● Designing microservice architecture (Node.js, Nest.js, TypeScript, Redis). ● Designing WebSocket integrations with cryptocurrency exchanges (Binance API, Bitfinex API). ● Database design and query optimization (PostgreSQL, TypeORM). ● Implementation of CQRS architecture. RESTful API development (Express.js, OpenAPI/Swagger). ● RESTful API development (Express.js, OpenAPI/Swagger). ● Frontend development (React.js, TypeScript, Redux Toolkit, Material UI). ● Containerization and orchestration (Docker, Docker Compose). ● CI/CD automation (GitLab CI/CD, Docker Registry). ● Agile/Scrum processes (Planning, Code Review, Sprint Management). Key Achievements: ● Exchange integration architecture (WebSocket, BullMQ, Adapter Pattern): ● Integration with 10 crypto exchanges (Binance, Bitfinex, etc.). ● Optimization of development time: from 14 to 3 days per new exchange. ● Standardization of the integration process for middle developers. Microservice architecture (Node.js, Docker): ● Modular system on Express.js with TypeScript. ● Autoscaling via Docker Swarm. ● Independent component deploy (Docker Compose, GitLab CI/CD). DevOps optimization: ● Test automation (Jest, Supertest). ● Continuous Deployment (GitLab CI/CD, Docker). ● API documentation (Swagger/OpenAPI). ● Bi-weekly releases (Agile/Scrum). Frontend development (React.js): ● UI Kit library (30+ React components, Storybook). ● State management (Redux Toolkit, TypeScript). ● Performance optimization (React.memo, useCallback, Webpack).

Enterprise analytics platform and embeddable advertising video player. Analytics platform (React, TypeScript). Designing a high-performance frontend architecture: ● Interactive widget system (D3.js, Chart.js). ● Complex table views (AG Grid Enterprise). ● Report generation (PDF, Excel). ● Achieving maximum performance (Lighthouse 100/100). ● Microfrontends and modular architecture. ● Optimizing development costs by 100% through effective delegation. Enterprise UI Kit (React, Storybook). Enterprise component library development: ● Complex tables with customization (sorting, filtering, grouping). ● Specialized forms with validation. Analytical components (graphs, charts, dashboards). ● Unification of the design system for all company projects. ● Storybook documentation and use cases. Advertising Video Player. Creating a modular architecture: ● Isolated playback core (HTML5 Video API). ● System of customizable skins. ● Integration of VAST/VPAID advertising protocols. ● Playlist and streaming support. ● Plugin architecture to extend functionality. ● Cross-browser compatibility and style isolation. Leadership and team management. Team development (4 frontend developers): ● Conducting technical interviews and onboarding. ● Code review and implementation of best practices. ● Agile planning and task estimation. ● 100% retention rate and career development of employees. Mentoring and development: ● Technical mentoring (React, TypeScript, architecture). ● Soft skills development. ● Burnout prevention. ● Working with motivation and professional growth. Process optimization. Implementing engineering practices: ● Git Flow and code review standards. ● CI/CD automation (Jest, Cypress). ● Component-Driven Development (Storybook). ● Agile/Scrum processes.

Design and development of highly loaded web applications with complex business logic. Development and support of REST APIs and GraphQL endpoints. ● Database architecture design and query optimization. ● Development of bots for messengers with integration of external services. ● Turnkey MVP development for startups. ● Technical consulting of the team on development issues. ● Managing the full cycle of project development. ● Drafting technical documentation and TORs. Key accomplishments: Architectural decisions and optimization: ● Designed and implemented a microservice architecture that reduced the time to deploy new features by 60% and increased system fault tolerance to 99.9%. SQL queries and database structure were optimized, which resulted in 75% speedup of key operations (from 3 sec to 0.7 sec) under 1000+ RPS load. ● Implemented a caching system using Redis, reducing database load by 40% and API response time by 65%. Development and Scaling: ● Designed and implemented a real-time communication component via WebSocket, handling up to 50,000 simultaneous connections with <100ms latency. ● Created a library of 25+ overused React components, reducing development time for new interfaces by 40%. ● Implemented a backend for Telegram bots processing 100,000+ messages per day. Optimization of development processes: ● Implemented an automated testing system (unit + e2e), increasing code coverage from 40% to 85% and reducing production bugs by 70%. ● A GitLab-based CI/CD system was developed and implemented, reducing the deployment time from 40 minutes to 12 minutes. ● Created a system for automatic generation of API documentation, saving the team 20+ hours per month on documentation support.

Team and Process Management: ● Leading a team of 6+ developers. ● Estimating and planning project work. ● Allocating tasks based on team competencies. ● Conducting regular 1-on-1 meetings with team members. ● Organizing and conducting technical interviews. Technical Leadership: ● Conducting code reviews and architectural reviews. ● Mentoring and providing technical advice to the team. ● Participating in the development of critical components. ● Conducting technical research (R&D). ● Quality control of code and technical debt. Process development: ● Training the team and implementing modern development practices. ● Standardization of testing and work acceptance processes. ● Optimization of CI/CD processes. Key accomplishments: Modernized development processes: ● Implemented modern project build on Webpack, speeding up build time by 70% and reducing the size of the bundle by 45%. ● Developed and implemented coding standards, reducing code review time by 30%. ● Increased unit test coverage from 20% to 75% in 6 months. ● Implemented automated e2e tests, reducing regression testing time from 2 days to 4 hours. Team Development: ● Conducted 25+ training workshops on ES6+, OOP, and functional programming. ● Created a knowledge base of 10+ white papers and guidelines. ● Reduced team turnover by 40% thanks to mentoring system. ● Increased speed of onboarding new developers from 3 weeks to 1 week. Optimization of project work: ● Successfully completed 12 projects on time and on budget. ● Average time from development start to release reduced by 35%. ● Number of critical bugs in production reduced by 60%. ● Customer satisfaction increased from 70% to 92% (based on surveys). Technical innovations: ● A unified library for working with map services (Leaflet.js, Google Maps, Yandex Maps) was developed. ● A set of reusable components, customizable components was created, which accelerated the development of new projects by 40%.

Information systems for the public sector. Key accomplishments: Architecture modernization (React, Redux): Successful migration from jQuery to modern stack: ● Migration from Backbone.js to React + Redux. ● Implementing a component-based approach. ● Implementing unit testing (Jest). ● Optimization of application performance. ● Reduction of support and debugging time by 40%. Realization of interaction with GosIS: ● Authorization via ESIA (Gosudservices). ● Integration with SMEV. ● Work with regional databases (RDB). ● Compliance with information security requirements. ● Documentation of integration solutions. Designing and improving systems: ● Database architecture (MS SQL Server). ● Optimization of SQL queries. ● Implementing SOLID principles. ● Application of design patterns. ● Dependency Injection implementation. ● Optimization of teamwork: ● Implementing effective code review. ● Reducing the number of bugfixes. ● Agile/Scrum methodologies. ● Sprint planning. ● Conducting project meetings. Team Development: ● React and Redux training. ● Implementing best practices. ● SOLID architectural principles. ● Code review practices. ● Technical workshops. From Junior to Team Lead: ● Developing internal projects from scratch. ● Mastering architectural patterns. ● Learning design principles. ● Developing technical leadership skills. ● Participating in architectural decision making.