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Backend Engineer with commercial experience designing and developing scalable backend
systems and modern web applications using Node.js, NestJS and TypeScript.

Experienced in building RESTful APIs, authentication and authorization systems, SQL and
NoSQL databases, Docker-based deployments and AI-powered integrations.

Worked across product development, software outsourcing and freelance projects,
delivering production-ready software from architecture design to deployment.

Kostanda Currently pursuing a Master's Degree in Computer Science while continuously expanding
expertise in distributed systems, cloud technologies and scalable backend architecture.
Daniil
Backend Engineer | Node.js • Experience
NestJS • TypeScript
SQUAD Remote
[open contact info](look above in the "contact info" section) Backend Engineer Jul 2025 — Jan 2026
[open contact info](look above in the "contact info" section) Software development company delivering modern web solutions for commercial clients.
Vienna, Austria
• Developed and delivered new features for a commercial SaaS platform based on business
requirements and product roadmap.
Technical Skills • Designed scalable backend services using NestJS and TypeScript.
Backend Development
• Optimized application performance and database queries to improve system scalability.
Node.js / NestJS / TypeScript /
Express.js / JavaScript • Built reusable RESTful APIs supporting frontend applications and business workflows.

• Implemented business logic with a strong focus on maintainability and scalability.
Databases
PostgreSQL / MongoDB / MySQL / • Designed and optimized PostgreSQL database schemas and complex SQL queries.
MariaDB • Improved application stability by applying Clean Architecture and SOLID principles.
ORM / ODM
Yellow DuckCoders Remote
TypeORM / Prisma / Sequelize /
Backend Engineer Jan 2025 — Jun 2025
Mongoose
Software development company specializing in modern web applications and backend
API Development & Security solutions.
REST API / GraphQL / JWT /
• Designed and developed backend modules for modern web applications using NestJS.
OAuth2 / Swagger / OpenAPI
• Built secure authentication and authorization using JWT and OAuth2.
DevOps & Deployment
• Developed reusable RESTful APIs consumed by frontend applications.
Docker / Docker Compose / Nginx
/ PM2 • Designed relational database models using MySQL and TypeORM.

Redis & Caching • Configured Docker-based development environments.
Redis / Caching / Pub/Sub / • Generated and maintained API documentation with Swagger / OpenAPI.
Performance
• Wrote clean, maintainable and well-tested backend code following SOLID principles.
Frontend Development
• Improved backend performance through optimized business logic and database interactions.
React / Next.js / Vue.js / Tailwind
• Participated in architecture discussions and maintained code quality through peer reviews.
CSS / Bootstrap / HTML / CSS

Version Control Freelance Remote
Git / GitHub / GitFlow Fullstack Engineer 2023 – Present
Backend development for startups and commercial client projects.
Software Architecture
Clean Architecture / SOLID • Developed scalable backend systems from scratch using Node.js and NestJS.
/ Design Patterns / Modular • Built RESTful APIs and integrated third-party services.
Architecture
• Integrated AI-powered functionality using OpenAI APIs.
AI Integration
• Designed SQL and NoSQL database schemas for different business domains.
OpenAI API / LLM / AI
Automation • Implemented Redis caching to improve application performance.
Profiles • Configured Dockerized production environments using Docker Compose, Nginx and PM2.

GitHub • Worked directly with clients, estimated development effort and delivered production-ready
Giggbit software.

LinkedIn • Maintained deployed applications and implemented new features based on customer
feedback.
kostanda-daniil

Languages Projects
English AI Crypto Portfolio Tracker 2026
B2 – Upper-Intermediate • Designed scalable backend architecture.
German • Developed RESTful APIs.
B2 – Upper-Intermediate
• Integrated OpenAI API.
Ukrainian
• Implemented JWT authentication.
Native
• Dockerized the application.
Russian
Tech Stack:
Native
Node.js • NestJS • TypeScript • MySQL • Docker

Project Management Platform 2024
Backend platform inspired by Trello for project and task management.

• Built RESTful APIs.

• Implemented JWT & Google OAuth2.

• Developed task management modules.

• Generated Swagger documentation.

• Configured Docker environment.

Tech Stack:

NestJS • TypeScript • MySQL • TypeORM • Docker • JWT • OAuth2 • Swagger

AI Business Platform 2025
Commercial backend platform integrating AI-powered automation into business workflows.

• Designed backend architecture.

• Integrated OpenAI APIs.

• Implemented Redis caching.

• Developed RESTful APIs.

• Configured production deployment.

Node.js • NestJS • PostgreSQL • Redis • Docker • OpenAI API

Education
Odessa Polytechnic National University Master of Science (M.Sc.)
Computer Science Odesa, Ukraine • Sep 2025 – Present
Pursuing a Master's degree in Computer Science with a focus on distributed systems,
software engineering, cloud computing and artificial intelligence. Continuously expanding
expertise in scalable backend architectures and modern software development.

Odessa Technology University "IT STEP" Bachelor of Science (B.Sc.)
Computer Science Odesa, Ukraine • Sep 2021 – Jun 2025
Completed a Bachelor's degree in Computer Science with a strong foundation in software
engineering, backend development, databases, algorithms and modern web technologies.