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Illia Stepenko
Senior Python Backend Developer
Telegram: t.me/pk_4519303 | Email: [open contact info](look above in the "contact info" section) | LinkedIn: [open contact info](look above in the "contact info" section)

PROFILE
Python backend developer with 6+ years of commercial experience building and maintaining fintech, ERP,
media-streaming, blockchain, and automation systems. Strong specialization in Django and FastAPI, asynchronous
processing, PostgreSQL, Redis, AWS, API integrations, and production-oriented service architecture. Experienced in
taking ownership of backend features and delivering reliable systems across complex business domains.

CORE SKILLS
Backend Python, Django, Django REST Framework, FastAPI, SQLAlchemy
Data & async PostgreSQL, RDS, DynamoDB, Redis, Celery
Cloud & DevOps AWS (EC2, S3, Lambda, MediaConvert), Docker, Grafana, Loki, Sentry
Frontend React, TypeScript, Vue, HTML/CSS
Blockchain Ethereum, Arbitrum, BNB Chain, Optimism, Solidity, Hardhat
Testing & AI pytest, integration testing fundamentals, OpenAI API, LLM-based automation

PROFESSIONAL EXPERIENCE
Flexipy OÜ — Full-Stack Developer | 2026
• Designed and implemented backend features with Python and FastAPI for core business logic and internal
workflows.
• Built and maintained API integrations, including data processing, validation, and communication with external
services.
• Refactored existing code to improve reliability, readability, and maintainability; supported coding-practice and
workflow improvements.
• Used AI development tools and agent-based automation to accelerate routine engineering tasks and improve
development workflows.
• Supported frontend work with React/TypeScript, including components, UI fixes, and API integration.
• Maintained background processing with Celery/Redis and contributed to testing and QA.
Tech: Python, FastAPI, SQLAlchemy, React, TypeScript, Docker, Redis, Celery, pytest
Blackrocksoftware — Backend & Smart Contracts Developer | 2025–2026
• Designed and implemented backend services for a crypto payment gateway supporting merchants across
Ethereum, Arbitrum, BNB Chain, and Optimism.
• Built wallet-monitoring and transaction-processing logic to detect incoming on-chain payments and confirm
transactions.
• Developed and deployed Solidity smart contracts using a splitter mechanism for merchant payouts and platform
fees.
• Implemented asynchronous transaction-processing pipelines with Celery and event-driven workflows.
• Added real-time merchant notifications and robust transaction validation/error handling for financial operations.
• Implemented application monitoring with Grafana and Loki.
Tech: FastAPI, PostgreSQL, SQLAlchemy, Celery, Grafana, Loki, Solidity, Hardhat, Remix
Software development hub — Full-Stack Developer | 2023–2025
• ERP system for a charity foundation: designed and implemented warehouse management, financial reporting,
support-request processing, document management, and logistics-routing functionality.
• Integrated external services including PUMB banking and Nova Poshta delivery APIs for financial and shipment
workflows.
• Implemented asynchronous jobs with Celery/Redis for reporting, integrations, and notifications.
• Deployed and maintained the system in AWS, using EC2, S3, PostgreSQL/RDS.
• Media streaming server: implemented large-file uploads with S3 multipart upload and video-processing pipelines
with AWS MediaConvert for MPEG-DASH.
• Built dynamic MPD manifest manipulation for multi-language audio tracks and subtitles; integrated Amazon
Transcribe for subtitle generation/translation.
• Integrated OpenAI API for image descriptions and optimized metadata/file access with AWS Lambda and
DynamoDB.
Tech: Django, Celery, Redis, PostgreSQL, RDS, React, AWS EC2/S3/Lambda/MediaConvert, DynamoDB, OpenAI API, boto3,
Sentry
SoftFormance — Backend Developer | 2022–2023
• Independently designed and developed core functionality for a platform processing and visualizing environmental
pollution and harmful-emissions data.

• Implemented data-processing and analytics features and maintained background task processing.
• Contributed to an online-store platform and a service marketplace connecting providers with customers.
Tech: Django, Celery, Redis, PostgreSQL, Docker, jQuery
Center for Information and Analytical Technologies — Backend Developer | 2020–2022
• Contributed to a financial accounting system for public-sector budget organizations.
• Improved existing functionality and developed reporting systems.
• Implemented data exchange with 1C.
Tech: Django, Celery, Redis, PostgreSQL

EDUCATION
Cherkasy State Technological University — BSc, Computer Science (2013–2017)
State University of Information and Communication Technologies — Master’s studies, Computer Science (2017–2020)

LANGUAGES
English — Upper-intermediate & improving | Polish — Intermediate & improving | Ukrainian — Native