Yaroslav Zozulya

Summary

Fullstack developer with 4+ years of experience building production web applications. Currently building Web3 platform APIs with NestJS, PostgreSQL, Redis, and Docker. Hands-on experience with DDD architecture, authentication systems (JWT, 2FA, OAuth2), blockchain integrations, and performance optimization. Comfortable owning features end-to-end and working independently in fast-paced teams.

Experience

Backend Developer · Rod Software Dec 2025 – Present

Building REST API for a Web3 platform processing blockchain transactions across Ethereum, Solana, Tron, Polygon and other networks.
Designed and implemented modular DDD architecture in NestJS — clean separation of domain, application, and infrastructure layers.
Developed multi-strategy auth system: JWT with refresh rotation, 2FA (TOTP), Google OAuth2, API keys, and role-based access control.
Integrated PostgreSQL (TypeORM), Redis for caching and rate limiting, BullMQ for async job processing.
Maintained Docker / Docker Compose setup for local development and production deployments.

Fullstack Developer · DevIT Group 2024 - 2025

Reduced API filter response time from ~5s to ~1s by replacing direct Strapi queries with a Redis caching layer via custom Express middleware.
Designed data sync pipeline: Strapi → Redis on app startup; all filtering served from in-memory cache without hitting the CMS.
Extended Docker Compose infrastructure, added new services to the development environment.
Developed new pages and features on Next.js frontend.

Fullstack Mentor · GoIT 2022 – 2024

Conducted lectures on HTML/CSS, JavaScript, and Node.js for fullstack development course.
Reviewed student code, provided technical feedback, supported 100+ students through the learning process.

Fullstack Developer · Freelance (Side projects) 2022 – Present

Built e-commerce and business web applications for clients using Next.js, Strapi, PostgreSQL, MongoDB, Railway, and Cloudflare.

Frontend Developer · Aweb.ru 2021 – 2022

Developed UI components and mobile-responsive layouts; worked with various CMS platforms.

Project Manager · Proxy-sale.com 2018 – 2021

Wrote technical specifications, managed bug tracking and task delegation across development teams for proxysale.com and proxy-seller.com.

Technical Skills

Languages TypeScript, JavaScript Backend NestJS, Express, Node.js, REST API Frontend Next.js, React, Tailwind CSS, SASS Databases PostgreSQL, MongoDB, Redis ORM / ODM TypeORM, Mongoose Auth JWT, OAuth2 (Google), 2FA (TOTP), RBAC, API Keys Testing Jest, Supertest, @nestjs/testing, unit & e2e Infrastructure Docker, Docker Compose, Railway, Cloudflare CI/CD GitHub Actions Other BullMQ, Strapi, Git, Web3 integrations