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Hi, I’m Illia Lazarenko, a full-stack developer with 3+ years of experience in React, Next.js, TypeScript, and Node.js. I focus on building CRM/ERP solutions, automation workflows, and API integrations to improve efficiency and scalability. Most recently I led production-critical features, conducted code reviews and technical interviews, and introduced testing and quality standards that reduced production bugs and accelerated development.…Hi, I’m Illia Lazarenko, a full-stack developer with 3+ years of experience in React, Next.js, TypeScript, and Node.js. I focus on building CRM/ERP solutions, automation workflows, and API integrations to improve efficiency and scalability. Most recently I led production-critical features, conducted code reviews and technical interviews, and introduced testing and quality standards that reduced production bugs and accelerated development.

Illia Lazarenko

Full Stack Developer, Web Developer, Front-End Developer, +2

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Hi, I’m Illia Lazarenko, a full-stack developer with 3+ years of experience in React, Next.js, TypeScript, and Node.js. I focus on building CRM/ERP solutions, automation workflows, and API integrations to improve efficiency and scalability. Most recently I led production-critical features, conducted code reviews and technical interviews, and introduced testing and quality standards that reduced production bugs and accelerated development.…Hi, I’m Illia Lazarenko, a full-stack developer with 3+ years of experience in React, Next.js, TypeScript, and Node.js. I focus on building CRM/ERP solutions, automation workflows, and API integrations to improve efficiency and scalability. Most recently I led production-critical features, conducted code reviews and technical interviews, and introduced testing and quality standards that reduced production bugs and accelerated development.

Available to hire

Hi, I’m Illia Lazarenko, a full-stack developer with 3+ years of experience in React, Next.js, TypeScript, and Node.js. I focus on building CRM/ERP solutions, automation workflows, and API integrations to improve efficiency and scalability.

Most recently I led production-critical features, conducted code reviews and technical interviews, and introduced testing and quality standards that reduced production bugs and accelerated development.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Language

English

Advanced

German

Fluent

Ukrainian

Fluent

Russian

Fluent

Work Experience

Full-Stack Developer at photovate GmbH

November 1, 2024 - November 1, 2025

Independent end-to-end development of 4 business-critical modules from scratch (authentication, appointment management, contact management, products) for the internal SaaS platform. Conducted 30+ code reviews and technical frontend interviews for candidate evaluation. Implemented testing best practices (Jest, Bun) and code quality standards, reducing production bugs by 60% within 6 months.

Full-Stack Developer (Node.js / React) at Traffic Devils

March 1, 2023 - June 1, 2024

Independent end-to-end development of a CRM platform for digital marketing (B2B SaaS): database design (PostgreSQL/MongoDB, 15+ tables), RESTful API (Node.js, 30+ endpoints), React frontend (5 modules), containerization with Docker. Performance optimization: 4x faster message delivery for the Telegram bot (20,000+ users) through DB query refactoring and optimized message flow while respecting API rate limits. Process automation: 90% time reduction for Facebook ad creation (10 →1 min) through Selenium optimization — enabled faster campaign launches and increased throughput. UX/UI improvements of the Telegram bot with extended functionalities, increasing user engagement rate by 35%. Integration of OneSignal push notifications and Facebook Ads API with authentication, throttling, and versioning for long-term stability.

Full-Stack Developer (Self-Employed) at Self-Employed / Freelance

April 1, 2022 - February 1, 2023

Full-cycle development of web applications and CRM systems for international clients: architecture design, implementation, production deployment with Docker (React, Node.js/Express). Building modular applications with RESTful API design; database design and optimization (MySQL, PostgreSQL, MongoDB) with a focus on query performance and scalability. Direct client communication: requirements analysis, technical consulting, iterative development and project management.