Даниїл

Danyil Lytvynov
Location: Varna, Bulgaria | Email: [відкрити контакти](див. вище в блоці «контактна інформація») | LinkedIn: [відкрити контакти](див. вище в блоці «контактна інформація»)
lytvynov

Summary
Backend Developer with nearly 3 years of experience building scalable systems in Erlang/OTP and
Python. Proven ability to design concurrent architectures, integrate 20+ third-party services (REST
APIs, OAuth2, webhooks), and optimize performance in distributed environments. Experienced in
Django web development and relational databases. Strong collaborator with code review and
mentorship experience. Seeking a challenging backend role in an international team.

Experience
Back-end Developer, DigitalBPM – Kyiv, Ukraine (Jul 2023 – Dec 2025)
-Developed and maintained core backend services using Erlang/OTP, focusing on stateful processes,
concurrency, and asynchronous message passing.
-Owned and evolved a workflow engine, implementing event processing, trigger handling,
scheduling, and chaining of business processes.
-Built and integrated billing and subscription management features (tariff plan
upgrades/downgrades, invoice generation, subscription lifecycle).
-Created reusable workflow templates to enable quick creation and customization of automation
scenarios.
-Implemented 20+ external integrations (REST APIs, OAuth2, webhooks) with major third-party
services (Google, Microsoft, Meta), resolving technical blockers for new and existing integrations.
-Optimized request routing in a multi-service architecture, reducing unnecessary parsing and
validation overhead.
-Improved system reliability by extending event logging, enhancing error reporting, and introducing
automated tests for critical workflows.
-Contributed to technical decision-making and performed code reviews, while mentoring three
junior developers through onboarding and guidance.
Sales Manager, Jelinek–Interier s.r.o. – Prague, Czech Republic (Sep 2023 – Feb 2025)
-Managed client relationships and sales processes, demonstrating strong communication and
customer service skills in an international environment.

Education
National Technical University "Kharkiv Polytechnic Institute" – Kharkiv, Ukraine (2021–2025)
B.Sc. in Computer Science. Relevant coursework: Data Structures & Algorithms, Object-Oriented
Programming (C++), Web Development (Python/Django), Database Systems (SQL).

Projects
E-Commerce Platform with JWT Auth & Personalized Recommendations – Individual project
(Bachelor’s thesis) – Django, Django REST Framework, SQLite
-Built a three-tier web application for an online marketplace using Django and Django REST
Framework.
-Implemented secure user authentication and role-based access control with JSON Web Tokens
(JWT) and RSA encryption.
-Developed a product recommendation engine based on user behavior, applying TF-IDF text analysis
to product descriptions.
-Implemented RESTful API endpoints for user management, product listings, messaging, and
recommendations.
-Created responsive UI pages with HTML, CSS, and JavaScript to ensure usability across devices.
-Designed a normalized relational database schema with Django ORM to enforce data integrity.
-Wrote unit tests to verify API functionality and user workflows.
Detecting Shell Craters on Satellite Images – Team project – Python, Docker
-Developed backend components in Python to support satellite image analysis for crater detection.
-Containerized the application with Docker for consistent development and deployment
environments.
-Collaborated with the team on system design, taking ownership of key features and ensuring high
code quality through code reviews.
English Learning Assistant "Wordly" – Pet project – Erlang, PostgreSQL, Telegram Bot API, Cowboy,
Docker
-Developed a Telegram bot for interactive English learning with multiple game-based practice
modes.
-Built a concurrent backend in Erlang/OTP using supervisors and fault-tolerant processes, with in-
memory ETS for fast per-user state management.
-Designed a PostgreSQL data model for vocabulary, exercises, and user progress; implemented
scoring and leaderboard features for user competition.
-Implemented real-time updates via HTTP webhooks (Cowboy) and integrated the Telegram Bot API
for seamless user interactions.
-Created flexible task generation logic with randomized options, adaptive feedback, and automated
result evaluation.

Skills
 Programming: Erlang/OTP, Python (Django, Django REST Framework), C++
 Web & APIs: REST API design, OAuth2, Webhooks, HTML/CSS
 Databases: PostgreSQL, SQLite
 Tools & Platforms: Docker, Linux, Git (version control)

Languages
English: B2 (Upper-Intermediate) | Czech: B2 (Upper-Intermediate) | Ukrainian: Native