Денис

Denys Yakovenko
Front-End Developer | React | Next.js | TypeScript

📞 [open contact info](look above in the "contact info" section)
📧 [open contact info](look above in the "contact info" section)
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🔗 GitHub | LinkedIn | Portfolio
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PROFESSIONAL SUMMARY

Result-driven Software Engineer with 3+ years of production experience delivering
scalable web and mobile solutions. Specialized in the React ecosystem (Next.js, React
Native) combined with robust backend architectures using Node.js/NestJS. Proven
expertise in building internal enterprise tools, custom CRM systems, and high-performance
marketing platforms. Strong focus on code quality, A/B testing implementation, and reducing
technical debt to optimize business operational costs.

TECHNICAL SKILLS

●​ Core Stack: JavaScript (ES6+), TypeScript, React.js, Next.js, React Native, Node.js.
●​ State Management & Data: Redux Toolkit, Zustand, React Query, GraphQL
(Apollo), REST API.
●​ Backend & Architecture: NestJS, Express.js, Microservices, WebSockets, RBAC.
●​ Database: PostgreSQL, MongoDB, Prisma ORM.
●​ Testing & QA: Jest, React Testing Library, Cypress, Playwright.
●​ DevOps & Tools: Docker, CI/CD (GitHub Actions), Webpack, Vite, Vercel, GA4,
Looker Studio.

WORK EXPERIENCE

Software Engineer (Web & Mobile) ZBL | Media Buying & Tech Product | Remote |
08/2025 – Present

Spearheading the technical development of internal ecosystems and mobile infrastructure,
directly impacting the efficiency of media buying operations.

●​ Cross-Platform Mobile Architecture: Designed and built a scalable mobile
application foundation using React Native and TypeScript, ensuring 99% code
sharing between platforms.
●​ Enterprise CRM System: Engineered a high-performance custom CRM
(React/NestJS) that automated complex data collection workflows, resulting in a 40%
reduction in manual reporting time for the operational team.
 ●​ Traffic Optimization Engine: Developed a custom A/B testing tool integrated with
marketing funnels, enabling precise ad campaign optimization and saving significant
budget on ineffective traffic sources.
●​ Data Visualization: implemented real-time analytics dashboards integrating GA4
and Looker Studio, providing stakeholders with actionable insights and reducing
decision-making time.

Full Stack Developer Skyads | Performance Marketing | Remote | 02/2025 – 07/2025

Focused on system stability, high-load feature implementation, and legacy modernization for
a fast-paced marketing platform.

●​ High-Load System Engineering: Developed and deployed critical platform features
using Next.js and Node.js, capable of handling high-volume traffic spikes during
marketing campaigns.
●​ Legacy Modernization: Conducted a comprehensive audit and refactoring of the
legacy codebase, reducing technical debt by 20% and significantly improving
application stability and maintainability.
●​ Database Optimization: Collaborated with the product team to translate complex
business logic into efficient technical solutions using MongoDB aggregations and
optimized schemas.
●​ End-to-End Testing: Introduced automated testing workflows (Cypress/Jest),
reducing regression bugs in production releases by 30%.

Independent Software Engineer (Freelance) Remote | 10/2021 – until now (part-time)

●​ Delivered custom CMS and E-commerce dashboards for international clients using
the MERN stack and Next.js.
●​ Architected secure admin panels with Role-Based Access Control (RBAC) using
NestJS and PostgreSQL.
●​ Set up CI/CD pipelines to automate deployment processes, ensuring quick
time-to-market for client projects.

EDUCATION Bachelor of Software Engineering European University | Kyiv, Ukraine |
09/2020 – 05/2023

LANGUAGES English: Advanced (C1) | Ukrainian: Native | Polish: Intermediate