Hello, I'm
Oswaldo Rosales
Backend Software Engineer
Backend Software Engineer specializing in Java and Spring Boot. I build scalable APIs and microservices, modernize legacy systems, and lead distributed teams to deliver reliable, high-performance solutions.
With 9+ years of backend development experience, I specialize in Java and Spring Boot to build enterprise-grade microservices and REST APIs. I’ve worked on platforms across SEO, e-commerce, fintech, and healthcare. My focus is on writing clean, maintainable code and mentoring teams to improve engineering practices. I’m passionate about modernizing legacy systems and building scalable solutions that deliver real business value.
Work Experience
9+ years building enterprise applications and microservices architectures
Software Engineer (Independent Contractor)
Avenue Code
Software engineer contributing to large-scale SEO and AEO platforms, building and evolving systems responsible for dynamic sitemap generation, indexing workflows, and metadata management across high-traffic web properties.
Technologies:
Technical Lead
EPAM Systems
Led the modernization of a car rental listing platform within a large-scale travel ecosystem, improving system quality and enabling faster feature delivery through migration from legacy systems to a microservices-based architecture.
Technologies:
Technical Lead
UST
Led the development of a healthcare system focused on detecting Fraud, Waste & Abuse (FWA) in US insurance operations, used by hospitals and pharmacies to identify suspicious claims and reduce financial risk.
Technologies:
Full Stack Engineer & Team Co-Lead
IBM (Client Innovation Center)
Contributed to the modernization of core banking features, including a savings automation system and loan application flows, improving system reliability and scalability under growing customer demand.
Technologies:
Software Developer
SICAR Solutions
Contributed to a nationwide POS platform used by small and medium-sized businesses (retail stores, pharmacies, gyms, and hardware shops), helping them manage inventory, sales, and daily operations through a desktop-based solution.
Technologies:
Technical Skills
Comprehensive expertise across the full development stack
Languages
Frontend
Backend
Database
Infrastructure
Tools
Certifications
Architectural Thinking
IBM • November 2020
IBM Automation Essentials
IBM • June 2020
Banking Industry Jumpstart
IBM • December 2019
Featured Projects
A selection of my recent work and open-source contributions
Social Microservices Platform
Complete microservices architecture with gamification, multiplication service, and React UI
A comprehensive microservices learning project implementing Spring Boot best practices. Features include service discovery, API gateway, inter-service communication, and a React-based frontend. Based on 'Learn Microservices with Spring Boot' by Moises Macero.
oswaldorosalesdev.com
Personal portfolio built with Next.js 15, TypeScript, and Docker
Production-grade portfolio website with multi-stage Docker builds, SEO optimization, and self-hosted on Hetzner VPS. Demonstrates modern web development practices and infrastructure expertise.
Get In Touch
Have a project in mind? Let's talk about how I can help.
Available for US contracts via Speed of Bytes, Inc
US-registered corporation — I can invoice US companies directly in USD, provide a W-9, and engage as an independent contractor without administrative friction.
Available for Mexican contracts as an independent professional
Registered as a freelance professional in Mexico — I can issue valid invoices (CFDI) in MXN for Mexican companies and comply with SAT requirements.