getacorn.com - app for parents to help them to search, book and pay children activities. Platform for activities providers to manage schedule, bookings, and payments.Technology stack: Golang, PostgreSQL, ElasticSearch, Docker, Kubernetes, Google Cloud Platform, Nginx, Sentry, Prometheus, TypeScript, React, Redux.- Backend development: Go, microservices, gRPC, databases, search, caching, delayed tasks; external services integration (Google APIs, Auth0, Stripe, MailChimp, etc); TDD: unit testing, integration tests, functional tests; monitoring health and availability.- Architect and develop REST API for mobile apps and web; documentation (OpenAPI); API versioning with backward compatibility.- Deploy services to Kubernetes cluster using Docker containers; implement full CI/CD cycle using GitHub, Circle CI, and Google Cloud Platform.- Admin panel development: typescript, react, redux; participate in public web sites development.- Technical leadership: architecture decisions, managing and teaching a team, code review, hiring.

An online distribution platform for fitness and lifestyle content by creating, editing and sharing individual workouts.Technology stack: Python, MySQL, Google Cloud Platform, Sentry, JavaScript, React, Redux.- Designed and developed backend using Django Python framework.- REST API for mobile apps with versioning, fully documented and tested.- Integration with video uploading and streaming backend.- Integration with Stripe payments and subscriptions.- Admin panel development: javascript, react, redux.

calendar.mail.ru – largest time-management and scheduling calendar service in Russia. Technology stack: Python, C, Lua, Go, PostgreSQL, Nginx, Celery, RabbitMQ, Tarantool, Sentry, Graphite, Grafana.- Designed and developed calendar service from scratch with REST API for web and mobile apps; developed CalDAV server for integration with calendaring software.- Shared calendars between users; shared calendar events between calendars and users; invitations.- Integration with external calendar services APIs (like Google Calendar, MS Exchange).- Developed delayed scheduled notifications service (email, push, text messages, 100kk daily) using Tarantool (NoSQL database with Lua scripting).- Building and using configuration management system.- Tuning software such as Nginx and PostgreSQL to achieve high scalability and networking performance.- Auto-tests; continuous deployment; monitoring health and availability; error handling.- Technical leadership: architecture decisions, team growth, code review, hiring.

e.mail.ru – largest email service in Russia.Technology stack: Perl, C, MySQL, Apache, Nginx, JavaScript, jQuery.- Developed new features for Mail.ru email service with focus on scalability and performance such as ajax web email client with C backend (20kk daily users).- Developed help desk service (50k daily emails average).- Rebuilt system for code and static files deployment (thousands of servers, gigabytes of static files).- Initiated and transferred 10 years old legacy codebase from CVS to Git; teaching a team to work with git.

Educational training online portal.Technology stack: PHP, Perl, Python, C, Delphi, MySQL, Memcached, ActionScript, Flash, JavaScript.- Design, development, and support of web portal and e-shop.- Development of USB drivers and software for the electronic device.- Development of web online multiplayer games with custom control hardware (USB joystick).- People management (employees, freelancers).

Full-cycle of industrial security, fire alarming and firefighting systems development and production.Technology stack: Assembler, C, C++, Delphi.- Hardware and firmware development of industrial security and fire alarm system.- Hardware development of different radio electronic equipment and software for them.