Hi, I'm
Krzysztof Słomka
Senior Backend Engineer & Software Architect | PHP, TypeScript, Java & Go | Distributed Systems, AWS, Fintech
Kraków, Poland
$
about
I build backend systems that have to keep working. Fintech platforms, payment APIs, SaaS products, high-traffic web apps. Fifteen years of it, mostly in payments, factoring, and lead generation. My focus is backend architecture, distributed systems, event-driven design, and the platform engineering around them: cloud-native services on AWS and GCP, API design, observability, analytics pipelines. Also the unglamorous job of modernizing backends nobody wants to touch. I'm backend-first, but I ship whole products when the job needs it, with React, Next.js, Svelte, or Electron on the other side.
AI changed how I work more than any tool I picked up in the last decade. I wrote down how I use it, and where I still don't trust it, in my AI manifesto →
I also write about fintech, distributed systems, and DDD on the blog, most recently Ruflo: What a Swarm Orchestration Layer Actually Adds to Claude Code →
15+ years in the industry
skills
AI Engineering
Languages
Frontend
Data & Messaging
Architecture
Frameworks
Cloud & DevOps
Platform Engineering
experience
Irbis Software
Business Owner
Kraków, Poland · Nov 2013 — present
- Independent B2B consulting and software development projects focused on backend systems, automation, and custom business platforms.
- Architecture advisory, backend engineering, and DevOps setup for small and mid-size teams, run alongside contract engagements.
- AI-assisted engineering workflows and LLM integrations: agent tooling, MCP-based automation, and internal knowledge systems layered on existing codebases.
Excel Impact
Senior Software Engineer
Miami, FL, USA (Remote) · Apr 2023 — May 2026
- Led migration of legacy backend services from PHP to NestJS and TypeScript, improving scalability, maintainability, and operational visibility.
- Designed distributed backend services and APIs for high-scale lead-generation and fintech-related platforms.
- Designed platform architecture, observability tooling, event tracking systems, and BigQuery-driven analytics pipelines.
- Built backend debugging workflows using OpenSearch, structured logging, and operational monitoring.
- Improved engineering standards across services: project structure, documentation, logging strategies, best practices.
- Conducted backend performance audits and optimization initiatives, improving reliability and developer experience.
Volt.io
Senior Software Engineer
Cracow, Poland (Remote) · Feb 2024 — Nov 2024
- Designed secure backend services and payment-related APIs for fintech and open banking solutions.
- Contributed to a global payment API gateway supporting payment initiation and processing across regions and banking providers.
- Improved distributed payment systems for scalability, low latency, reliability, and fault tolerance.
- Applied CQRS, DDD, and distributed-systems principles in production fintech environments on AWS.
Ibexa
Senior Software Engineer
Kraków, Poland (Remote) · Dec 2022 — Apr 2023
- R&D for Ibexa DXP; built REST APIs and backend services for third-party integrations and enterprise extensibility.
- Ran architectural evaluations jointly with product and engineering teams on modernization opportunities.
PragmaGO.tech
Software Architect
Kraków, Poland · Jun 2018 — Dec 2022
- Designed distributed architecture for fintech platforms and backend services focused on scalability and high availability.
- Designed microservice-based systems, integration layers, communication contracts, and event-driven solutions.
- Led architectural initiatives across teams: engineering standards, code quality, mentoring, technical documentation.
- Designed and optimized CI/CD pipelines and containerized environments (Jenkins, GitHub Actions, Docker, Kubernetes).
PragmaGO.techSenior Software EngineerDec 2015 — Jun 2018
- Built backend services and financial modules for fintech/factoring: settlement, reconciliation, reporting, integrations.
- Designed backend architecture, APIs, async workflows, and integration layers using PHP and Node.js.
PHP, Symfony, API Platform, Node.js, TypeScript, PostgreSQL, RabbitMQ, ElasticSearch, Jenkins
TVNSoftware EngineerJul 2014 — Dec 2015
- Built high-traffic backend for TVN24biz, a large-scale CMS handling millions of articles and media assets.
- Contributed to an internal CMS built with Symfony, improving editorial workflows and search capabilities.
PHP, Symfony, MySQL, JavaScript, Jenkins
AKRA PolskaPHP Backend EngineerOct 2013 — Jul 2014
- Built backend applications and custom web platforms for e-commerce and business-oriented solutions (key2print.pl, wszycyklikamy.pl).
PHP, Symfony, Laravel, Zend Framework, Sylius, MySQL
Ezotic.plTeam LeaderMay 2013 — Oct 2013
- Led a small development team for backend and billing systems for enterprise clients.
- Designed and implemented a billing and integration system for Energa S.A.
PHP, CakePHP, MySQL, JavaScript, UML
Rise AgencyWeb DeveloperMar 2012 — May 2013
- Developed custom web platforms and CMS-based solutions for clients including Royal Canin and Fenix Group.
- Built couponing systems and product-finder applications tailored to client requirements.
PHP, Symfony, MySQL, JavaScript, jQuery
FreelanceFreelance Web Developer2008 — 2012
- Delivered custom websites and web applications for small businesses and individual clients.
- Managed Linux-based hosting environments and production deployments.
PHP, MySQL, Linux, JavaScript
