Web applications · backend

I build web applications your users can rely on.

Custom software from MVP to production. Hands-on development and architecture—or fractional CTO support when your team needs a senior lead.

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mateusz@rubycon: zsh

About

Developer with a CTO background

I build and run web applications, from backend code to technology decisions.

Web developer with experience leading engineering teams as a CTO. I write code and I make technology choices that fit the business.

I work with startups and established companies that need senior help without a full-time hire: shipping features, reviewing architecture, or getting through a tough migration.

Mateusz Górniak

Services

How I can help

Web application development and ongoing product work—for teams that need a senior developer without a full-time hire.

Web application development

Design and build custom web apps—from first release to long-term product work.

  • MVPs and new product builds
  • Feature delivery on existing apps
  • SaaS and internal tools
  • Integrations with third-party services

Fractional Developer

Senior hands-on work when you need extra capacity.

  • Backend development and API design
  • Code review and quality improvements
  • Mentoring your team
  • Production debugging

Fractional CTO

Technology leadership without a full-time role.

  • Roadmap and architecture
  • Team structure and hiring
  • Legacy system assessment
  • Build vs. buy decisions

Stack

Technologies I work with

Ruby is where I'm most at home. I choose tools that fit the problem, not the other way around.

Main stack

Fast to build and easy to change. A strong fit for MVPs and products that need to evolve quickly.Ships features with less glue code. Lower maintenance cost and a large pool of developers.Reliable data storage that scales with the business. No need to swap databases early.Keeps the app fast under load. Handles caching and short-lived data without slowing users down.Background jobs for emails, reports, and imports. The app stays responsive while work runs async.

Also worked with

Catches bugs before release. Safer refactors as the codebase and team grow.Good for APIs and tooling when the team already works in JavaScript.Useful for integrations, data tasks, and connecting to AI or ML services.Same setup in dev and production. Fewer surprises when you deploy.Hosting that grows with the product. Turn services on when you need them, not before.

Happy to join your existing stack or help pick the right one for a new project.

Expertise

Where I focus

From overall system design down to specific problems. Hover a tag to see what I actually do in each area.

I design systems from scratch or steer existing ones so you can add features without rewriting, server costs stay reasonable, and scaling is straightforward when traffic grows.I help shape the team, agree on how you write and review code, and mentor people so shipping does not hinge on one developer.I write the core application code: business logic, databases, background jobs. The layer that has to work reliably every day.I design APIs your frontend and partners can build against without surprises as the product grows.I set up monitoring so we are not guessing what happens in production. Bugs surface fast, trends show up in the data, and we track SLOs and spot bottlenecks before users feel them.I move old codebases forward step by step. The business keeps running, risk goes down, no big-bang rewrite.I use AI where it saves me real time, and I review what goes to production so quality does not slip.

Process

How I work

Business goals first, then the technical plan.

1

Assess

Look at the codebase, the team, the constraints, and what success means for the business.

2

Plan

Agree on a technical approach with realistic milestones. No unnecessary complexity.

3

Deliver

Regular updates, working software, and knowledge passed on to your team.

Contact

Let's talk

Working on something or want to see if we fit? Send a message.

Or reach out directly