My name is Cezary. I'm an experienced full-stack Ruby on Rails developer at Visuality, a Ruby on Rails software house from Warsaw, Poland. I specialize in Rails and DevOps, with a growing focus on AI/LLM integrations in web applications. Before software I designed power distribution grids and ran IT infrastructure.

#what-i-work-on

Most of my work is client projects, so a lot of it lives behind the scenes. The kind of problems I spend my time on:

• Building and scaling Rails applications for real businesses — features, integrations, and the operational side of keeping them healthy.
• Designing APIs and webhooks that external partners build on, and ingesting third-party APIs.
• Bringing LLMs into production Rails apps in a way that's actually useful to end users.
• Deployment and infrastructure — cutting cost and complexity without downtime.

The clearest public example is Viewcy — an event-promotion and ticketing platform for musicians and creative-arts professionals (Rails on Heroku, Next.js on Vercel). Working directly with the US-based owner, I build features, develop and integrate partner APIs and webhooks, ship an LLM-powered AI agent for end users, migrate Rails views to a separate Next.js frontend, and keep an eye on performance and security.

#what-i-focus-on

• DevOps & deployment — Kamal, Docker, AWS / Hetzner / DigitalOcean, CI/CD with GitHub Actions. I once migrated a trading platform to AWS with Kamal and cut annual hosting costs by ~$40k.
• Rails at scale — service objects, REST and GraphQL APIs, performance optimization, PostgreSQL and Redis.
• AI / LLM in Rails — building AI agents and workflows, and integrating the Model Context Protocol (MCP) with existing Rails applications.

#i-speak--run-workshops

• Ruby Community Conference — workshop: using Kamal with Ruby on Rails
• Warsaw Ruby Meetup (PLRUG) — talk: MCP integration with legacy Rails applications

#i-write

• Kamal Hooks — How to Track Deployments on GitHub
• Optimizing Cloud Infrastructure by $40,000 Annually
• GraphQL in Ruby on Rails: How to Extend Connections

#open-source

Occasional contributions to the tools and gems I rely on:

• crmne/ruby_llm
• exoego/rspec-openapi
• shakacode/react_on_rails

#toolbox

Ruby · Rails · JavaScript · Turbo / Stimulus · Next.js · React · PostgreSQL · Redis · Sidekiq · RSpec · GraphQL · Kamal · Docker · AWS · Heroku · Vercel · GitHub Actions

#connect-with-me

• Visuality org: @visualitypl
• LinkedIn: in/cezary-kłos-software
• Twitter / X: cezaryklos
• Email: cezary.klos@gmail.com