Yevhen

YEVHEN KUPRIIUK
Back-End Engineer
yevhenkupriiuk​@gmail.com [открыть контакты](см. выше в блоке «контактная информация»)
Novovolynsk [открыть контакты](см. выше в блоке «контактная информация»)

PROFILE
Back-End Engineer with 3 years of commercial experience delivering scalable backend systems in FinTech
and iGaming domains. Strong expertise in Java ecosystem (Spring, Hibernate, JPA) and experience with
JavaScript/TypeScript backend (Express.js, Nest.js). Focused on system reliability, performance
optimization, and feature delivery across distributed systems. Comfortable working with SQL/NoSQL
databases, messaging systems, and API-driven architectures. Seeking a Middle Back-End Engineer role to
contribute to high-load, product-driven systems.

EMPLOYMENT
Java Backend Developer, Suntech Innovation 10/2024 – Present | Remote
Development and support of backend services in Java and Groovy
•

Responsibility for 3 production services, including bug fixing and incident handling
•

Participation in production support, including handling P1 incidents and hotfixes
•

Development of backend features and maintenance of existing business logic
•

Work on a TypeScript-based service introduced into the ecosystem
•

Integration with external providers
•

Direct interaction with provider APIs
•

Data collection and processing for internal usage
•

Building internal models based on provider responses
•

Development of simulation tools for provider behavior
•

Implementation of a bet placement simulator
•

Reproduction of real business flows for testing and validation purposes
•

Event-driven processing using Kafka (consumers/​producers, debugging flows)
•

Service-to-service communication using gRPC
•

Performance and reliability: SQL query optimization
•

Investigation of production issues via Kibana /​logging systems
•

Participation in release process: Release candidate preparation, Deployment and hotfix support
•

CI/​CD pipelines using Jenkins
•

Working with containerized environments using Kubernetes (Lens)
•

Mentoring newcomers (informal guidance during onboarding)
•

Software Engineer, WWG 03/2024 – 09/2024 | Ukraine
Stack: Spring /​Hibernate /​Express.js /​Nest.js
•

Developed backend services using Java (Spring, Hibernate) and JavaScript (Express.js, Nest.js) across
•

multiple concurrent projects
Designed and implemented AI-assisted questionnaire system
•

Users submitted data via Google Forms
•

System generated structured AI-based responses from input data
•

Built and maintained lead processing pipelines and integrations
•

Integrated advertising sources for lead collection
•

Automated data flows using Pipedream
•

Developed and integrated ERP-related backend functionality
•

Data synchronization between internal systems and business workflows
•

Performed root-cause analysis of production issues, resolving incidents and improving system stability
•

Implemented an in-house email validation service, reducing external validation costs by -20%
•
 Delivered features end-to-end: implementation, testing, and production release coordination across
•

parallel projects
Java Backend Developer, Life Insurance Project (NDA) 06/2023 – 03/2024 | Germany
Worked on enterprise insurance systems using Java 8/​11/​15 and Spring ecosystem
•

Maintained and extended legacy J2EE components in production systems
•

Participated in Agile planning, estimation, and delivery processes
•

Supported business-critical applications with focus on reliability and compliance
•

Communicated with stakeholders regarding system behavior and delivery status
•

Perl/Java Developer, PortaOne 12/2022 – 05/2023
Developed internal notification and reminder system integrated with Slack API
•

Adapted to Perl-based backend after Java onboarding, working with legacy architecture
•

Implemented automation tools for task tracking and reminders across teams
•

Contributed to internal workflow optimization and process automation
•

SKILLS
Java Development Spring Databases
Java Core, Java 8+, JDBC,
• Spring Core
• MySQL, SQLite, PostgreSQL,
JSP, JSTL, JPA Spring Boot
• MongoDB, FlyWay, Liquibase,
Groovy, Gradle, Kafka,
• Spring MVC
• Redis
Jenkins, Elastic (Kibana) Spring Data JPA
Version Control Systems
•

Design Patterns, Maven, Spring Security
Git, Gerrit, SVN
• •

Tomcat, JUnit, Lombok,
Postman, Docker, XML, JSON Agile Methodologies
AWS S3 bucket
•
Scrum, Kanban

Web Development Project Management Tools
CSS, HTML, SOLID, TDD, CRUD, Gemini, Jira
Grpc
Soft Skills
Teamwork, Problem-solving
•

Communication, Adaptability
•

LANGUAGES
English Ukrainian Polish
Upper-Intermediate Native Basic

ACHIEVEMENTS
Performance Optimization, Internal
Designed and implemented a simulation tool for provider behavior, increasing RPS from 120 to 500
•

through performance optimization and database normalization.
System Architecture Improvement, Internal
Developed a GRPC-based service interaction layer enabling cross-service communication and bet
•

placement logic improvements.
Built an internal multi-instance database interaction tool used across environments for controlling
•

external service behavior.
Infrastructure & Efficiency, Internal
Reduced integration test execution time from 20 minutes to 6 minutes through test optimization and
•

infrastructure improvements.
Delivered features for First Line Support (FLS), improving operational response efficiency.
•

Leadership & Mentoring, Internal
Conducted technical interviews for junior developers and participated in mentoring activities.
•