Personal information hidden

DANIIL KOSTANDA
FULLSTACK / BACKEND DEVELOPER

Vienna, Austria | [open contact info](look above in the "contact info" section) | github.com/Giggbit | LinkedIn
WhatsApp [open contact info](look above in the "contact info" section) | Telegram @Giggbit

TECHNICAL SKILLS PROFILE
BACKEND Fullstack Developer with 3+ years of freelance and commercial experience building responsive frontend
JavaScript, TypeScript, Node.js, NestJS, interfaces, REST APIs and data-driven services. Strong in React, Next.js, Node.js, NestJS and
Express.js TypeScript, with hands-on experience in SQL databases, Docker, authentication, caching and AI
FRONTEND integrations.
React, Next.js, Vue.js, Angular, HTML,
CSS, Tailwind CSS EXPERIENCE
DATABASES
PostgreSQL, MySQL, MariaDB, FULLSTACK DEVELOPER Rariran
MongoDB, Redis Mar 2026 - Jul 2026 | Remote
ORM / ODM Existing product flows required coordinated frontend and backend changes, delivered 7+ end-to-end
Prisma, TypeORM, Sequelize, Mongoose features using React, Node.js and TypeScript, reducing average feature delivery time by
API AND SECURITY approximately 20%.
REST API, GraphQL, WebSockets, JWT, Repeated data requests increased server load and slowed user-facing screens, introduced Redis
OAuth2, Swagger / OpenAPI caching with controlled invalidation, reducing average API response time by approximately 35%.
Production defects affected the UI, API and database layers, identified root causes and resolved 20+
DEVOPS AND TOOLS
issues, reducing recurring bug reports by approximately 30%.
Docker, Docker Compose, Git, GitHub,
CI/CD, Nginx, PM2, OpenAI API FULLSTACK DEVELOPER SQUAD
Oct 2025 - Apr 2026 | Remote
EDUCATION Product requirements spanned both UI and backend workflows, built Next.js interfaces and connected
them to modular NestJS REST APIs, delivering complete SaaS user journeys.
M.Sc. Computer Science Data-heavy pages caused slow responses, optimized PostgreSQL queries and frontend data loading,
Odesa Polytechnic National University improving application responsiveness and scalability.
2025 - Present Duplicated logic made feature changes harder, introduced reusable UI components and modular
TypeScript services, reducing coupling and simplifying maintenance.
B.Sc. Computer Science
IT STEP University FULLSTACK DEVELOPER Yellow DuckCoders
2021 - 2025 Jan 2025 - Jun 2025 | Remote
Frontend integration was slowed by inconsistent endpoints, built React interfaces and NestJS
LANGUAGES modules with Swagger / OpenAPI contracts, making UI-to-API integration predictable.
Protected user flows required consistent client and server security, implemented validated forms,
English - C1 JWT / OAuth2 authentication and route protection, securing access to user data.
German - B2 Development environments and data models differed across setups, standardized MySQL /
TypeORM schemas and Docker configuration, reducing setup friction and inconsistencies.
Ukrainian - Native
Russian - Native FULLSTACK DEVELOPER Independent Projects
2023 - Present | Remote
Clients needed complete products rather than isolated features, delivered responsive React / Next.js
interfaces, NestJS services and SQL schemas from requirements through deployment.
External APIs and repeated requests complicated user workflows, integrated OpenAI and third-party
APIs with Redis caching, enabling automation and faster repeated operations.
Post-release feedback required coordinated changes across the stack, maintained Dockerized
applications and shipped frontend and backend fixes, keeping features stable as requirements
evolved.

SELECTED PROJECTS
CRYPTO PORTFOLIO TRACKER Backend | Frontend
Portfolio analytics with JWT/RBAC, transaction and PnL logic, live prices and AI insights.
NestJS, Next.js, TypeScript, PostgreSQL, Prisma, Docker, OpenAI API
QUIZ BUILDER GitHub
Fullstack quiz application with dynamic forms, nested data and client/server validation.
NestJS, Next.js, React, TypeScript, PostgreSQL, Prisma, Docker, Zod