Mariusz – Ruby on Rails, Ruby, DevOps

All-around e-commerce operation selling products from the Health and Beauty segment. All internal systems and e-commerce platforms were written in Ruby on Rails.

1. Took leadership of all technical operations and hired over 10 developers.
2. Re-architected the entire engineering operation from the ground up and effectively managed the engineering team with regular one-on-one meetings, retrospectives, and 360 reviews.
3. Improved the developer experience by creating a fully automated Docker Compose setup spanning all company Ruby on Rails microservices. This reduced the onboarding process for new hires from weeks to hours.
4. Upgraded the Ruby version on all company services to 3.4.x and the Ruby on Rails version from 6.1.x to 8.0.2.
5. Performed various upgrades of dependencies and other services, including the PostgreSQL upgrade from 12 to 16.
6. Migrated legacy jQuery and React frontend code into the modern Hotwire stack (Turbo, StimulusJS).
7. Led all technical operations and actively participated in most development and infrastructure tasks, performing various API integrations with external platforms.
8. Created internal services for back-office workers and media buyers, effectively improving company processes by an order of magnitude.

It offers physiotherapists a range of tools to create customised home exercise programs. Easy-to-follow videos, pain tracking, and progress monitoring support adherence, all designed to boost engagement and completion rates.

1. Helped to hire 30 engineers (Ruby developers, mobile, and DevOps).
2. Was responsible for taking over the codebase and building the technical part of the new development process.
3. Migrated the monolith CI pipeline from a GitLab server instance that was self-hosted at the software house headquarters to CircleCI.
4. Participated in the organization of multiple company off-site meetings for the engineering team.
5. Upgraded the Ruby version from 2.5.x to 3.1.x and Ruby on Rails monolith from version 5.0.x to 6.1.x.
6. Did a series of performance improvements on the database layer, which led to a significant reduction in infrastructure costs (halving the cost of RDS across all company instances).
7. Was responsible for creating and shaping the on-call and incident management processes within the new team.
8. Built an internal CLI tool in Ruby to manage those environments and automate some day-to-day tasks.
9. Led an effort to build an internal customer acquisition tool, which allowed the marketing team to better optimize their efforts without sharing customer data with any third-party analytics providers.

E-Commerce division at an undisclosed Fortune 500 company

1. Focused on implementing integrations with external partners and payment systems (Stripe).
2. Started an effort to introduce a fully working Docker Compose setup.
3. Led the effort to improve the general developer experience. This included improving the speed and costs of the CI system, unifying the coding style, and introducing various automatic checks around the codebase.
4. Upgraded the Ruby and Ruby on Rails versions used by company applications, improved the quality of the test suite, and enhanced overall test coverage.

All-around e-commerce operation selling products from the Health and Beauty segment. All internal systems and e-commerce platforms were written in Ruby on Rails.

1. Was a "first hired employee," overseeing all technical operations of the company. Was responsible for maintaining infrastructure and developing applications while leading a team of developers and other IT professionals working on internal company systems.
2. Built a custom, extensive VoIP/SIP platform based on FreeSwitch, used by nearly 100 active phone consultants.
3. Created advanced AdTech-related applications serving up to 50k dynamic RPS.
4. Led all IT operations and actively participated in most of the development as well as infrastructure tasks.
5. Created countless API integrations with external platforms: Voluum, Facebook, Google, Cloudflare, dozens of logistics companies, and other service providers.

ALX is a IT training company and consultancy shop for various technologies.

• Managed Linux-based infrastructure for clients;
• Developed a company internal CRM/CMS app based on Python/Django;
• Moved the app onto CI/CD pipeline and created an extensive test suite;
• Still conducts training sessions for ALX (e.g., Basic/Advanced Linux Administration, Programming in TCL/TK, PostgreSQL-based introductory SQL course, and various sessions related to Ruby on Rails).