05/01/2026 updated
100 % available
Senior Backend Engineer (PHP, APIs, Integrations)
Krykhivtsi, Ukraine
Germany +7
Specialist Degree - Computer Systems & Networksinfo: Germany, Austria, Switzerland, France, Belgium, Netherlands, Poland, Czech Republic
About me
Backend engineer with 10+ years in PHP, focused on ERP integrations, API connectivity and data synchronization. 8 years at valantic/netz98 for the German eCommerce market. Remote from Ukraine, CET timezone, available for B2B contracts.
Clean Code PrinciplesPHPApplication Programming Interfaces (APIs)DevOpsE-CommerceElasticsearchLaravelMySQLRabbitMQRedisSystems IntegrationZend FrameworkPHPUnitBackendAdobe Magento
PHP Backend Development
Over 10 years of experience in PHP (7.4/8.x) backend development, including work with Zend Framework 1/2 and Laravel/Lumen. Focus on clean code, OOP, and SOLID principles in large-scale codebases.
API Integrations & ERP Connectivity
Extensive expertise in building and maintaining integrations with ERP systems and third-party APIs. Specialization in REST APIs, data synchronization between systems, and handling complex external dependencies.
Performance Optimization
Proven track record in backend performance optimization, including reducing live price response times by approximately 7x (1750ms to 250ms), optimizing MySQL queries, analyzing caching behavior, and building Python benchmarking tools to identify bottlenecks.
Database Management
Proficiency in MySQL/MariaDB with focus on query optimization, as well as experience with Redis and Elasticsearch for data storage and retrieval.
Python Scripting & Tooling
Application of Python for tooling, scripting, and automation, including building benchmarking tools and background services such as vehicle plate recognition using Google Vision API.
Testing with PHPUnit
Writing unit tests using PHPUnit to ensure code quality and reliability in backend systems.
Infrastructure & DevOps
Hands-on experience with Docker, CI/CD pipelines, Linux environments, and Git for version control and deployment workflows.
Code Reviews & Mentoring
Active participation in code reviews and mentoring of junior developers, promoting best practices and clean code standards within development teams.
Payment System Integration
Integration of payment systems including PayPal and Braintree into eCommerce and business applications.
Over 10 years of experience in PHP (7.4/8.x) backend development, including work with Zend Framework 1/2 and Laravel/Lumen. Focus on clean code, OOP, and SOLID principles in large-scale codebases.
API Integrations & ERP Connectivity
Extensive expertise in building and maintaining integrations with ERP systems and third-party APIs. Specialization in REST APIs, data synchronization between systems, and handling complex external dependencies.
Performance Optimization
Proven track record in backend performance optimization, including reducing live price response times by approximately 7x (1750ms to 250ms), optimizing MySQL queries, analyzing caching behavior, and building Python benchmarking tools to identify bottlenecks.
Database Management
Proficiency in MySQL/MariaDB with focus on query optimization, as well as experience with Redis and Elasticsearch for data storage and retrieval.
Python Scripting & Tooling
Application of Python for tooling, scripting, and automation, including building benchmarking tools and background services such as vehicle plate recognition using Google Vision API.
Testing with PHPUnit
Writing unit tests using PHPUnit to ensure code quality and reliability in backend systems.
Infrastructure & DevOps
Hands-on experience with Docker, CI/CD pipelines, Linux environments, and Git for version control and deployment workflows.
Code Reviews & Mentoring
Active participation in code reviews and mentoring of junior developers, promoting best practices and clean code standards within development teams.
Payment System Integration
Integration of payment systems including PayPal and Braintree into eCommerce and business applications.
Experience
Professional experience10+ years
Freelancer since2021
Languages
GermanGoodEnglishFluentUkrainianNative speaker
Project history
Worked on backend systems with multiple ERP and external integrations, large product catalog and high dependency on real-time pricing services. Built and maintained integrations with ERP systems and third-party APIs, implemented backend data processing for synchronization between systems. Reduced live price response time by approximately 7x, improved cart page performance by approximately 2x, analyzed caching behavior, built a Python benchmarking tool, optimized MySQL queries, refactored legacy backend logic, investigated and resolved production issues, wrote unit tests using PHPUnit, and participated in code reviews and mentored junior developers.
Developed eCommerce platform from early stage, extended platform APIs to integrate with ERP system, implemented inventory and order synchronization between systems, and coordinated changes between internal teams and external developers.
Developed backend services using Lumen (Laravel-based framework), built REST APIs for business and eCommerce applications, and integrated payment systems including PayPal and Braintree.