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Ella Cope, Founder and CEO of Della Yellow, sat down with Onyx for a feature-length interview.
Could you start by introducing yourself and explaining how you ended up at Della Yellow?
I entered sustainable fashion in an unusual way. I have an engineering background but have always been drawn to creative things. After university, I wasn’t exactly sure what I wanted to do—except that sustainability was key for me. It may seem risky to start a business at that stage, but for me, it was the perfect time. I wasn’t walking away from anything else, and that little bit of naivety can be a strength. So I built Della Yellow about two and a half years ago. We created an app—kind of like Duolingo, but for sewing—designed to teach people how to repair and upcycle clothing through clear, expert-led tutorials.
So the idea is to extend the life of garments, letting people customize and personalize their clothes—a kind of revival of a dying art?
Exactly. My Dutch grandma, my Oma, taught me how to sew when I was young. Nowadays, most people our age have never learned because it’s no longer part of the school curriculum. And in an era saturated with digital content, there’s a real desire to get back to hands-on, physical craft. We’re tapping into that movement and addressing it in a scalable way.
You mentioned your educational journey earlier—you did a foundation year in Art at Oxford Brooks, then Design Engineering at Imperial, right?
Yes. I did a lot of art and maths in school, and the typical advice was to go into architecture. I initially set my sights on an art degree after a foundation year. But I missed the structure and problem-solving we’d done in school, so I discovered design engineering at Imperial. It was a unique mix—combining traditional engineering skills, product design, enterprise, and entrepreneurship. I met lots of cool and creative people there, and that’s when I shifted my focus toward sustainability.
I always felt that Imperial lost a lot by lacking humanities based subjects—did you feel that absence?
I’d agree. Humanities weren’t a major part of the conversation, and most of our cohort came from similar, highly technical backgrounds. However, design engineering sat slightly outside that narrow focus. The 50/50 gender split—which was unusual at Imperial—helped create a more balanced and well-rounded environment. It attracted individuals with a strong creative mindset, showing that even within an engineering context, there was space for diverse approaches to problem-solving.
Did your foundation year give you an edge over others who hadn’t had that experience?
Absolutely. Living away from home for a year taught me a lot about independence and life beyond academics. I went into university feeling more confident—not just academically, but in a well-rounded, personal sense. That break from being overly goal-oriented was healthy and really set the tone for everything that followed.
Let’s talk more about Della Yellow. You’ve described it as the Duolingo for sewing. What exactly do you offer?
We started with in-person workshops in London, teaching hundreds of people how to sew. Our goal was to learn how people pick up new skills—what they found hard, what was intuitive—especially since many had tried to learn from online tutorials on YouTube only to get stuck when their own projects didn’t match the examples. There’s no one there to help you in real time, so we wanted to create an interactive, community-based approach.
After the workshops, we set up a sewing school WhatsApp group. With about a hundred members, that group was invaluable for understanding what our learners really wanted. People weren’t just talking to us; they were exchanging photos of their projects and helping each other out. That community aspect was a pleasant surprise and ended up shaping much of the app’s design.
We still host some in-person events, but the scalable part of our business is definitely digital. The in-person workshops serve as a supplement to the core app experience.
So the app now incorporates that community feel, along with some gamification, even if it’s still at an MVP stage?
Exactly. We built the app for iOS and Android and continue to develop it based on real user feedback. Every startup goes through that iterative process—get something out there, learn from it, and then add or tweak features.
The sustainable and secondhand market is huge, but how did you initially build a community of people interested in repair and upcycling?
We grew our following organically on Instagram and TikTok. We’re also based at Somerset House, which is a hub for creative groups. We reached out to these young, creative people—essentially Gen Z and young millennials—who are naturally drawn to sustainability and hands-on creativity.
I remember that early on, you even offered a service where people could send in their clothes for repair or customization?
That was our first iteration. However, we found it challenging to balance sustainability with one-off repair projects—the service model wasn’t scalable or becoming profitable. So we shifted our focus to education. Our vision now is to become a B2B business by licensing the app to clothing brands. The idea is that brands offer the app to their shoppers as a cost-effective alternative to traditional repair services. The shopper gets the app for free and earns rewards with the brand when they complete projects, making it a win-win scenario.
So you’re not physically repairing items; you’re empowering people to repair their own clothes through education?
Exactly. It’s a white-label solution tailored to each brand, with tutorial videos featuring products from that brand. It offers a more affordable repair service—especially for lower-cost items where the unit economics of spending extra on repair wouldn’t make sense.
For most consumers, the big question is: “How hard is this going to be? Am I likely to mess up?” What’s the most common repair you teach, and how challenging is it?
The most common repair is fixing a button. It’s our staple lesson. Many people claim they can sew on a button, but when it comes down to it, they have no real experience. We approach it with the mindset that everyone is a beginner. Sewing a button is low stakes—if it doesn’t work out, you can simply try again. It’s not like you’re cutting into your favorite fabric or something irreplaceable.
