Kostiantyn Tsymbal

Working on Google Cloud

As a Senior Software Engineer at the core team of Fiverr, I lead the development of scalable applications, optimize system performance. Main achievements: - Owned an AI-driven feedback feature using prompt engineering, boosting first orders by 7.3% and gig clicks by 11.4%. - Led the feature from concept to launch, contributing to a subscription that generated 5.9% of the monthly revenue from all programs. - Designed and launched a shared high-performance microservice for seamless LLM integration. - Participated in the on-call rotation.

• Optimized endpoints, reducing response time by 20% using AWS Step Functions, enhancing user experience. • Initiated testing protocols, achieving 40% coverage, improving code reliability. • Led onboarding for new developers, accelerating team integration. • Developed Grafana dashboards for real-time monitoring, integrated alerts with Slack for immediate issue response. • Investigated and identified root causes of system memory leaks, ensuring system stability and performance.

• Implemented a feature for fining dishonest customers, increasing monthly revenue by 7.3%. • Added automatisation to create the most used entity. It reduced commonplace mistakes and time for creation by 34%. • Increased speed of cron job by 10 times by refactoring code and rewriting queries to database. • Migrated the old service to the new architecture of the application. It fixed bugs with database transactions. • Proposed database design updates, significantly reducing development time for some features. • Participated in the onboarding of middle-level developers

• Implemented a feature for history tracking. It was one of the main features to start selling it to enterprise customers. • Reduced execution time of the long task by 41% with multithreading. • Enhanced UI/UX of main page and menu, increasing the number of new subscriptions. • Added the ability to run e2e tests to test all common workflows. The improvement reduced the number of complaints after the release by 9.3%

Skills: MongoDB · E2E · Unit Testing · NestJS · Back-End Web Development · Systems Design · Algorithms · React.js · Data Architecture · Git · Software Architecture · API Development · IT Integration · Linux · Amazon Web Services (AWS) · Data Structures · Databases · Computer Engineering · Business Logic · Amazon S3 · Agile Methodologies · TypeScript · Communication · Microservices · REST APIs · Express.js · PostgreSQL · Docker Products · Continuous Integration and Continuous Delivery (CI/CD) · Integration Testing · Sequelize.js · Full-Stack Development · MySQL · Problem Solving · Object-Oriented Programming (OOP) · Object-Relational Mapping (ORM) · Server Side