Open to opportunities

Grzegorz Milanowski

@grzegorzmilanowski

Message

Senior full-stack developer modernising Ruby on Rails systems.

Poland

Message

What I'm looking for

I’m looking for a senior full-stack role where I can modernize Ruby on Rails systems, reduce technical debt, and improve security and performance—collaborating with international teams on meaningful product work.

I’m a Senior full-stack developer specializing in Ruby and Ruby on Rails, with a supplementary skillset in JavaScript and React. I enjoy taking complex, legacy codebases and turning them into maintainable systems that perform reliably at scale.

At Ciklum, I modernised application architecture by decoupling and removing dependencies on legacy middleware and obsolete code. I optimized server resources by safely decommissioning unused tenants, resolved long-standing security vulnerabilities and code quality issues reported by Checkmarx, and restored Sidekiq background processing hygiene.

Previously at Zen Educate, I revamped critical views to improve usability and performance, and supported search capabilities using Elasticsearch. I also helped transition an early prototype into a mature product through extensive refactoring across legacy Ruby on Rails and React codebases.

Earlier roles included leading performance improvements (cutting a complex edit view load time from ~3 seconds to ~0.6 seconds), refactoring legacy payment functionality, and restructuring an API toward a GraphQL architecture. I’ve also contributed to React/Redux frontends, maintained Rails/AngularJS monoliths, explored microservices with RabbitMQ, and supported teams through cross-functional collaboration.

Experience

Work history, roles, and key accomplishments

Current

Senior Full-Stack Developer

Current

Ciklum

Jun 2024 - Present (2 years 1 month)

Modernised a legacy multi-tenant loyalty platform by decoupling and removing dependencies on obsolete middleware and dead code. Improved security by resolving multi-year Checkmarx-reported vulnerabilities and restored background job health by clearing a long-unmaintained Sidekiq dead jobs queue.

Ruby Ruby on Rails MySQL Sidekiq Terraform Checkmarx AWS Docker

Senior Full-Stack Developer

Zen Educate

Nov 2022 - Jun 2024 (1 year 7 months)

Revamped views to improve usability and performance while supporting and expanding application search capabilities with Elasticsearch. Refactored and transitioned a Ruby on Rails + React codebase from early prototype to a mature product and helped bootstrap a new product.

Ruby Ruby on Rails JavaScript Redux React Hooks PostgreSQL Elasticsearch RSpec React

Consultant

Test Driven Solutions Ltd.

Jun 2021 - Nov 2022 (1 year 5 months)

Led performance improvements to a frequently used edit view, reducing load times from ~3 seconds to 0.6 seconds by refactoring Ruby Enumerable logic into an ActiveRecord-only approach. Managed a large employee administration application and supported ongoing maintenance and development for client solutions.

React Ruby Ruby on Rails JavaScript Flux MySQL AWS Docker jQuery

Full-Stack Developer

Nokia

Sep 2017 - Dec 2019 (2 years 3 months)

Led development of an API-only application and migrated a legacy Rails app to use a new Enterprise Jira API-based integration. Built a React/Redux frontend, maintained a Rails/AngularJS monolith, and explored microservices using RabbitMQ while supporting Python automation scripts.

React Ruby Ruby on Rails JavaScript Redux AngularJS Python RabbitMQ PostgreSQL Cypress

Education

Degrees, certifications, and relevant coursework

Self-taught

Independent study, Computer Science

2015 -

Activities and societies: The Odin Project (https://github.com/ToTenMilan/the_odin_project#readme); books and courses (https://github.com/ToTenMilan/books-courses#readme).

Pursued computer science through self-directed learning using books and online courses.