Denys

Denys Diachenko
Senior React.js Developer
8 Years Experience
Intermediate English Level

Professional Summary
Senior Front-End Engineer with 8+ years of commercial experience specializing in React, Next.js, and mod-
ern web ecosystems. Proven track record of architecting scalable web applications, integrating complex
APIs (Twilio, Stripe), and delivering seamless UI/UX. Power user of advanced AI engineering tools (Cursor,
Claude, Copilot), actively leveraging them to automate React component generation, optimize complex state
management, and drastically reduce time-to-market. Passionate about driving business value through clean
architecture and AI-accelerated performance optimization.

Tech Skills

ReactJS Next.js TypeScript TailwindCSS Jest

Laravel Twilio API Redux Sendgrid PostgreSQL

Node.js Stripe PayPal Cursor Claude.ai

Key Achievements
Proficiency in Software Development

- Managed full-cycle software development from requirement analysis and system design to
implementation, automated testing, and CI/CD deployment.
- Engineered highly scalable and maintainable front-end architectures utilizing React and Next.js,
focusing on deep performance optimization and clean code practices.
- Seamlessly integrated complex third-party services including payment gateways (Stripe, PayPal)
and communication APIs (Twilio voice/SMS).
 Collaborative Creativity

- Partnered closely with cross-functional teams to transform complex business requirements into
intuitive, user-centric web interfaces.
- Pioneered the integration of AI tools (Cursor, ChatGPT) into daily development processes, utilizing
them for rapid UI boilerplate generation, automated Jest testing, and complex code refactoring.

Technical Guidance and Mentorship

- Mentored junior and mid-level developers, providing architectural guidance and fostering a culture
of continuous learning and quality assurance.

Education
Master's Degree in Engineering Mechanics

Department of machine design and operation at Ukrainian National Central University
SEP, 2009 - JUL, 2014

Last Projects Engaged
CrewForge HQ

AI-powered local service platform built with Next.js, Supabase, and Twilio. It helps businesses
manage onboarding, capture calls and SMS leads, and publish SEO landing pages that drive direct
customer contact.
Technologies
NextJs, Supabase,Twilio, Google analytics, Stripe

Features
• Developed dynamic, AI-generated SEO service and location pages using Next.js, significantly boosting organic
traffic and customer acquisition.

• Twilio voice and SMS lead capture
• Supabase-backed business onboarding and analytics

Zalow Engineering

Zalow is a global freelancing platform connecting skilled freelancers with companies and clients.
It enables project-based work and offers tools for management, communication, payments, and
professional networking.
Technologies
NextJS, Stripe, Ant.Design, ApiDog,Segment

Features
• Real-time messaging and notifications via WebSockets, with typing indicators, read receipts, and presence status.
• End-to-end project lifecycle: publish projects, manage proposals and offers, track milestones and attachments,
and streamline reviews.

• Secure payments with Stripe: card checkout, invoices, and milestone-based releases, with error handling and
clear transaction history.

• Developed intuitive front-end interfaces for AI-driven platform features, such as smart freelancer-to-client
matching and automated proposal generation, enhancing user engagement and project success rates.

APR, 2024 - APR, 2025

MNTR

A social fitness & meal-tracking mobile app for planning workouts and nutrition. Features posts feed,
chats, friends, subscriptions, goal tracking, wearable stats, momentum score, workout programs,
meal plans, recipes & exercise videos.
Technologies
React Native, Redux, RTK, In-app payments, Terra SDK, Twilio

Features
• Configured ESLint according to the company standards by setting up coding standards, rules, and configurations
for consistent code quality.

• Configured App Center builds for iOS and Android by setting up build pipelines, build triggers, build variants, and
automated tests.

• Configured Rollbar for app errors tracking by integrating the Rollbar SDK, setting up error monitoring, defining
error severity levels, and analyzing error logs.

• Worked on implementing integration with wearable devices such as fitness trackers and smartwatches using
Terra SDK

• Participated actively in daily meetings with the team, contributing insights, updates, and suggestions to drive
project progress.

• Twilio OTP verification, SMS notifications and reminders

James Smith Academy

A holistic fitness app that lets users set and track personal goals, sync wearables via Google Health
and Apple HealthKit, access personalized training, nutrition recipes, instructional videos, in-app
purchases, and real-time trainer chat.
Technologies
React, React Native, Redux, Redux Saga, RTK, SASS, Django Templates, jQuery, PayPal, Stripe, In-app pay-
ments

Features
• Implemented Sentry for comprehensive error tracking and monitoring, enabling real-time identification and
resolution of app issues and performance bottlenecks.

• Worked diligently on bug fixing and optimization of existing features, meticulously identifying and resolving
issues to enhance the overall performance and user experience.

• Skillfully configured Stripe and PayPal payment gateways on the web platform, ensuring seamless and secure
transactions for users, thereby enhancing the platform's e-commerce capabilities.

• Implemented in-app payment systems on the mobile application, enabling users to make purchases and trans-
actions within the app seamlessly, improving user convenience and revenue.
• Integrated Google login functionality across both the app and web platforms, simplifying user authentication
processes and enhancing security measures through Google's robust authentication protocols.

JAN, 2021 - JAN, 2023

An e-commerce auto parts platform

An e-commerce auto parts platform with a custom admin panel integrated with eBay and Amazon
for automated listings, dynamic pricing, inventory sync, and vehicle fitment management. Includes
complex logic for syncing products, prices, and availability.
Technologies
Laravel, MySQL, Guzzle (eBay/Amazon APIs), Redis/Queues, Cron Workers, XML/CSV Parsing, React

Features
• Repricer Engine: Automatically analyzes competitor prices and adjusts our prices dynamically — lowering them
to stay competitive or increasing when we are the only seller.

• Fitment Management System: A system for managing part-to-vehicle compatibility powered by the regularly
refreshed eBay Motors catalog.

• Multichannel Listing: Ability to create and update listings simultaneously on the website, eBay, and Amazon via
API integrations.

• Inventory Sync: Real-time synchronization of stock levels and orders across all sales channels.

APR, 2015 - AUG, 2021