Олексій

Oleksii Chalenko
Software Engineer

[відкрити контакти](див. вище в блоці «контактна інформація») [відкрити контакти](див. вище в блоці «контактна інформація») Kharkiv, Ukraine

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About Me

Backend-focused Full-stack Developer with 3+ years of commercial experience building secure,
integration-heavy web applications. Specialize in TypeScript, Node.js, NestJS, and React, with
hands-on experience in PostgreSQL, Redis, payment integrations, authentication, asynchronous
processing, and REST APIs. Focused on reliable systems, clean architecture, and maintainable
code.

Professional Experience

Confidential Client Projects (NDA) 09/2025 – Present
Backend / Full Stack Developer Remote

● Developed backend services and REST APIs using TypeScript, Node.js, NestJS, PostgreSQL,
Redis, Docker, and AWS services.
● Implemented reliable external API and webhook workflows with signature validation,
idempotency, retries, background processing, and audit-friendly state transitions.
● Integrated Stripe payment workflows and implemented TOTP-based two-factor
authentication compatible with Google Authenticator.
● Developed backend modules for a Telegram gaming platform using NestJS, Prisma,
PostgreSQL, and Redis, including matchmaking, background workers, player progression,
in-app purchases, and signed payment callbacks.
● Created and maintained database schemas, migrations, API documentation, automated
tests, and local development environments.

Advocate Association “Zahist” 09/2022 – 09/2025
Full Stack Developer Remote

● Designed and implemented RESTful APIs with Node.js/Express, ensuring secure
authentication and scalable architecture.
● Integrated OpenAI assistant to enhance user interaction and automate parts of
the workflow.
● Optimized database queries in MongoDB to improve performance and reduce
response time.
● Built dynamic user interfaces with React and managed state using Redux Toolkit.
Skills

Backend: Node.js, NestJS, Express, TypeScript, REST APIs, Webhooks

Databases: PostgreSQL, MySQL, MongoDB, Prisma, TypeORM, Sequelize, Mongoose

Async & Infrastructure: Redis, BullMQ, Docker, AWS, Git

Security & Payments: JWT, Refresh Tokens, TOTP / Google Authenticator, Stripe, Tap

Quality & Documentation: Jest, Swagger / OpenAPI, Postman, Sentry

Frontend: React, Redux Toolkit, Tailwind CSS, Ant Design

Education

Kharkiv National University of Radio Electronics
Bachelor degree, Software Engineering Master's degree, Computer Science
2019-2023 2023-2025