vesmirov

• Maintained and extended the core billing system ($150M+ annual revenue, 35,000+ clients, 5 regions, multiple currencies) within a microservice distributed architecture, processing millions of monthly transactions • Independently integrated regional payment providers end-to-end (payment initialization, status tracking, settlement, fiscal receipts), enabling card payments in new markets and supporting multi-currency geographic expansion • Led a cross-functional project to redesign the referral reward system (1,000+ partners, ~9% of company revenue): shifted payout calculations from gross spending to actual payments received, replaced flat-rate tax withholding with progressive rates applied at withdrawal instead of accrual - in coordination with the payments department, ERP, and business stakeholders, automating tax calculations previously processed manually • Designed the correction transaction architecture for the migration: isolated transaction types to preserve downstream tax and payout logic, split adjustments by fiscal year, and handled progressive tax threshold edge cases with custom SQL verification on staging Stack: Python, Flask, SQLAlchemy, PostgreSQL, Pydantic, Celery, RabbitMQ, Redis

• Designed and implemented decomposition of a monolithic ML inference service (NER, text analysis, translation) into 11 language-specific microservices (Docker/Helm/K8s) with request routing by language; sole maintainer for 3 months • Built the Google Vision integration module; led architectural restructuring of the image processing system; increased test coverage of the core module ~9x • Refactored the LLM integration layer during GPT-3 to GPT-4 migration, implemented structured response persistence in PostgreSQL, maintained prompt-based ad generation system • Extended and maintained the backend of an AI-powered ad generation platform, contributing to the data processing pipeline from NLP analysis through content delivery Stack: Python, Django, Flask, GraphQL (Graphene), PostgreSQL, Docker, Kubernetes, GCP

• Built an API integration layer for a major Asian technology company, delivering an MVP that secured an enterprise partnership contract • Developed and maintained REST APIs for a global CDN platform (140+ points of presence across 6 continents), implementing content distribution logic and caching layer optimizations Stack: Python, Django, DRF, FastAPI, PostgreSQL, Celery, RabbitMQ, Redis, Docker, Kubernetes