And what about more complicated repairs?
Once someone is comfortable with the basics, we move into more complex projects—like transforming one garment into something entirely new, for example turning jeans into a pleated skirt . It’s like learning a language: you never truly finish because there’s always something new to master, but you have to start somewhere.
Zooming out a bit—how big do you see sustainable fashion as an industry, and how important is your idea in that context?
There’s a major cultural shift underway. I’d compare it to yoga 20 years ago—it was once niche, reserved for a few alternative types, and now it’s mainstream, with billion-dollar brands like Lululemon emerging from that space. Similarly, sustainable fashion is gaining traction. Consumer choices are driving the market now, and younger generations are actively choosing more sustainable options. It’s a powerful shift.
There’s also a legal shift in the UK. There’s incoming legislation called Extended Producer Responsibility, or EPR. Right now, when a brand sells clothing, they essentially wash their hands of it once it leaves the store. Under EPR, however, brands will have to pay a tax on each garment sold—a tax that goes toward recycling, sorting fabrics, and overall end-of-life management. Brands have the opportunity to reduce this tax if their garments are designed for repairability and easy recycling. In short, if a garment is more “circular” by design, it’s less costly for the brand.
Why do you think consumers are shifting their choices so dramatically?
There are several factors. The environmental impact of fast fashion is obvious, but it’s also about aspiration. In the past, wearing a hand-me-down or something from a charity shop was something you’d hide. Now, vintage pieces are a point of pride—people love to say, “I have this vintage jumper that no one else does.” It reflects a broader cultural change where being unique and sustainable is seen as aspirational.
I recall that even back in school, thrift and charity shop culture was already emerging. Do you ever worry there might be a shortage of vintage clothing?
Not really! There’s enough clothing on the planet right now to clothe the next six generations, even if there’s a saturation of low-quality, fast fashion items. In essence, there’s more than enough for everyone.
When we talk about fast fashion, is it the wastefulness or the quality that’s the main issue?
It’s a bit of both. Overall quality in the industry has diminished. Even brands that aren’t classified as fast fashion tend to mass produce using plastic-based materials, releasing new collections every week rather than a few times a year. Everything’s trend-driven, with heavy reliance on discounts and sales. Even premium brands, in my view, can contribute to unsustainable mass consumption.
Are there any brands you still support, or have you completely moved to buying secondhand?
I made a personal decision about three years ago not to buy new clothing, and since then , I’ve only bought secondhand. But I don’t want this to be about being perfect and ostracizing people—it’s about encouraging everyone to make small changes that add up over time.
I’m very much an in-person shopper. I have a big thing about feeling the fabric and checking the fit of clothing. I enjoy charity shopping—it’s almost like a hobby and a creative outlet for me.
Looking ahead five or ten years, what’s the big vision for Della Yellow?
The dream is for Della Yellow to be synonymous with circular fashion. In the next year, we’re hoping to complete a pilot scheme clothing brand—details are under NDA for now. Once we prove there’s consumer demand, we plan to license the app to multiple brands. This approach allows the market to leverage existing customer bases while offering an affordable, scalable repair service that upskills consumers.
And what does a society built on circular fashion look like to you?
Today, our culture is very much “take, use, and bin.” Imagine instead a society where circularity is second nature—where you have the skills to repair, customize, and even completely reimagine what you wear. It means being self-sufficient rather than relying on large corporations. Plus, there’s a lot of creativity in making your own style choices, rather than just picking what’s on the rack. Whether it’s resale, rental, repair, or customization, there are so many circular options that challenge the conventional norms.
Before we wrap up, do you have any advice for founders or recent graduates looking to start their own business?
One piece of advice that has always stuck with me is this: if you’re proud of your launch, you’ve launched too late. It’s about putting something out there—even if it’s imperfect—and then getting feedback to iterate. There’s a lot of fear about being embarrassed, but honestly, no one cares as much as you think. Your first idea isn’t going to be the final product. Expect to pivot multiple times until you really hit on something people want. So, step out of your comfort zone and just do it.
Finally, do you have a favorite modification or repair that you’ve done?
I was on the tube last week wearing my maroon Nike running leggings—back from when I was in sixth form—and they had a hole in the knee from a fall a few years ago. Eventually I learned how to darn the hole to fix it - basically, you weave a crisscross of threads to cover the gap, creating a patch. A lady next to me was so curious, asking, “how did you do that?” and complimented me on it. It was really sweet—she was really enthusiastic, and admitted she’d tried to learn before but couldn’t quite get it. That moment reminded me how personal and meaningful it is to learn and apply a skill yourself. Now, those leggings feel important—I really don’t want to get rid of them because they carry an emotional attachment, despite being just a piece of clothing.
