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Yenfry Herrera Feliz

@yenfryherrerafeliz

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Senior backend engineer specializing in scalable Java and Spring transactional systems.

United States

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What I'm looking for

I’m looking to build and maintain high-reliability backend platforms, partner across engineering teams, and tackle production-critical distributed-system problems with strong observability and performance focus.

I’m a Senior Backend Software Engineer with 9+ years of experience designing, building, and supporting high-volume, transactional backend systems. I focus on reliable architectures and performance optimization, with a strong Java and Spring Boot foundation and hands-on experience across Spring MVC, Spring Security, REST APIs, SQL databases, and distributed systems.

Most recently, I served as the core maintainer of the official AWS SDK for PHP, a production-critical developer platform used across a large portion of the PHP/AWS ecosystem. I designed and shipped the S3 Transfer Manager for high-throughput multipart uploads/downloads—covering concurrent transfers, configurable concurrency, resumable operations, retry semantics, and progress tracking—while also implementing endpoint resolution using BDD graphs to replace brittle rule chains and improve lookup performance. I also partner across SDK teams (Java, JavaScript, Go, Python, Ruby, and PHP) to keep behavior consistent and improve reliability, performance, and developer experience.

Before that, I worked as a Developer Support Engineer on AWS SDKs for PHP, JavaScript, and Ruby, diagnosing complex distributed-system, networking, credential/authentication, and integration issues for enterprise customers. I built internal tooling for log triage and reproduction harnesses to reduce time-to-resolution, authored upstream fixes in official SDK repositories, and helped close the loop between customer issues and production code improvements—experiences that continue to shape how I approach root-cause diagnosis and delivery.

Experience

Work history, roles, and key accomplishments

Software Engineer

Amazon Web Services

Oct 2023 - May 2026 (2 years 7 months)

Core maintainer of the official AWS SDK for PHP and designed/shipped the S3 Transfer Manager for high-throughput multipart uploads/downloads, including concurrency, resumable operations, retry semantics, and progress tracking. Implemented endpoint resolution using BDD graphs and collaborated across SDK teams to align behavior and improve reliability and performance.

PHP AWS SDK for PHP S3 Multipart Uploads Concurrent Transfers Service Resumption Support Retry Progress Track BDD Endpoint Resolution

Developer Support Engineer

Amazon Web Services

Feb 2022 - Oct 2023 (1 year 8 months)

Supported AWS SDKs for PHP, JavaScript, and Ruby by diagnosing complex distributed-system, networking, and credential/authentication issues for enterprise customers. Built internal tooling for log triage and reproduction harnesses, and authored upstream fixes to improve official SDK repositories.

AWS SDK for PHP AWS SDK for Ruby Distributed Systems Networking Authentication and Credential Troubleshooting Upstream SDK Fixes

Software Support Specialist

DocuWare

Oct 2019 - Jan 2022 (2 years 3 months)

Led enterprise document-management migrations and database integrations involving Microsoft SQL Server (MSSQL) and Oracle environments. Wrote automation scripts to address recurring customer issues and improved deployment reliability by troubleshooting database, integration, and environment-level problems.

Microsoft SQL Server Oracle Database Database Integration Deployment Integrity Troubleshooting

Software Engineer (Contract)

Cloud Computing SRL

Jan 2018 - Jan 2022 (4 years)

Co-built and maintained Smart Lottery, implementing core transactional flows for betting, settlement, payouts, reporting, and reconciliation with an emphasis on correctness and operational reliability. Built backend services using Spring Boot, Spring Security, Spring AI, REST APIs, PostgreSQL, and MySQL, and delivered cross-platform clients using Flutter.

Spring Boot Spring Security Spring AI REST APIs PostgreSQL MySQL Flutter

Web Developer

INAFOCAM

Oct 2018 - Jul 2019 (9 months)

Built and maintained the national scholarship application platform for the Dominican Ministry of Education and maintained internal web systems and integrations supporting government education workflows.