Portfolio

Hi there, I'm Marc 👋

I'm a generalist senior software engineer. On this page I want to show you

• what I'm good at
• the kind of projects I've worked on in the past
• how I work

...and blatantly convince you to work with me 🌱🤗

What I'm Good At

Throughout the past decade, I've worked on all parts of the stack (frontend/backend/db/infra/etc). I love learning new technologies by building projects to scratch my own itch, and writing about what I learn to spread my knowledge.

Frontend Engineering and UX

I'm extremely good at making products feel high quality by creating delightful user experiences through exceptional frontend engineering.

Over the years, I've gained deep expertise in everything frontend. Be it frameworks, accessibility, SEO, state management and architecture, UI/UX design, integration testing, design systems, headless CMS, A/B testing, animations...

...or obscure things like knowing the most semantically correct way to specify subheadings in HTML (tl;dr: people disagree a lot, see e.g. here or here).

I've designed and built frontends for companies like flowkey, EigenDA, ReviewLayer, ephema, and ZuBerlin/ZuGarden.

Thinking like a business

I don’t just build products. I figure out what’s worth building.

It's about knowing what to build by identifying the bottlenecks and small steps that will have the biggest impact.

Most engineers don't think that way. Instead, they think in terms of architecture or performance, and ultimately just code. While important, constantly asking why is missing.

I've founded and worked on several businesses – a bootstrapped SaaS, a paid newsletter, a web3 research company, an event business, and an independent consulting business.

Going from 0 to 1

Once I know what to build, I can make almost anything a reality. From useful tools, to little games, art projects, integrations, websites, and fullstack real-time applications: I love taking care of design, copy, and code.

Selected Projects

Improving Ethereum's scalability by developing a blob sharing solution

Ethereum launched blobs in 2024, a very much needed but inefficient way to store data onchain. But there's a problem: You overpay in most cases because you can only post full blobs.

For the web3 research org ephema, I designed and built a working blob sharing solution from start to finish. It worked so well that we won the ETHGlobal Scaling Ethereum hackathon and landed a six-figure grant from the Uniswap Foundation and Arbitrum DAO.

Read the full story if you're curious about the economical and technical details of making Ethereum more efficient and cheaper using blob sharing.

The project was built with Node.js/Express/Typescript, Postgres with Prisma, Solidity, Next.js/React, Tailwind with shadcn/ui, wagmi/viem, and react-query.

Increasing team efficiency by building internal tools and refactoring legacy APIs

flowkey’s webapp was built on Meteor, a great framework until you need to build apps for other platforms and scale. Over the years, tech debt piled up, and the dev team was struggling to ship new features.

To fix this, we did a full backend migration from Meteor to a modern GraphQL API. I took care of refactoring the payment infrastructure, webhooks, and authentication system. On the frontend, I transitioned the codebase to React.

The result was a faster, testable and scalable backend, which allowed the team to ship faster and with more confidence.

The project was built with Node.js/Express/Typescript/GraphQL/MongoDB and Next.js/React, Apollo GraphQL, and Emotion CSS.

Building fast, beautiful and effective landing pages

Every great project needs a website.

I’ve designed, built, and optimized landing pages for startups, SaaS products, and research organizations—helping them convert visitors into customers. At flowkey, I led the website team, focusing on performance, SEO, and UI/UX.

Some of the sites I’ve built:

• ZuBerlin & ZuGarden – Researched-focused web3 popup village
• ephema – web3 research org
• Mental Garden – Personal reflection newsletter
• EigenDA Docs – Developer-friendly documentation

The projects were built with technologies such as Typescript, Next.js/React, Tailwind, and Payload CMS with MongoDB.

Enabling audience participation by building a real-time app for Germany's biggest nonprofit live game show

Live events are great. But usually, the audience just sits there, watching. What if they could participate in real time?

For Wer besiegt Paul, Germany’s biggest nonprofit live game show, I built a real-time web app that let 800+ audience members vote, track scores, and even compete. All while maintaining high performance and responsiveness despite extreme traffic spikes.

I took the project from idea to deployment, including UX, frontend, product design, backend/DB architecture, and real-time interactions.

The project was built with JavaScript, Meteor, React, and Material UI.

My Guiding Principles

1. Balance Speed & Quality – I know when to move fast and when to invest in maintainability
2. Think Like a Founder – I don’t just write code. I find the highest-leverage work to push a project forward
3. Collaboration & Mentorship – I believe in over-communication, thorough code reviews, and growing as a team
4. I Ship – No endless tinkering. I make sure things get delivered and make an impact
5. Craftsmanship – I do high quality work.

Contact Me

I am currently available on a consulting basis for new projects.

If you need:

• A senior engineer who can own a project from idea to production
• A technical consultant to improve your product’s frontend, backend, or architecture
• A problem-solver who thinks beyond just code

Then drop me a line at [email protected]. I'll get back to you fast.

Oh, and if you're ever in Berlin, let's meet for coffee!