Степан

Stepan Oleksiuk Backend Engineer
stepan.oleksiuk.dev​@gmail.com [open contact info](look above in the "contact info" section)

Ivano-Frankivsk, Ukraine Linkedin GitHub Telegram

Backend Engineer focused on scalable backend systems, async processing, and AI-powered automation.
Architected and shipped production-grade backends from scratch, improved API performance by up to
70%, and reduced AI operation costs by ~50% through pipeline optimization. Experienced with FastAPI,
Django, PostgreSQL, MongoDB, Redis, Celery, RabbitMQ, Docker, and OpenAI integrations.

Experience
Backend Developer, :DTeam 2025 – Present

Multi-Service Backend Platform (FastAPI, MongoDB, RabbitMQ)
Eliminated ~50% message loss — diagnosed and fixed a critical RabbitMQ
•

consumer bug causing event drops across services
Reduced startup migration module by ~70% — moved logic to DAO/​model
•

layer, eliminating boot-time DB inconsistencies
Hardened codebase security — dependency audit surfaced 5–7
•

vulnerabilities including 2 critical severity issues, all escalated and resolved

Mobile App Backend (Django/DRF)
Architected and solely built a production Django/​DRF backend from scratch:
•

16 modular apps, 60+ REST endpoints, 33+ DB models, deployed with
Docker, NGINX, and GitLab CI/​CD
Improved critical endpoint performance by up to 70% — eliminated N+1
•

queries with select_related/​prefetch_related and applied bulk operations
Built a 4-level fallback recommendation engine: social graph → geo-
•

proximity → verified pool → global
Integrated RevenueCat handling 10 webhook event types (subscription
•

lifecycle + one-time purchases)
Delivered 6 real-time FCM notification types with per-device language
•

localization

AI Market Intelligence Tool (Python, TypeScript, React, Gemini API,
Playwright)

Cut client ad costs by 20–30% — automated keyword and campaign
•

monitoring with auto-disabling of underperforming ads
Reduced AI generation costs by ~50% by migrating to Batch API; cut data
•

collection time by ~67% through pipeline optimization
Shipped seller workflow automation across multiple production shops: AI
•

replies enriched with live CRM order context and batch fulfillment flows
 SKILLS
Web Frameworks: Databases:
Django, Django REST Framework, FastAPI PostgreSQL, MongoDB, Redis, AWS S3,
Cloudflare R2, Cloudinary
Async & Messaging:
Celery, RabbitMQ, AsyncIO, WebSockets AI & Automation:
OpenAI API, ElevenLabs, AI workflow
Web Scraping & Automation: automation, prompt pipelines, structured
Playwright, Selenium, Scrapy, BeautifulSoup outputs, batching, rate limiting

Monitoring & Observability: DevOps & Infrastructure:
Sentry, Grafana, Prometheus Docker, Docker Compose, NGINX, CI/​CD
(GitLab), Linux (SSH, cron, logs)
Testing:
Pytest, unittest, integration testing, API testing, Tools:
mocking Git, GitHub, GitLab, Postman, Swagger/​OpenAPI

Education and Qualifications
Python Developer, Mate Academy⁠ 2024
Python development at Mate academy with mentor support, practical projects, Online
databases, and testing.

Stanford CSA106+CSB106, Ш++⁠ 2023
Java-based Computer Science at School++ with peer reviews, media processing, Online
and interactive UI projects.

CS50: Introduction to Computer Science, Harvard University⁠ 2022
Аlgorithmic thinking, problem-solving efficiency, and hands-on problem sets Online
across C, Python, and web.