Booking System

Full-featured booking and reservation management system with real-time availability checking, conflict prevention via pessimistic locking, and Kafka-based notifications.

Key Features:

• Redis caching for high-performance availability queries
• Pessimistic locking and GiST exclusion constraints for conflict-free booking
• Kafka-based notification system for booking events
• CI/CD: GitHub Actions — automated build, test, Docker push, deploy to EC2

Production Infrastructure (AWS):

• AWS: EC2 (Spring Boot app), RDS PostgreSQL 17, S3 backups, Security Groups
• CI/CD: GitHub Actions — automated build, test, Docker push, deploy to EC2

GitHub

Time Tracking System

Enterprise-grade employee time tracking system with check-in/check-out logging, real-time presence monitoring, and automated timesheet calculation.

Features:

• Real-time employee presence tracking
• Automated timesheet calculation with daily breakdown
• Check-in/check-out logging system
• RESTful API with OpenAPI documentation

Production Infrastructure (VPS):

• VPS: Docker Compose, nginx reverse proxy, SSL/TLS (Let's Encrypt)
• CI/CD: GitHub Actions — automated build, test, deploy
• Live API: Swagger UI

View Live Demo | API Documentation | GitHub

Financial Accounting System

Enterprise-grade financial accounting system with Event Sourcing for banking operations and automatic ECB currency integration. Modular monolith architecture with comprehensive test coverage.

Core Module:

• Automatic ECB Integration - Daily sync at 16:05 CET
• 190k+ Exchange Rates - Historical data since EUR introduction
• 40+ Currencies - ISO 4217 compliant
• Public API - Real-time currency data

Banking Module:

• Event Sourcing - Immutable transaction audit trail
• Bank Receipts & Payments - 10+ transaction types each
• Document Lifecycle - DRAFT → POST → UNPOST
• Financial Reports - Balance & Turnover with filters

Quality:

• 193 tests with 97% line & 95% branch coverage
• N+1 Prevention with @EntityGraph
• CI/CD with GitHub Actions

Production Infrastructure (VPS):

• VPS: Docker Compose, nginx reverse proxy, SSL/TLS (Let's Encrypt)
• CI/CD: GitHub Actions — automated build, test, Docker push, deploy
• Monitoring: health checks, 99.5%+ uptime

Live API & Swagger | Exchange Rates Demo | GitHub

MCP Knowledge Base (GraphRAG)

AI-powered code intelligence system that indexes Java codebases and exposes structural and semantic knowledge to Claude Code via the Model Context Protocol (MCP). Combines graph database (Neo4j) for code structure with vector database (ChromaDB) for semantic search, implementing the GraphRAG pattern.

Architecture:

• mcp-indexer — scans Java source code via AST parsing (JavaParser), stores class/method graph in Neo4j and semantic embeddings in ChromaDB
• mcp-bridge — MCP server exposing 5 tools to Claude Code: class search, dependency graph, package browsing, semantic search, and GraphRAG (vector + graph enrichment)

Key Features:

• GraphRAG: semantic search enriched with dependency graph from Neo4j
• Neo4j graph schema: classes, methods, IMPORTS/EXTENDS/IMPLEMENTS relationships
• Vector embeddings via Ollama (nomic-embed-text) for natural language code search
• Dual transport: HTTP and SSE (Server-Sent Events) with session management
• Extensible parser interface for multi-language support

GitHub

Entity Generator

JPA entity generator for PostgreSQL databases. Automates creation of Java entities from existing database schemas.

View on GitHub

All Projects

Explore all my projects and contributions on my GitHub profile:

https://github.com/TarasAntoniuk