Роман

ROMAN PAVLIUK
Java Backend Developer — Payments & Card Processing
Rivne, Ukraine (Remote) | [відкрити контакти](див. вище в блоці «контактна інформація») | [відкрити контакти](див. вище в блоці «контактна інформація»)
LinkedIn: [відкрити контакти](див. вище в блоці «контактна інформація»)

SUMMARY
Java backend developer with ~4 years of commercial experience, focused on payment and card-processing
systems. Built and maintained microservices processing thousands of payment transactions per day, and
integrated card payment gateways (including UPC) on a production e-commerce platform. Strong with Spring
Boot, PostgreSQL, REST APIs, and microservice communication over Kafka and RabbitMQ. Comfortable owning
a module end-to-end — from schema and API design to deployment — and collaborating with QA and analysts.

SKILLS
Languages: Java (primary), Kotlin (basic), PHP
Frameworks: Spring Boot, Spring Security, Yii2
Databases: PostgreSQL, MySQL, Redis — schema design, indexing, query optimization
APIs & Architecture: REST API design, Microservices, OpenAPI/Swagger, JWT auth
Messaging: Apache Kafka, RabbitMQ
Payments: Card transaction processing, Fiscalization (Checkbox), Ridango, LiqPay / UPC, Loyalty systems
DevOps: AWS, CI/CD (GitHub Actions, Jenkins), Docker, Gradle, Maven, Git

EXPERIENCE
Mobimill — Java Backend Developer Aug 2022 – Present
X24 — Card & Payment Processing Platform (Transport Ticketing), Kyiv / Bucha / Lviv
Java, Spring Boot, Spring Security, REST, PostgreSQL, Redis, Kafka, RabbitMQ, Microservices, Gradle, Jenkins
• Built and maintained Spring Boot microservices processing thousands of payment transactions per day
across 3 cities, with transaction validation (Ridango) and fiscalization (Checkbox).
• Developed 24 microservices and extended ~30 more within a 120+ service platform; integrated services via
Kafka (event streaming) and RabbitMQ (device communication).
• Worked with PostgreSQL for transactional data — schema design, indexing, and query optimization.
• Built the backend for the “Mobile Cashier” application, plus admin panels and reporting.
SaatBau — E-commerce, Payments & Loyalty
PHP/Yii2, Java/Spring Boot (fiscal service), MySQL
• Integrated card payments (LiqPay / UPC) with fiscal-receipt generation via a dedicated Spring Boot service,
using the bill amount as the single source of truth for rounding.
• Designed and shipped a loyalty/bonus system (accrual, audit log, recalculation) and automated payment-
reminder flows.
Mobile REST APIs (Syngenta Scanner, AdamaUSA)
PHP/Yii2, REST, JWT, AWS
• Designed 100+ REST endpoints for production mobile apps, with device-first JWT authentication and multi-
market i18n.
FieldInfo — Field Reporting Service (reliability ownership)
Java, Spring Boot, AWS
• Diagnosed and eliminated recurring weekly production hangs caused by missing HTTP-client timeouts;
stabilized the service.
Address Register — Address Registration System of Ukraine
Java, Spring Boot, MySQL, Kafka
• Resolved API defects, developed new features, and processed address updates.
Wizzness — Java Developer May 2022 – Aug 2022
Java, Kotlin, Spring Boot, MySQL

• Contributed to backend development in Java and Kotlin; built admin panels and integrations (Nova Poshta,
Instagram).

PERSONAL PROJECTS
tournaments-v1 — Owned end-to-end (product backend)
Spring Boot 4, Java 17, REST, GitHub Actions, Oracle Cloud ARM64
• Solely designed and shipped a full backend — stateless HMAC-SHA256 auth, role-based permissions, REST
API, leaderboard engine — with a CI/CD pipeline deploying to an ARM server.

EDUCATION
Java Programming Course: 2021
International University of Economics and Humanities: Specialist, Enterprise Finance, 2012–2015

LANGUAGES
Ukrainian — Native | English — A2 (improving)