Назар

NAZAR KLYMCHUK
Python Backend Engineer

[open contact info](look above in the "contact info" section) | Telegram | GitHub | LinkedIn | Lutsk, Ukraine

PROFESSIONAL SUMMARY
Python Backend Engineer with 4+ years of commercial experience building and maintaining production
systems using asynchronous Python, FastAPI, PostgreSQL, and Redis. Designed and evolved backend
architectures for payment, subscription, and ordering platforms serving thousands of customers,
including modernizing tightly coupled applications into maintainable, domain-oriented systems.
Owned end-to-end backend delivery, from requirements analysis and system design to third-party
integrations, deployment, troubleshooting, and long-term production support.

WORK EXPERIENCE

Independent Python Backend Engineer Mar 2022 - Present
Contract / Client Projects
Delivered 50+ commercial backend and automation solutions across independent client
engagements, with 10+ systems still in active production use.
Designed and evolved production backend architectures, including the migration of a subscription
platform to a domain-oriented modular monolith serving 3,800+ registered users and managing
1,000+ subscriptions.
Built multi-platform integrations and automated business workflows across messaging platforms,
payment providers, and CRM systems, including an ordering solution serving 5,000+ Telegram
customers and 1,300+ Viber users.
Validated critical subscription and promotional workflows using unit and integration tests with an
isolated PostgreSQL test environment.

Middle Python Backend Engineer May 2024 - Oct 2025
Web3 Startup (Confidential) | Contract
Owned development, deployment, and production support of the core asynchronous Python
backend, integrating multiple blockchain networks.
Implemented application-level per-address locking, transaction-state tracking, and confirmation
checks to coordinate concurrent operations, with scheduled retries for failed or timed-out
operations.
Developed advertising attribution and social-platform integrations for conversion tracking, session
management, and API-based automation.
Resolved event-loop blocking in a legacy integration by moving long-running synchronous I/O to
threads, keeping asynchronous services responsive during external calls.

Founder & Backend Engineer May 2023 - Feb 2024
Devevo
Founded and scaled a software development agency to a cross-functional team of up to 25
specialists, personally recruiting core developers and conducting technical interviews.
Led backend engineering for selected client projects, driving Python development, technical
design, and implementation of commercial e-commerce and automation solutions.
Combined hands-on development with engineering coordination, defining technical requirements,
reviewing contributions from junior developers, and overseeing delivery from implementation to
release.

PROJECTS

Aiober — Open-Source Asynchronous Python Library 2023 - 2024
Developed reusable asynchronous abstractions for the Viber API, simplifying webhook-based bot
development and external integrations.
Adopted in a production ordering platform serving 1,300+ users, demonstrating practical value
beyond an experimental library.

TED — Personal Automation & Infrastructure Monitoring Sep 2026 - Present
Designed an event-driven backend platform using Python and NATS JetStream for
communication between independent services and centralized automation.
Implemented infrastructure monitoring with Rust agents, persistent TCP connections, heartbeat
checks, and automated alerts on connection failures.

Karum — Open-Source Financial Aggregation Backend 2026
Built an asynchronous Python backend integrating Monobank, Bybit, and OKX through provider
adapters for transaction synchronization and consolidated financial reporting.
Applied Clean Architecture with domain-driven boundaries, repository abstractions, Unit of Work,
and PostgreSQL persistence using async SQLAlchemy and Alembic.

Snizhok — Student Learning & Management Platform 2021 - 2024
Developed and re-architected a student platform for class schedules, assignment tracking, and
automated reminders, expanding it to 132 users across 12 study groups.
Expanded the educational initiative into NMT exam preparation, supporting a separate Telegram
community of 100+ members with daily practice tests and curated exam questions.

SKILLS
Programming Languages · Python, Rust (basic)
Databases & Persistence · PostgreSQL, Redis, SQLite, MySQL, SQLAlchemy, Alembic
Backend · FastAPI, aiohttp, aiogram 3, Pydantic, AsyncIO, Playwright
Architecture & Design · Clean Architecture, Modular Monolith, Microservices, Dependency
Injection, Event-Driven Systems
Communication & APIs · REST APIs, Webhooks, gRPC, NATS JetStream
Testing & Validation · Unit Testing, Integration Testing, pytest, PostgreSQL Test Environments
Infrastructure · Docker, Kubernetes, Nginx, Linux, CI/CD, GitHub Actions
Integrations · Payment Systems, Blockchain APIs, Telegram/Discord/Viber API, Third-Party APIs,
Web Automation

LANGUAGES
Ukrainian: Native
English: B2
Polish: A2