Open to opportunities

José David Colmán Cabral

@josdavidcolmncabral

Message

Senior Java developer crafting scalable microservices and high-performance REST APIs for fintech and e-commerce.

Paraguay

Message

What I'm looking for

I want to lead backend and API architecture for high-throughput systems—building event-driven microservices, improving reliability and latency, mentoring cross-functional teams, and delivering measurable business impact in fintech- or e-commerce-like environments.

I’m a Senior Java Developer with 11+ years designing and building scalable microservices and high-performance REST APIs. I focus on backend architecture that delivers reliability, measurable performance, and clean, maintainable code.

In my current role, I led a fraud detection platform using Java, Spring Boot, PostgreSQL, and object-oriented practices—cutting manual reviews by 65% while reducing customer friction by 30% and increasing digital revenue by 15%. I also architected a Kafka-backed digital wallet transaction platform in Java and Spring Boot, reaching 5,000+ TPS with sub-50ms latency and 99.99% reliability through eventual consistency.

I design secure, scalable solutions across AWS, including a serverless flow with AWS Lambda and API Gateway that reduced infrastructure costs by 40% and scaled automatically to 10K+ daily invocations. I’ve improved financial document storage with Amazon S3 (lowering storage costs by 25% and speeding retrieval by 60%), built a push notification service with Firebase Cloud Messaging and OAuth2 (90% delivery reliability, 35% lower SMS costs), and integrated an audit/logbook module into CI/CD pipelines for 50% higher audit efficiency and better compliance traceability.

Experience

Work history, roles, and key accomplishments

Current

Senior Software Engineer

Current

Bancard / Willdom

Jan 2024 - Present (2 years 6 months)

Led implementation of a fraud detection platform, cutting manual reviews 65% and increasing participating banks' digital revenue 15% while reducing customer friction 30%. Architected Kafka/Spring Boot Java microservices for a digital wallet processing 5,000+ TPS at sub-50ms latency with 99.99% reliability and built supporting AWS Lambda/S3/OAuth2 services.

Java Spring Boot Microservices PostgreSQL AWS Lambda REST APIs Kafka S3 OAuth

Senior Java Developer

Edge Mobile Ideas

Jan 2017 - Jan 2024 (7 years)

Built and maintained e-commerce microservices in Java/Spring Boot with Hibernate and PostgreSQL, deployed on AWS EC2, supporting 500K+ daily transactions and improving API response times 40% via CI/CD. Designed Apigee Edge API proxies with OAuth to cut latency 35% and improve security compliance 40%, plus optimized multimedia storage with S3+CDN.

Java Spring Boot Hibernate REST APIs PostgreSQL Apigee CI CD S3 EC2 OAuth

Mobile Developer

Palermo S.A.

Jan 2013 - Jan 2017 (4 years)

Developed Android sales applications using Java, REST APIs, and PostgreSQL, reducing order loading time 50% and improving back-office synchronization. Managed Windows Server, Linux, Active Directory, and networking for 200+ employees, achieving 99.9% uptime and reducing incident resolution time 40%.