MM

Selected work

Things I’ve built and run

Four projects from work, my home village and my spare time — what each was, what I did and what I learned.

Process & systems

Bringing five sites onto one project portfolio system

2023–present · Business-side system owner

Helping a global biologics manufacturer run all of its projects on one shared platform — site by site.

What it was

A multi-year rollout of a project portfolio management system built on Microsoft Power Platform. It replaced fragmented, site-specific tracking with one shared way of running projects. Five sites across Europe, the US and Japan are live, with one more in preparation — around 50 users managing roughly 150 projects.

What I did

  • Acted as the bridge between project managers, finance and the implementation team — turning business needs into system requirements, and system changes into ways of working.
  • Ran fit-gap analyses and redesigned core processes, captured in SOPs adopted across sites.
  • Prepared and led on-site training and go-lives, and built a network of super users at each site.
  • Designed 15 Power BI reports that cut KPI reporting from about an hour to minutes.

What I learned

  • The hard part of a rollout isn’t the configuration — it’s getting sites with different working cultures to agree on one way of doing things.
  • A standard only sticks if it makes someone’s job easier on day one, not “eventually.”
  • Every question a user has to ask twice is a documentation gap, not a training gap.
  • Power Apps
  • Power BI
  • Process design
  • Change management
  • Training

Community events

Village festivals for around 1,000 guests

2017–2019 · 2023–2025 · Organizing team — finance, funding & volunteers

Two festival series in my home village of Bordenau, run by volunteers for around 1,000 guests.

What it was

First came “Color My Life” (2017–2019), a Holi-style color festival where guests throw colored powder. After a COVID break we started “Hajo dreht auf” (2023–2025) — roughly “Hajo turns it up,” named after a local man. It’s more themed and decorated: a cozy atmosphere rather than a party out of the box. Alongside the festivals, I’m an elected member of Bordenau’s local council.

What I did

  • Owned finance and funding — budgeting and fundraising, with plenty of work long before and after each festival.
  • Organized all volunteers for the festival day and the week of preparation before it.

What I learned

  • Everyone has a day job, nobody reports to you, and the date doesn’t move — the best stakeholder-management training I’ve had.
  • Contingency planning matters more than the plan itself — the value is in having already thought through what happens when something goes wrong.
  • Community projects succeed when people feel ownership, not when the plan looks good on paper.
  • Event management
  • Budgeting & fundraising
  • Volunteer coordination

Side project

Citchen — my personal cookbook app

May 2026–present · Solo project, built with Claude Code

An installable, offline-first cookbook app I designed and built with AI — try it yourself.

What it was

It started with wanting to cook better. Citchen (spelled that way on purpose) is an installable, offline-first web app with around 105 recipes, a shopping list grouped by supermarket aisle, meal planning, pantry stock and a step-by-step cooking mode. Recipes sync through your own Google Drive, the interface switches between German, English, Spanish and Danish, and optional AI features run on your own API key — no server involved.

What I did

  • Defined the scope and made the architecture decisions — offline-first, no backend, and bring-your-own-key for the AI features.
  • Built it almost entirely through AI-assisted development with Claude Code, working in phases with clear checkpoints.
  • Rebuilt it from the ground up as a second version, keeping every feature from the first.

What I learned

  • With AI writing the code, the skill that matters is knowing what to ask for — and spotting when the answer is wrong.
  • Early architecture choices — no server, data in your own Drive — kept the app simple to run and free to share.
  • Building something end to end surfaces a hundred small decisions you never see when you only review someone else’s spec.
  • Progressive web app
  • AI-assisted development
  • Claude Code
  • Offline-first
Try the app(opens in a new tab)

Entrepreneurship

henmarsell — an online shop for pond fish towers

2021–2025 · Co-founder, with my brother Henrik

A small online business I co-founded with my brother Henrik — and later sold to our manufacturer.

What it was

We sold pond “fish towers”: a plexiglass column held under negative pressure, so the water stays inside it above the pond surface. Goldfish and other pond fish swim up into it, where you can see them from further away — and they look larger. The towers were made by a German manufacturer; we sold them through our own web shop and on Amazon.

What I did

  • Owned sourcing, pricing, marketing and fulfillment.
  • Set up and ran both sales channels — our own web shop and Amazon.
  • Sold the business to the manufacturer for €15,000, after it had generated around €50,000 of value.

What I learned

  • Small businesses run on logistics and iteration, not big strategic moves — small, consistent decisions on listings, pricing and shipping compound.
  • Running something end to end, with your own money and time on the line, builds a different kind of confidence than working inside someone else’s system.
  • E-commerce
  • Amazon
  • Pricing & marketing