Tomáš Tibenský

- reducing AWS costs for multiple projects by up to 50% by optimizing used resources, creating infrastructure with predictable resource allocations, and applying AWS Savings Plans
- achieving 99.99% long-term uptime on a Rails backend platform by adopting the latest development best practices, having >90% test coverage, and creating scalable infrastructure with high availability and fully automated CI/CD
- reducing response times of the REST API endpoints by up to 90% by removing n+1 queries, adding and optimizing indexes in Postgresql (full-text search, where conditions on a JSONB column), and adding views caching (JBuilder) in Redis with different variants (list, detail) for certain entities indefinitely and clearing the cache when the underlying data has changed
- ensured all application logs were valid JSON for search/filter purposes and added requests/Sidekiq contextual information such as metrics, response body size, number of SQL queries, request length, exception stack trace, user ID, and other useful data to every warning and error level log for solving issues more effectively
- created AWS CloudWatch dashboards and Log Insights queries that centralize logs from EC2 instances, ECS Fargate Docker containers, WAF (firewall), and other sources, to use weekly to spot potential bugs, anomalies, performance issues, and security threats
- led a Rails backend team on a US project, collaborating on a software architecture with 2 more architects, responsible for creating a technical roadmap, discussing business needs with the client, and proposing viable software solutions that are deliverable quickly and can be built upon and extended later
- mentoring a person from entry-level to software engineer able to take over responsibilities for a project Rails backend platform, production infrastructure, and CI/CD after 3 years

Key experiences/achievements:
- being successful in leading a Slovakia-based team for 4 years and delivering software solutions for a UK-based client
- my first mentoring of a junior developer person who later took over the project I was originally leading
- being successful in setting up my first Docker-based infrastructure in AWS, CI/CD with an emphasis on performance, scalability, stability and high availability

As a seasoned software developer with over 7 years of experience in the field, I have a strong background in developing large backend and web applications, as well as database systems. Throughout my career, I have taken on various leadership roles, including Lead Developer and DevOps, where I was responsible for the code quality, continuous integration and deployments, and production environment uptime for high-traffic web applications such as https://www.joynup.net and http://roxhillmedia.com.

My expertise in using agile software development methods, including Scrum, has allowed me to effectively plan and manage projects, ensuring that milestones are met and delivered on time. I am always striving to stay current with industry trends and best practices, and I have taken an active role in promoting and implementing coding best practices within my teams.

In this role, I utilized a variety of technologies, including PHP >=7.1.x, docker, MySQL, Doctrine, Elasticsearch, Redis, Nginx, Apache 2.x, and Linux, to develop high-quality and scalable applications. I also had the responsibility of managing the applications running in AWS, utilizing services such as AWS ECS, CloudFormation, Ansible, and others.

My technical expertise and leadership experience make me a valuable asset to any organization and I am eager to continue my growth and development in the industry.

I brought my passion for software development to my first role at Ecopress (now MAFRA Slovakia). During my time at the company, I served as a key member of the development team, assisting with the development of several high-traffic Drupal sites including the economic newspaper portal, http://hnonline.sk, http://erun.sk, http://strategie.sk, and http://hnclub.sk.

My expertise in Drupal non-contributed module development allowed me to provide valuable contributions to the company, helping to improve the functionality and usability of the sites. With a solid understanding of PHP 5.2.x & 5.3.x, HTML/XHTML, CSS, MySQL, Apache 2.x, Nginx, Linux, APC 3.x, Drupal 6.x & 7.x, AJAX, Javascript, and JQuery, I was able to develop robust and scalable solutions to meet the needs of the company.

Overall, my ability to quickly adapt to new technologies and my passion for software development made me a valuable asset to the team at Ecopress. I am grateful for the opportunities and experiences I gained during my time at the company and I look forward to continuing to grow and develop as a software developer.