Сергій

Sergii Gainovskyi
Java Developer
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Skills Cloud & DevOps
Languages & Core AWS (EC2, RDS, ECR, S3, CloudWatch, Load Balancer /
Java (Core, JDK 8–21) Auto Scaling)
HTML, CSS, JavaScript(basic) Hetzner , Nginx
Python Testing & Automation
OOP, SOLID, Design Patterns (GoF) JUnit, Mockito
Frameworks & Libraries Postman
Spring (Core, Boot, Web, Security, Data JPA) Build & Dev Tools
Hibernate, JDBC Maven, Gradle
Swagger Git, GitHub, Docker
Servlets, Tomcat IntelliJ IDEA
Databases Other
PostgreSQL, MySQL, SQLite JSON, Trello, Jira
Liquibase (DB versioning English – B2 (Upper-Intermediate)

Experience
Play Fusion Labs 01.09.2024 - 01/06/2025
Java software developer
Astra nova
Implemented logic for authentication and authorization of users
Implemented security for user accounts
Implemented logic to manage user account details
Implemented logic to transfer information between the game server, database, and AstraNova Black
Pass server
Implemented quest registration and reward system
AWS infrastructure: RDS, EC2, ECR, LB
Technologies: Spring Boot, Spring Security, Spring Data JPA, Liquibase, Maven, MySQL, Docker, REST API,
RDS, EC2, ECR, LB, GitHub Actions

Flatorio
Implemented user registration service
Implemented user security service
Developed logic for users to create and manage their own projects
Enabled users to add 3D models to projects
Implemented a save system that ensures models are preserved when the app is closed
Developed an admin management system allowing full control over models and projects
Implemented project visibility levels for better access management
Added email notifications for user updates and system events
Integrated subscription management for users
Integrated Stripe for seamless payment processing
Designed and managed AWS cloud infrastructure, including EC2, RDS, ECR, S3, Load Balancer, Auto
Scaling, and CloudWatch
Technologies: Spring Boot, Spring Security, Spring Data JPA, Liquibase, Maven, Postgres, Docker,
REST API, RDS, EC2, ECR, LB, S3, GitHub, Stripe, HTML, CSS
 National Land Lease
Deployment and configuration of server infrastructure on the Hetzner platform
Setup of the Coolify service on the server
Configuration of VPC on the server
Nginx configuration
SSL certificate integration
Backup implementation
Transfer server to new domain name

Technologies: Hetzner Cloud, Linux (Ubuntu/Debian), SSH, Coolify, Docker, Docker Compose, Virtual
Private Cloud (VPC), Nginx, Let's Encrypt, Certbot, OpenSSL, rsync, cron, BorgBackup, Restic,
Duplicity, DNS (A, CNAME, TXT записи)

Java software developer 2023 - 2024
Online Book Store Project
An advanced online bookstore application developed with Spring Boot, featuring functionalities like user
registration, book browsing, shopping cart management, and order processing.
Developed and maintained RESTful services to handle user sign-up, book catalog browsing, and order
workflows.
Ensured secure user authentication and authorization through Spring Security and JWT
implementation.
Handled database operations with Spring Data JPA and managed migrations with Liquibase.
Conducted comprehensive unit testing with JUnit and Mockito to ensure high code quality and
reliability.
Integrated Swagger for API documentation and streamlined testing processes.

Technologies: Spring Boot, Spring Data JPA, Spring Security, Liquibase, Maven, MySQL, Docker, Swagger,
JUnit, Mockito, GitHub Actions, H2 Database, Collections, OOP, Hibernate, JSON, Spring Web, Mockito, Docker,
Liquibase, Postman etc.

Accommodation-booking-app
A full-featured rental platform with role-based access, secure cashless payments (Stripe), and real-time
updates via Telegram notifications. Managers can manage listings and orders; users can book and pay
online.
Designed and implemented the Booking domain model and entity relationships.
Built RESTful BookingController with full CRUD and custom endpoints.
Developed service and repository layers with validation and transactional logic.
Implemented DTO mapping for clean request/response handling.
Managed database versioning and schema updates via Liquibase.

Technologies: Spring Boot, Spring Security, Spring Data JPA, Liquibase, Maven, MySQL, Docker, Telegram
Notifications Service, Stripe, JUnit, Mockito, GitHub Actions, H2 Database