Valentin

Valentyn Korol
Senior Backend Engineer | PHP / Laravel | Go
Burgas, Bulgaria (EET, UTC+2) · Remote | [open contact info](look above in the "contact info" section) | [open contact info](look above in the "contact info" section) |
[open contact info](look above in the "contact info" section)

PROFESSIONAL SUMMARY
Senior Backend Engineer and Certified Senior Laravel Developer with 5+ years of commercial
experience in PHP/Laravel and Go. Built from scratch a high-load Amazon marketplace
operations platform for a catalog of ~100M products with 200–300K price updates per day.
Strong in asynchronous processing (Laravel Queues, Horizon, RabbitMQ, Redis, Go worker
pools), third-party API integrations and PostgreSQL performance. Focused on system
reliability and maintainable architecture.

TECHNICAL SKILLS
Languages & Frameworks: PHP 8+, Laravel, Go (Golang)
Databases & Caching: PostgreSQL, MySQL, Redis, SQL optimization, indexing
Messaging & Processing: RabbitMQ, Laravel Queues, Laravel Horizon, asynchronous
workflows, background jobs, worker pools
APIs & Integration: REST API, Amazon SP-API, third-party APIs, data synchronization, rate
limiting, retries
Go: goroutines, channels, context, interfaces, concurrency, error handling
Tools & Practices: Docker, Linux/Ubuntu, Git, GitHub, CI/CD (Continuous Integration /
Continuous Delivery), unit testing (PHPUnit), feature testing, dependency injection

PROFESSIONAL EXPERIENCE

Senior Backend Engineer (PHP/Laravel, Go) 04/2024 - 10/2026
Z Global E-Commerce LLC, Remote (USA)
• Built from scratch an Amazon marketplace operations platform for a catalog of ~100M
products: supplier product sync, inventory monitoring, listings, competitive offer analysis
and automated repricing.
• Designed asynchronous processing pipelines (Laravel Queues, Horizon, RabbitMQ, Redis,
scheduled jobs) handling 200–300K price updates per day.
• Built the repricing engine based on competitor offers, supplier prices, fulfillment costs,
marketplace fees and configurable profitability rules.
• Integrated Amazon SP-API and supplier APIs with rate limiting, retries and error handling to
keep marketplace data in sync.
• Optimized PostgreSQL queries and indexes for product tables with millions of rows.
• Developed Go services and background workers for high-volume product and offer
processing, using worker pools, channels and context-based cancellation.
• Wrote unit and feature tests with PHPUnit.

Senior PHP Developer 03/2023 - 04/2024
Accentiko, Remote (Canada)
• Developed backend services for a healthcare platform connecting doctors and patients,
used by tens of thousands of users.
• Designed and implemented REST APIs for client applications and external integrations.
• Built business logic for scheduling, workflow management and user activity tracking.
• Refactored legacy modules and added unit and feature tests (PHPUnit) to improve reliability
and maintainability.

PHP/Laravel Developer 05/2022 - 03/2023
AYARS Tech
• Built and maintained Laravel applications: backend modules, admin panels and REST API
endpoints.
• Worked with MySQL and PostgreSQL, Git-based deployment workflows and frontend
integrations.
Junior PHP Developer 05/2021 - 05/2022
Artjoker
• Developed PHP/Laravel features and backend functionality, including JavaScript, jQuery
and AJAX integrations.

Trainee PHP Developer 04/2021 - 05/2021
AWEB

CERTIFICATION
Senior Laravel Developer — Certification for Laravel (verified)
https://verifier.certificationforlaravel.org/b62cf016-7f93-4fa0-ac45-0998fff2eb34

EDUCATION
Kharkiv Regional Institute of Public Administration (NAPA) — Master of Public Administration
(2019–2020)
Kharkiv National University of Civil Engineering and Architecture — Master's degree,
Construction Engineering (2008–2013)

LANGUAGES
Ukrainian — Native; English — B1+ (professional working proficiency)

WORK AUTHORIZATION
Temporary protection status in Bulgaria (EU). Available for remote work as an independent
contractor (B2B, Ukrainian sole proprietor).