Маркіян

MARKIIAN POTIUK
B A C K E N D D E V E L O P E R

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PROFILE
[open contact info](look above in the "contact info" section)
Backend Developer with 1.5+ years of commercial experience
Lviv, Ukraine developing and maintaining server-side applications and
RESTful
https://t.me/ImJustM4rk APIs. Experienced in transaction logic, relational database
optimization, and multi-channel integration. Focused on writing
clean, testable code and delivering reliable backend solutions
in team environments.

SKILLS
Backend: Node.js, Python, Java EXPERIENCE
Frontend: JavaScript,
BACKEND DEVELOPER
TypeScript, Angular
Databases: PostgreSQL, MySQL VISA
Build & Deploy: Docker, Maven, 2024 - 2026
Git - Optimized SQL queries to PostgreSQL for schedule search and
Architecture: RESTful APIs & booking status endpoints by adding indexes to frequently filtered

Transactions fields, which reduced query execution time on the busiest routes
- Implemented caching for train schedule queries (Redis),
Infrastructure: System Admin &
reducing the number of repeated database queries during peak
Networking loads
English - B2 - Developed REST API endpoints for ticket refund scenarios with
business rule validation (refund deadlines, fees), which reduced

EDUCATION the number of erroneous requests from client applications
- Wrote unit and integration tests for the payment logic, covering

ASSOCIATE DEGREE IN edge-case scenarios (duplicate transactions, payment gateway
COMPUTER SCIENCE timeouts), which reduced the number of regression bugs in

Technological College of Lviv releases
Polytechnic National University - Helped configure error logging in Corezoid processes, which

2022 - 2026 accelerated the detection of integration failures with the
payment provider
- Participated in code reviews and refactoring of outdated state
machine processes in Corezoid, improving the readability and
consistency of the reservation processing logic