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Andrii Korenev

@andriikorenev

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Senior Backend Developer at Chess.com who cut MySQL query response time by up to 30x and built Symfony microservices.

Germany

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What I'm looking for

I’m interested in high-load e-commerce and large-scale SaaS platforms, where I can develop backend systems and work on performance, scalability, and database optimization.

At Chess.com, I refactored monolithic backend modules into Symfony microservices and designed internal REST APIs using Protocol Buffers. I also tuned high-frequency MySQL queries and indexes, reducing query response time by up to 30x.

As a freelance PHP developer, I built an Amazon and Walmart data analysis platform that reduced processing time by 80% for 20M+ records. I’ve also developed web applications and CRM systems using PHP, Symfony, Laravel, MySQL, and PostgreSQL.

Experience

Work history, roles, and key accomplishments

Senior Backend Developer

Chess.com

Feb 2021 - Jun 2026 (5 years 4 months)

High-load backend development for the world's leading online chess platform (10M+ DAU, 100M+ daily events). Refactored monolithic modules into microservices, optimized MySQL queries achieving up to 30x reduction in response time, and built automated SEO pipelines and dynamic image generation services.

PHP 8+Symfony MySQL Redis Protocol Buffers Datadog Sentry GitHub REST APIs Microservices CI CD Query Optimization Indexing PHP GD Intervention Image Cron Background Workers

Freelance Full-Stack / Backend PHP Developer

Upwork / Self-Employed

Dec 2010 - Feb 2021 (10 years 2 months)

Delivered scalable web solutions, platforms, and analytics systems for international clients using PHP, Symfony, Laravel, MySQL, and PostgreSQL. Built a product analysis platform for Amazon/Walmart data, an aviation maintenance CRM, and various web applications.

PHP Symfony Laravel MySQL PostgreSQL Redis AWS SQS Python WordPress Drupal CodeIgniter REST APIs Data Analysis CRM Development

PHP Developer

Behind the Ocean

Sep 2010 - Dec 2010 (3 months)

Developed web applications using CodeIgniter, customizing CMS solutions and writing performant backend code under tight deadlines.

PHP CodeIgniter CMS Backend Development

Support Specialist -> PHP Developer

Conkurent, LLC

Feb 2010 - Sep 2010 (7 months)

Promoted from support specialist to developer. Developed a PHP Forms platform for visual form creation and contributed to internal CRM development.

PHP CRM Web Development

Head of Sales Department

Foxtrot

Jun 2006 - Oct 2009 (3 years 4 months)

Led a sales department, developing strong cross-functional communication, team management, and client consultation skills.

Team Management Sales Client Consultation Communication Skills

Junior C++ Developer

VIT

May 2005 - May 2006 (1 year)

Developed people recognition algorithms in C++ for video surveillance systems, focusing on real-time data processing and performance.

C++Real time Data Processing Algorithm Development Video Surveillance

Education

Degrees, certifications, and relevant coursework

Zaporizhzhia National Technical University (ZNTU)

Master's Degree, Specialized Computer Systems

2001 - 2006

Master's Degree in Computer Engineering from Zaporizhzhia National Technical University, specializing in specialized computer systems with a focus on software development, hardware-software integration, and system architecture.