Viktor – React, Node.js, OpenAI API

AI-powered CRM and workflow automation platform for direct sales and social selling teams, leveraging machine learning to optimize customer engagement through intelligent task prioritization, churn prediction, and automated daily action recommendations serving thousands of sales consultants.

• Engineered a system with a RAG functionality to build user profiles, make intelligent introductions, expand and edit profiles through ongoing conversation, and reach out for sales
• Built internal dashboard featuring analytics, performance metrics, and visualized activity, enabling the team to track conversion and engagement
• Implemented scalable backend for managing user profiles, companies, clustering employees to the company, integrating RAG and AI, and automated follow-up workflows
• Integrated AI capabilities using OpenAI API to tailor sales introduction and messaging, matching needs to capabilities, reaching out to customers and doing follow-ups
• Implemented payment gateway integration to collect payments and built the credit system to provide access to the system’s features

Europe's leading online travel booking system serving millions of users across multiple markets. The system supports comprehensive booking infrastructure with package holidays, flights, hotels, car rentals, and excursions with real-time availability management and dynamic pricing across 50+ destinations worldwide.

• Architected scalable microservices handling 10M+ monthly booking transactions with 99.9% uptime across multi-region deployments
• Engineered inventory synchronization system integrating third-party APIs (airlines, hotels, payments) with low response times
• Designed and implemented user account management system supporting loyalty program with personalized recommendation, preferences, and multi-device session handling
• Built responsive, multi-language booking flow with A/B testing that improved conversion rates through optimized experience and checkout flow

A high-traffic sports betting and online casino platform serving the Indian market with 50+ sports markets. It features real-time betting engine with dynamic odds calculation, live streams, and comprehensive payment processing with multiple Indian payment methods including UPI, cryptocurrency, and e-wallets.

• Engineered real-time functionality support for the betting infrastructure from scratch
• Built payment orchestration system integrating payment gateway with KYC verification workflows
• Built core features and UI/UX for the cross-platform mobile application using React Native
• Implemented account management features, including wallet balancing, transaction history, and multi-currency support

A payment processing solution that allows managing split payments, multi-currency wallets, automated payments, and escrow wallets. It empowers online platforms and marketplaces to seamlessly hold, manage, and distribute funds in real time, with full automation and compliance.

• Implemented a file upload feature for CSV files, enhancing data interoperability and efficiency, and providing validation and handling of malformed files
• Developed a custom library for the intelligent import of CSV and Excel files, leveraging the xlsx library to streamline data processing and integration
• Engineered a robust functionality for exporting spreadsheet data to XML, CVS, and Excel formats, ensuring compatibility and ease of data exchange across different platforms
• Refactored existing codebase and significantly increased type coverage to ensure data accuracy and integrity, leading to an improvement in the reliability of the system and development speeds

B2B/B2C marketplace for construction materials and home improvement products, connecting 5,000+ suppliers with contractors and consumers. Supports comprehensive multi-vendor platform with advanced product comparison, intelligent filtering, and supplier management systems.

• Implemented API and UI/UX of the platform’s new features based on requirements and designs
• Implemented initial version of the full-text search using Elasticsearch
• Built integration with additional shipping provider, making the API and frontend more generic to support different providers
• Implemented comprehensive vendor analytics dashboard with sales reporting, inventory insights, and performance metrics

Ukraine's leading hotel booking platform aggregating 4,685+ accommodation properties nationwide with real-time availability, pricing, and reservation management.

• Built a inventory synchronization feature for a reservation management system
• Enhanced data search and filtering enabling users to query across multiple parameters
• Implemented client-side B2B portal for corporate clients to drive marketing and retention