Application Architect & Consultant

I help companies transform large, messy Rails apps into fast, maintainable systems.

Services

Over the last 10 years working with Ruby and Rails, I figured out what are the areas in which I can add the most value.

Ruby on Rails Codebase Refactoring

I specialize in refactoring large, legacy Rails applications to make them faster, easier to work with, and less bug-prone. Using proven object-oriented principles, I untangle business logic, reduce technical debt, and improve long-term maintainability — without breaking production.

Object-Oriented Design & Architecture Consulting

I help teams improve the internal design of their Ruby applications through better encapsulation, modularization, and domain modeling. Whether you’re moving toward service objects, DDD, or just cleaner POROs, I’ll guide you in designing code that’s easier to test, extend, and reason about.

Test Suite Improvement & Architecture

A healthy test suite is the foundation of sustainable development. I help teams improve or restructure their RSpec or Minitest test suites — making tests faster, more reliable, and easier to maintain, while introducing practices like test layering and dependency injection.

Codebase & Architecture Audits

I offer short-term audits of Rails codebases to identify design flaws, performance bottlenecks, and maintainability risks. Deliverables include a written report, annotated examples, and a practical, phased roadmap for improvement.

Performance Optimization in Rails

I diagnose and fix Rails performance issues at all levels — from slow SQL queries and inefficient ActiveRecord usage to bloated request cycles and background job bottlenecks — with a focus on measurable wins and long-term stability.

Developer Mentoring & Pair Programming

I provide hands-on mentorship to Ruby developers, helping them grow in areas like OOP principles, Rails idioms, and clean code practices. I also pair with teams to solve thorny architectural issues and model complex domains clearly and simply.

Matej joined Primehammer as a junior developer, and from the very beginning, he stood out for his professionalism, work ethic, and eagerness to learn. He quickly became someone we could rely on to deliver solid, well-tested code and to take ownership of features from start to finish.

David Hrachový

CEO, Primehammer Ltd.

Matej played a foundational role in shaping Zeilenwerk’s engineering culture and technical direction. He established solid development processes, introduced best practices, and brought structure to our workflows. His leadership, calm presence, and ability to mentor others helped us grow into a strong, effective development team. Matej was someone I could always rely on to deliver, think strategically, and raise the bar for quality across the board.ever thought possible.

Raphael Reber

CEO, Zeilenwerk GmbH

Matej brought incredible value to Createview from day one. He took full ownership of our Rails backend — designing, building, and optimizing complex features with minimal guidance. His ability to turn vague ideas into production-quality software was impressive, and he consistently delivered clean, thoughtful solutions. On top of that, he mentored junior developers with patience and clarity, raising the overall quality and confidence of the team.

Alastair Brunton

CTO, Createview AS