Implemented and validated more than 20 REST APIs in PHP/Laravel for an e-commerce platform with 200,000+ monthly users, using Postman for functional and integration testing. Tested integrations with payment gateways (Stripe, Authorize.net, Plaid), validating transactional flows, error handling, and edge cases in checkout processes. Implemented unit and integration tests to ensure system stability during continuous deployments. Optimized performance across 4 websites, identifying bottlenecks and improving load metrics. Utilized Redis for caching and sessions on a high-traffic platform; monitored behavior under load.

SCRUM Master for a team of 3 people (2 developers and 1 QA), coordinating sprints and quality criteria. Designed and implemented RESTful and SOAP services with end-to-end validation of integrations.

Developed backend in Java EE with integration of RESTful and SOAP services; validated services with Postman. Implemented stored procedures in Oracle PL/SQL and optimized critical queries. Collaborated with QA to define acceptance criteria and resolve defects in testing cycles.

Designed and executed manual and automated test cases for mission-critical systems. Defined test strategies, acceptance criteria, and regression plans for production releases. Executed performance and load tests, identifying bottlenecks and high-impact defects. Reported, documented, and followed up on incidents in coordination with the development team.