or awards here.

Industry Experience

Financial Services, Healthcare, Software & Internet