Technical Skills
Technologies and practices Rostyslav Zakroishchykov applies across AI integration, payment systems, high-load APIs, and maintainable backend architecture for production environments.
Languages & Frameworks
- Python
- FastAPI
- Django
- Node.js
- Express.js
- TypeScript
- JavaScript
- SQL
Cloud & Infrastructure
- AWS
- AWS Lambda
- Celery
- Docker
- Serverless
- Environment-based config (dotenv)
Databases & Caching
- PostgreSQL
- SQLAlchemy
- Redis
- Query optimization
- Indexing
- Multi-layer caching
Architecture & APIs
- REST API design
- Clean Architecture
- SOLID principles
- Dependency Injection
- Microservices
- Webhook integrations
- Rate limiting
- Zod / express-validator
Payments & Security
- Payment gateway abstraction
- Idempotent transactions
- Webhook verification
- JWT authentication
- RBAC
- Refresh token rotation
- Stripe / Plaid-style flows
AI & Document Processing
- RAG pipelines
- Vector search
- Embeddings
- ChromaDB
- LLM prompt engineering
- OCR
- PDF ingestion
- Structured JSON extraction
Engineering Practices
- Event-driven workflows
- Background jobs
- Retry & failure recovery
- Code reviews
- Mentoring
- Production debugging
See how these skills were applied in production at Upwork, Compass Mining, and CryptoDrilling, or explore services.