Hi, I’m Roman, welcome to my site.

In the early 2000s I studied at the University of Radio Electronics extension courses, specializing in Web Development.

In 2009 I started my career in the EU as a Web / PHP Developer.

I have worked on many interesting projects as an Android Developer, Java Backend Developer, Web Developer, and in recent years as an AI / ML Engineer.

Around 2021 I began writing articles on Medium on topics that interest me, to contribute and help aspiring developers and others; I then created this site.

I was born in Ukraine, Kharkiv.

If you spot an error or think something should be added, reach out: https://t.me/RomanKryvolapov

LinkedIn: https://www.linkedin.com/in/roman-kryvolapov/

GitHub: https://github.com/RomanKryvolapov

Medium: https://medium.com/@roman-kryvolapov

My tech stack:

Core Tech Stack:
Java, Kotlin, Spring, Android

Languages:
Kotlin, Python, Java, TypeScript, C++, PHP

Architecture:
OOP, Clean Architecture, SOLID, Reactive Programming, MVVM, MPV, MVI, MVC, Architectural Patterns, Saga, Event Sourcing, DDD, TDD, Microservices

Multithreading:
Python Multiprocessing, RxJava, Kotlin Coroutines, Kotlin Flow, Spring WebFlux

SQL Databases:
SQL, ACID, PostgreSQL, MySQL, SQLite, JPA / Hibernate, JDBC / JDBI, Transaction Management, Room, Exposed, Liquibase, Flyway, GIN

NoSQL Databases:
MongoDB, DataStore, Redis

Vector Databases:
Chroma, Faiss, Milvus, PgVector, SQLiteVec

Web:
RESTful API, Wasm, Spring Boot, Spring Web, Ktor, FastAPI, WebSocket, WebRTC, Servlets, gRPC, SOAP, OkHttp, Retrofit

Cloud:
AWS S3 / EC2 / ECS / App Runner / SNS / SQS / Kinesis Streams / Lambda / KMS, Google Cloud / Firebase, Kafka, RabbitMQ, Kubernetes, Prometheus, Grafana, Grafana Loki, Promtail, Docker, Docker Compose, Nginx, Tomcat, n8n

Security:
Keycloak, OAuth, Spring Security, TLS/SSL/mTLS, KMS, OWASP

CI/CD:
GitHub Actions, GitLab CI/CD, Jenkins

Frontend:
Angular, jQuery, Bootstrap, Thymeleaf, Freemarker, Mustache, HTML, CSS

DI:
Dagger, Koin, Hilt, Spring DI

Testing:
jUnit, Mockito, Mockk, Espresso, PowerMock, TestContainers, Charles Proxy, Postman, JMeter, ApacheBench

AI:
RAG, CAG, Transformers, AI Agents, DSPy, LangChain, LangGraph, ElevenLabs, Google MediaPipe / TensorFlow Lite, PyTorch, Pandas, llama.cpp, LiteRT, MLC LLM, ONNX, LoRA Adapters, LM Studio, Ollama, Unsloth, ChatGPT API, Gemini API, AST, MCP

Other:
Git, Android, ElasticSearch, Javadoc, Lombok, MapStruct, Material Design, Linux Administration