/* global React */ const { useState, useEffect } = React; /* ============================================================ TIMELINE / EXPERIENCE Companies are top-level; phases (e.g. multiple roles at one company) nest as sub-rows inside the expanded view. ============================================================ */ const EXPERIENCE = [ { id: "metso", period: "06.2024 — Now", co: "Metso", loc: "Krakow, Poland", role: "Senior Software Engineer & Product Owner", detailMeta: "Industrial Digital Twin · 3 phases", summary:
Joined as a Full-stack Developer on a digital-twin platform for the minerals processing industry; promoted into Feature Owner and now a dual Senior Software Engineer + Product Owner role. Three roles, one mission.
, tags: [".NET 9", "C# 13", "React 18", "Microsoft Orleans", "Azure", "Terraform", "DataDog", "Digital Twin", "AI-native"], now: true, phases: [ { period: "Feb 2026 — Now", duration: "4 mos", role: "Senior Software Engineer & Product Owner", meta: "Dual role · NOW", now: true, body: <>Acting in a dual role as Product Owner while remaining hands-on as a Senior Software Engineer. Leading end-to-end development and delivery of the digital-twin solution with .NET, React, and Microsoft Azure.
Driving an AI-native development approach — embedding intelligent capabilities for advanced analytics, automation, and data-driven decision-making. Defining high-level architecture, shaping technical direction, and bridging engineering with product through roadmap planning, requirements, and stakeholder collaboration.
> }, { period: "Dec 2025 — Now", duration: "6 mos", role: "Feature Owner", meta: "Concurrent", body: <>Feature Owner of the Digital Twin product. Managing a development team, communicating with business and stakeholders, and creating development plans and feature roadmaps aligned to quarterly objectives.
Backlog ownership, scope definition, requirements clarification. Coordinating delivery, presenting Digital Twin demonstrations, and ensuring alignment with Metso's product strategy and digitalization goals.
> }, { period: "06.2024 — 12.2025", duration: "1.5 yrs", role: "Full-stack Software Developer", meta: "IC track", body: <>Building distributed services in C# 13 / .NET 9 with Microsoft Orleans, shaping the React 18 UI on top, and migrating legacy VM workloads to Azure with Terraform-managed infrastructure.
Stood up service & infra observability with DataDog, set up CI/CD on GitHub Actions, and contributed to architectural decisions across the squad.
> }] }, { id: "siemens", period: "06.2022 — 05.2024", co: "Siemens DISW", loc: "Katowice, Poland", role: ".NET Developer", detailMeta: "Enterprise software · AWS", body: <>Built back-end APIs in C# / .NET for industry-leading EDA tooling. Applied functional C# for scalable solutions and integrated multiple third-party services.
Owned GitLab CI/CD pipelines and managed cloud infrastructure on AWS with IaC. Drove security & compliance, set up service observability, and participated in the full lifecycle of product development.
>, tags: [".NET", "C# Functional", "GitLab CI/CD", "AWS", "IaC", "Observability", "Security & compliance"] }, { id: "autocab", period: "04.2020 — 05.2022", co: "Autocab Ltd (an Uber company)", loc: "Stockport, England", role: "Software Developer", detailMeta: "Mobility platform · .NET + Angular", body: <>Developed REST APIs in ASP.NET / ASP.NET Core and integrated them into Angular UIs. Designed and managed MS SQL and MongoDB databases, maintaining a long tail of legacy ASP.NET projects alongside greenfield work.
Built server logic for a new food-delivery product for taxi companies, owned production deployments, and authored technical documentation for the platform's APIs.
>, tags: ["ASP.NET Core", "Angular", "MS SQL", "MongoDB", "Legacy modernisation", "Production deploys"] }, { id: "csi", period: "09.2019 — 04.2020", co: "CSI Media", loc: "Crewe, England", role: "Junior Web Developer", detailMeta: "Agency · Microservices", body: <>Built web applications in ASP.NET / ASP.NET Core, maintained and extended microservices, and worked across MVC and MVVM architectural patterns with several ORM frameworks.
>, tags: ["ASP.NET", "Microservices", "MVC", "MVVM", "ORMs"] }, { id: "tribal", period: "02.2019 — 07.2019", co: "Tribal Group", loc: "Swansea, Wales", role: "Support Consultant", detailMeta: "Dynamics 365 · First role", body: <>Provided support to Dynamics 365 customers and deployed software to customer sites — first taste of professional software delivery alongside finishing my BSc.
>, tags: ["Dynamics 365", "Customer support", "Deployments"] }]; function PhaseRow({ phase, idx, total, isOpen, onToggle }) { return (Click any row to expand. Companies with multiple roles unfold as a sub-timeline.
Five years on UK campuses — first in Wales, then a Russell-Group MSc with Distinction in Manchester. British academic rigour underwrites every line of code I ship.
I'm Marcin Kolber — a .NET & React engineer who builds the thing and owns the why. British-universities graduate (MSc Distinction, Manchester) now shipping distributed systems out of Kraków.
I split my week between writing .NET and React and being the Product Owner who decides what gets written. Same person on both sides of the refinement table — fewer translation losses, sharper backlog.
I'm at my best on small, senior teams shipping into a real domain — industrial IoT, mobility, EDA, anything where correctness matters and stakeholders are demanding. I prefer written-first comms, short feedback loops, and roadmaps that survive contact with reality.
Updated May 2026
{it.body}