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Oleksii Telenchak
[open contact info](look above in the "contact info" section) |[open contact info](look above in the "contact info" section) | LinkedIn | Github
PROFESSIONAL SUMMARY
Full-stack developer with a backend focus and commercial delivery experience. Built and operate a production
multilingual Next.js website for a Dutch client as the sole developer, from architecture to launch in one month. Core
stack: TypeScript, React/Next.js, NestJS, PostgreSQL, Prisma, Redis, Docker. Comfortable with relational data
modelling, REST API design and covering code with unit tests.

TECHNICAL SKILLS
Languages: TypeScript, JavaScript, SQL, HTML/CSS
Backend: Node.js, React, NestJS, REST APIs, Server-Sent Events (SSE), session/JWT auth
Databases & ORM: PostgreSQL, Prisma, Redis
Tools & Practices: Git / GitHub, Linux, Docker

EXPERIENCE
Freelance Full-Stack Developer - YA Clean Experts (client), Remote | Next.js, React, TypeScript, Umami, Vercel | July
2026 - October| yacleanexperts.nl
● Delivered a production multilingual (NL/EN/UK) website for a Dutch cleaning company as a paid freelance
client project, owning the full cycle from architecture to launch.
● Built dynamic per-service request forms with branded transactional email notifications over SMTP, replacing
the client's manual phone-based intake.
● Deployed and operated the stack across Vercel with DNS via TransIP.
● Set up cookieless, GDPR-compliant Umami analytics to track traffic sources and per-service form
conversions, replacing the client's zero visibility into lead origins.
PROJECTS
LearnFlow - Backend for AI Learning Platform | NestJS, REST API, PostgreSQL, Prisma, Swagger, Docker
● Modelled study topics as a dependency DAG and implemented topological sorting to produce a valid
learning order, with cycle detection rejecting malformed AI output before it reached the database.
● Integrated Google Gemini to generate structured study roadmaps from a subject name, parsing free-form
model output into ordered topics with estimated hours and prerequisite relationships.
● Implemented the SM-2 spaced-repetition algorithm to schedule topic reviews based on user recall quality.
● Structured the API into modular domains (auth, users, subjects, topics, AI) with a layered controller/service
architecture, documented via Swagger.
● Secured the API with JWT auth, route guards, bcrypt hashing and DTO validation.

Telegram Workout Bot | TypeScript, grammY, Jest, PostgreSQL, Prisma, Docker
● Created a Telegram bot for workout tracking with persistent state and with template-based workout logic.
● Designed a normalized relational schema with Prisma ORM and PostgreSQL, including a separate template
system for reusable routines.
● Implemented a workout template engine letting users save, manage, and instantiate predefined training
plans.
● Used Redis for session/state caching and Prisma for data persistence.
● Deployed as a webhook-driven serverless Express endpoint

EDUCATION
BSc in Software Engineering expected 2027
Odesa Polytechnic National University Odesa, Ukraine
Relevant coursework: Databases, Software Testing, Algorithms, Machine Learning.

Languages
Ukrainian (Native), English (B2)