Volodymyr Kolesnykov
Senior Software Engineer at Automattic
Ukraine
Summary
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Rockstar🎓
Top SchoolVolodymyr Kolesnykov is a Senior Software Engineer based in Ukraine with over 15 years of hands-on professional experience and a personal history of building high-performance server and web applications for 20+ years. He brings deep expertise in PHP internals and C/C++—contributing to prominent open-source projects like the Phalcon framework and php-cpp—focusing on memory management, exception handling, and thread-safety fixes that materially improve stability and performance. At Automattic and Netguru he’s delivered and modernized large PHP codebases, led migrations (Symfony/Laminas), and enforced high static-analysis and security standards across services. His background spans full-stack web, DevOps, and mail infrastructure (PowerMTA, Postfix/Dovecot) with practical experience mitigating DDoS and running resilient server fleets for volunteer and commercial projects. Volodymyr pairs low-level systems craftsmanship (C/C++ extensions, Zephir) with Cloud/Container workflows and CI tooling, making him effective at both optimization and operational reliability. An unusual strength is his long record of fixing subtle, hard-to-reproduce bugs in language bindings and extensions—work that quietly prevents outages at scale.
15 years of coding experience
16 years of employment as a software developer
Bachelor's degree, Computer Science, Bachelor's degree, Computer Science at Sevastopol National Technical University
Russian, English, Ukrainian, Russian
Stackoverflow
277reputation
17kreached
1answer
0questions
Github Skills (27)
url-routing10
debug10
maintenance10
c-language10
qt10
back-end-development10
testing10
memory-management10
object-oriented-programming10
smtp10
c1110
smtps10
c1710
smtpd10
php10
Programming languages (12)
Github contributions (5)
phalcon/cphalcon
Jun 2013 - Apr 2017
High performance, full-stack PHP framework delivered as a C extension.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1656 commits, 99 PRs, 14 pushes in 3 years 10 months
Contributions summary:Volodymyr contributed significantly to the development and maintenance of the Phalcon framework, with a focus on back-end improvements. Their work included bug fixes, specifically addressing issues related to exception handling, memory leaks, and correct implementation of the framework's features such as the `Phalcon\Mvc\Model` and other related modules. The user's code changes demonstrate improvements to the code's efficiency and robustness. The user also worked on the implementation of the PSR-3 classes.
full-stackphpframeworkphalconphp-extension
zephir-lang/zephir
Sep 2013 - Aug 2017
Zephir is a compiled high-level language aimed to ease the creation of C-extensions for PHP
Role in this project:Backend Developer
Backend DeveloperContributions:195 commits, 109 PRs, 47 pushes in 3 years 11 months
Contributions summary:Volodymyr primarily contributed to the Zephir language's core functionality by addressing code issues and implementing necessary changes for PHP extensions. Their commits included refactoring to incorporate `TSRMLS_CC` into function calls and adapting the code to utilize `SEPARATE_ZVAL_IF_NOT_REF`. The user also made critical adjustments regarding memory management, including fixes to memory leaks and optimized code generation for various PHP versions and environments. Overall, their efforts focused on improving the language's compatibility, performance, and stability.
skeletonphpphp-extensionshigh-levelphalcon
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