Denis Galetin

Professional Experience

• Denis Galetin IE

  Tbilisi, Georgia

  Individual Entrepreneur

  January 2023 → Present

  Venson Ltd.

  Cyprus · Service Contract

  Senior Backend Developer (PHP/Go)

  January 2023 → Present

  Led monolith-to-microservices migration: extracted deposits and withdrawals services, reducing deployment time from 2 hours to 15 minutes. Continuing architectural decomposition in a team of 5 backend developers

  Design system architecture, document technical decisions, and conduct code reviews. Mentor 2 middle developers, help with architectural decisions

  Develop payment APIs for financial services

  Configure CI/CD pipelines to automate deployment and testing. Manage Kubernetes clusters on AWS for production workloads

  Write unit and integration tests for critical services, set up monitoring and alerting. Achieved 99.8% uptime SLA for payment services through systematic reliability improvements and incident response processes

  Optimize slow SQL queries: reduced reporting query execution time from 8 seconds to 200 ms, enabling real-time reports for 200k+ users

  Refactor legacy code, apply SOLID principles and design patterns

  Develop internal tools to automate team's routine tasks

• Albato

  Setúbal, Portugal

  PHP Developer (contract)

  June 2021 → December 2022

  Worked on integration platform backend connecting 200+ third-party services, processing 50k+ API requests daily for 3k+ active business clients

  Built PHP worker system for asynchronous processing of CPU-intensive automation tasks, accelerated automation execution by 60% through parallelization

  Optimized database architecture and slow queries, improving response times for critical endpoints

• Paykassma

  Worldwide

  PHP Developer

  February 2019 → June 2021

  Worked across two product teams within Paykassma's company group over 2+ years: launched on the gateway product team, then moved to the core fintech platform - taking on broader ownership of payment infrastructure

  Developed payment gateway backend with embeddable iframe widget; integrated multiple payment providers through a unified API gateway with retry and webhook notification system for payment statuses

  Set up transaction table partitioning by dates: split a 50M+ record table into monthly partitions, automated archiving of data older than 6 months - eliminating performance degradation as data grew

  Integrated payment gateway with multiple banks and processing centers; developed internal API for transactions and user balance management

  Optimized SQL queries and database structure: refactored transactional queries, added indexes on frequently accessed fields, reduced response time from 2-3 seconds to 100-150 ms

  Covered critical financial operations with tests, implemented automated e2e testing

  Set up transaction monitoring and alerting for payment anomalies

  Optimized payment processing pipeline: eliminated redundant logic and unnecessary DB round-trips, improving throughput under load

• Freelance & Startup Projects

  Freelance PHP Developer / Startup Projects

  January 2017 → February 2019

  Developed web applications and payment integrations for small businesses and startups

  Worked directly with clients: gathered requirements, designed solutions, maintained launched projects

  Managed full project lifecycle independently: provisioned Linux VPS environments, configured Nginx, MySQL, and PHP-FPM from scratch, handled deployments and production support

  Participated in a startup project in the online payments space, gained first experience with high-load systems

Technical Skills

Soft Skills