From backend to wardrobe advice: an interview with Heiko Mettelsiefen, lead developer of dressbutler.com

When you think of fashion, you often have images of elegant catwalks, perfectly fitting outfits and sophisticated style advice in mind. When you think of software development, you tend to think of dark rooms, lines of code and hoodie-wearing developers. Heiko Mettelsiefen, lead developer at dressbutler.com, proves that these two worlds are a perfect match.

At 40, the computer scientist is already a veteran in the digitalisation industry and has previously worked for well-known companies such as jeweller Wempe, the Hamburg Medical Faculty and the Rheinische Post. As a family man, amateur chef and Asia lover, he brings not only technical expertise but also a good dose of humour to his job.in our exclusive interview, Heiko gives us a look behind the scenes at dressbutler.com, talks about his unintentional sideways entry into the fashion industry and reveals why even probably the worst-dressed developer in Hamburg suddenly has an opinion on suits.
Heiko Mettelsiefen, lead developer of dressbutler.com, photo: DressbutlerHeiko, you are a computer scientist and have worked for jewellers, newspapers and even a medical school. How did you end up at dressbutler.com?

Heiko: To be honest? It was probably a misunderstanding. I thought it was a platform for the efficient storage of clothes. I'm not sure if I really belong here, but now I can't go back.

Have you ever had an interest in fashion?

Heiko: I evolved once in terms of style: from ‘what's clean right now’ to ‘what's not totally crumpled’. But yes, now it's starting to fascinate me.

What does your typical work outfit look like?

Heiko: Dark jeans, hoodie and trainers. In other words, the standard outfit for developers. Dressbutler tried to change my style - but they quickly gave up.

What technical challenges did you face when developing dressbutler.com?

Heiko: Well, teaching artificial intelligence to teach a platform to have better taste than its users was not easy. Especially when I'm programming it.

What is the technical structure of dressbutler.com?

Heiko: The platform consists of several core components. The backend runs on a scalable cloud infrastructure that provides microservices for different functions. The AI-supported style advice is controlled by a combination of deep learning algorithms and rule-based decision models. Our API enables external partners to access our data. The actual web application is based on the so-called TALL stack, i.e. Tailwind, Alpine.js, Laravel and Livewire. We are currently using Laravel version 11. We use Python for some AI features, as it is particularly suitable for machine learning and data analysis. Our architecture includes various queues that process thousands of jobs every minute. We rely on a comprehensive monitoring system to ensure that everything runs smoothly. Another important component is open source software - we benefit greatly from the developer community and are very grateful to them.

What was the biggest technical challenge?

Heiko: One of the biggest challenges was integrating the AI style advice into an intuitive user experience. An AI can recognise patterns in data, but fashion is strongly influenced by subjective preferences. That's why we had to develop algorithms that incorporate both fashion trends and individual preferences. Scalability is also an issue - as the number of users grows, the system must be able to reliably generate personalised recommendations in real time.

How does dressbutler's AI style consulting work?

Heiko: Our AI is based on a mixture of neural networks and rule-based systems. First, it analyses the user's input - body measurements, favourite colours, preferred styles and previous purchase history. It then compares these with extensive fashion databases and current trends. Another important element is visual image recognition, which analyses items of clothing and suggests suitable combinations. The AI also learns from user feedback and continuously adapts its recommendations.

What data does dressbutler.com use for evaluation?

Heiko: We use a combination of anonymised user data, publicly available fashion trends and specially curated style profiles. Specifically, we collect information about preferred brands, colours, fits and previous purchasing decisions in order to make better recommendations. Of course, data protection and transparency are our top priorities - users can view and manage their data at any time.

Is there a feature that you are particularly proud of?

Heiko: Our algorithm recognises whether someone calls their jogging bottoms ‘casual chic’ or whether they are simply lazy.

What was your funniest moment at dressbutler?

Heiko: When I said ‘loafers’ in a meeting and everyone thought I meant shoes - but I meant a bug in the system.

Are there any fashion trends that you don't understand?

Heiko: Yes. All of them. But especially socks in sandals - unless they're developer socks.

How do your children react to the fact that you now work in the fashion industry?

Heiko: They think it's great. Since I've been here, I'm no longer allowed to comment on their outfits.

Im Interview: Lead-Entwickler Heiko Mettelsiefen, Bild: DressbutlerYou often travel to Asia. Have you found fashion inspiration there?

Heiko: Yes, actually! In Japan, there are vending machines that sell entire outfits. That would be something for me too - then I wouldn't have to decide for myself.

Would you describe yourself as a style icon?

Heiko: Only if ‘programmed chaos’ passes as a style.

What does your perfect working day look like?

Heiko: Coffee. Code. Not a single bug. More coffee.

What was the most bizarre feature ever proposed?

Heiko: A ‘Get dressed properly’ alarm. I personally would find that practical.

Have you already received styling tips from dressbutler yourself?

Heiko: Yes, but they were so revolutionary that I had to sleep on them first. For three months.

Where do you see dressbutler.com in five years' time?

Heiko: Hopefully still online. And maybe with an ‘emergency suit AI’ for forgetful developers.

Are there any items of clothing that you would never wear?

Heiko: Yes, anything that needs ironing.

How often do you get comments on your own style from colleagues?

Heiko: All the time. It's called ‘well-intentioned feedback’.

Have you improved your style by working here?

Heiko: I have at least learnt that socks with cartoon characters are not suitable for business meetings. But it took a long time.

What three things should everyone have in their wardrobe?

Heiko: 1. an emergency tie. 2. a jacket that doesn't date back to school. 3. something that your girlfriend/boyfriend has chosen - because then it's guaranteed to fit.

What is your most important lesson from the fashion world?

Heiko: ‘Black goes with everything’ is the holy grail of the lazy.

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Heiko Mettelsiefen impressively proves that fashion and IT can be an unbeatable combination - even if he doesn't quite feel he has arrived in this world yet. With a mixture of humour, technical talent and a pinch of chaos, he ensures that dressbutler.com is not only stylish, but also intelligent. And who knows? Maybe one day we'll see him in a perfectly fitting suit after all - albeit reluctantly.