Project on developing a multifunctional browser extension. Features include screenshots, video screen recording, bookmarks, webcam footage, audio recording, page testing (checkers), verifying links used in page development, as well as server and services security checks. Achieved a significant reduction in the time required to build recommendations for errors and UI issues by developing a suite of features, decreasing the process time from potentially hours to just a few minutes.• Using Lighthouse (Google), axe-core (AXE-library), and Observatory (Mozilla) libraries, developed a set of 5 checkers and 2 servers from scratch, based on Express and Socket.IO, to verify the functionality, performance, loading speed, user interface accessibility, and security of web page links.• Developed and implemented a high-performance algorithm for scanning documents, searching for links, and verifying their validity using Cheerio, Axios, Fetch, and Lodash libraries. This resulted in a more than 10-fold reduction in website page processing time, 50% reduction in CPU load, and 4 times decrease in memory usage.• Developed an extension system that allows users to access their data from multiple devices by storing user data in cloud storage, with a built-in data synchronization algorithm and multi-level fault tolerance, using Express and S3.• Designed an intermediate server to protect user data, monitor, and fix errors. Ensured proper data synchronization under conditions with up to 40% packet data loss due to network issues.• Involved in designing and implementing user interfaces as part of a team consisting of 2 additional developers and 2 QA engineers. Authored 5 user manuals for various components for the company's clients.• Fixed an average of 50 bugs per month, ensuring the overall functionality and stability of the system.

Developed specific databases and servers for 7 mobile application projects from start to finish working in teams of 2 to 5 developers. Actively participated in application testing and bug fixing to ensure smooth functionality and optimal performance.For three e-commerce projects• Developed and implemented a database to support the creation of complex product lists, including product sets, groups, and tags, as well as the creation of multifaceted products comprised of various elements, with the capability to apply flexible pricing and various discounts.• Developed a server integrated with the database, enabling product search, order creation and processing, as well as tracking of order statuses, payments, and deliveries to clients, utilizing technologies such as SQL, Express, CORS, Sequelize, and Node.js elements including pg, pg-connection-string, and querystring.Сonnecting cargo owners and carriers projectLectorium project• Created a user registration system for different user types: administrators, moderators, authors, and students. Developed a database access permission system for different users with jsonwebtoken, Passport, Nodemailer, nodemailer-smtp-transport, and SMS-service. The system includes email and phone verification, administrator account moderation, and the capability for additional restrictions if needed.• Organized the storage of user data, lecturers, and lectures, and formulated program lists based on various parameters (payment, interests, new lectures, etc.) using SQL, Express, Sequelize, pg, pg-connection-string, pg-hstore, and querystring.Walks with Animals project Dictionary (Front-end + Back-end) project• In a team of three programmers, developed a mobile application and a database server for learning English.

• Collaborated with a team of five programmers to develop web applications and database servers.• Designed user interfaces emphasizing visual accessibility and clarity while optimizing the number and structure of control elements.• Developed databases for data collection, storage, and processing, and created algorithms to ensure data integrity and accuracy.• Engineered systems for data protection, backup, and recovery to safeguard critical information.• Designed and implemented a client chat system, enabling customers of a trading company to engage in product discussions, share opinions, and create channels and groups for internal communication.• Contributed to a 10% increase in the company's customer base through the successful implementation of the chat system.