Everything you need to write about Djensur

press release

A whole year in hospital, and yet Niko (24) built the app that puts you on the big screen next to your idol

Joure, the Netherlands, September 2026

Niko Zeldenthuis (24) from Joure was born with the rare disease DADA2. He was only diagnosed at eleven, purely by chance: his doctor was at a conference in America and spoke with another doctor who had just identified a new disease, and it turned out to be exactly his. He was the seventh patient in the world to be diagnosed with DADA2. DADA2 is a serious rare condition that causes a wide range of symptoms: DADA is the protein this disease leaves you short of, and it normally has an anti-inflammatory effect. You can imagine how varied and dangerous the complications get once that protein is missing. "Inflammation is a very broad term, and it felt like my body was collecting every variant of it," says Niko.

In 2023 he had no choice but to undergo a stem cell transplant: the only way to actually get rid of his disease. The expectation was a hospital stay of four to six weeks. On 19 October 2023 he was admitted to UMC Utrecht. But unfortunately, the first transplant failed. He dealt with viruses, high fevers and serious complications, and spent two days in an induced coma, a period in which it was not certain he would wake up again. For Niko it was one of the hardest periods of his life, and for his parents it was no different. After chemotherapy came a second transplant, with stem cells from a new donor, and that time it finally worked.

What happened to his blood that year is remarkable in itself: within twelve months, Niko had three different blood types. First he simply had his own. Then, once the first donor's stem cells started producing his blood, he had that donor's type. That transplant then failed to take, which meant a new stem cell transplant, with another new donor. That second transplant eventually gave him his third blood type. "It is bizarre how far science has come with this," says Niko, who is still grateful for it.

Only on 18 February 2024 could he go home, and even after that came a number of readmissions because of complications. In total the whole process took about a year, far longer than the four to six weeks originally expected. Thanks to the second stem cell transplant, Niko is now cured. "I am still incredibly grateful to my stem cell donors and my blood donors. Without them I would not be here. Giving blood costs very little, and it can mean as much for someone else as it meant for me," he says.

During his treatment he made a TikTok video while he had to inhale nebuliser medication. Visually, the result was a young man left bald by chemotherapy who looked like he was "vaping" his medication, set to the song Appelmint Puur by Broederliefde (a song that happens to be about vaping). He made the video purely as a joke, but it suddenly got 1.8 million views! He ended up being recognised on the street because of it. In the months after that he just kept posting, and he also went live: he consistently pulled in around a million views a week. His fragile immune system kept most visitors away, but in those livestreams people showed up for him. That is how he built a network that got him through it, without ever meeting anyone in person. He deactivated his account, chemogieren, later on; at home he was too tired for it.

That time at home also gave him something else: room to think. In those months he thought an app concept all the way through. When he started feeling better, he actually built it: Djensur, a free app that shows you yourself dancing live on a stage, right next to the dancer you want to learn from.

"Dance is fun to watch, and the people around it are often super positive and motivated. That makes me happy," says Niko. That is the energy he wanted to capture in an app.

Here is how it works. You pick a dance video, anything from your own upload to a TikTok routine, a K-pop cover or the homework from your dance class, and Djensur cuts you out of your own room live. You see yourself standing right next to that dancer, the same step at the same moment. Stuck on a tricky bit? Loop it with one tap, and that exact section plays as many times as you like, with no rewinding by hand. The library is practically endless: you decide what goes in it.

The best part happens on the TV. Plug in your phone, and you are standing life size on your own stage with lighting and a set, right next to the dancer you want to get to know. Anyone who has ever danced in front of the couch with a dance game recognises the feeling instantly: except now it is your own choice of choreography, with your favourite dancer beside you.

Want to share a choreography of your own? Post it to the Community: anyone can stand next to it on their own stage while they practise it, and your name stays visible on it. You can keep it private too, or share it with one friend. The other way around, you can take a clip from your favourite choreographer or influencer and put it next to you on stage. Nail it, and you post it on TikTok: your idol might even repost your joint dance!

For dance teachers, Djensur has a class mode. A teacher records the choreography once, in the studio or just at home in the living room: her background disappears and she is standing on the same stage. She sets that recording as homework for her class, and every student can then practise it as often as they like, next to her on stage, on the TV or phone at home. That also lets the teacher see exactly who has been practising.

Djensur is on the App Store and on the Play Store, and it is free right now, with no ads. "I am launching for free because I worked on this for a long time and I do not think I should throw a paywall on it right away. I enjoy giving people a great experience," he says.

Niko is doing really well now, and he is proud that Djensur is finally here. Do you know someone who dances, or someone who simply has to read this? Send it their way. That is how Djensur finds the people it was made for.

About Djensur

Djensur is a dance practice app by Niko Zeldenthuis from Joure, the Netherlands. The app cuts you out of your room live and puts you next to the dancer of the video you pick, on a virtual stage. Available on the App Store and Google Play, free right now. Take a look at djensur.com.

The facts

Name

Niko Zeldenthuis

Age

24

Lives in

Joure, Friesland, the Netherlands

Education

mbo 4 e-commerce (Dutch vocational degree)

Building Djensur

Since 2024, started during his recovery.

App Store

Since 12 August 2026

Google Play

Since 3 September 2026

Price

Free right now, no ads

Works on

iPhone from iOS 15, and Android phones from around 2023 onwards

Languages

Dutch and English

What the app does

Cuts you out of your room live and puts you next to the dancer of your own video on a virtual stage. Slow-down, loop a section, and one cable to the TV. Dance teachers can create a class and assign homework.

One honest limit

The app wants one dancer in frame per video: solo clips and tutorials work, a group recording does not yet.

Privacy

Your live camera feed is processed on your own device and never uploaded.

Three quotes

Said by Niko in these words, free to use with his name attached.

Images and downloads

Free to use with a piece about Djensur. The demo clip shows in eleven seconds what the app does: an ordinary room dissolves and the dancer is standing on the stage.

High resolution photos of Niko will follow on this page shortly. Need one now, or a demonstration on camera? Email, and it arrives the same day.

Press contact

Niko ZeldenthuisMaker of Djensur

niko.zeldenthuis@gmail.com

Available for interviews (English or Dutch) and a live demo, in the Netherlands or over a video call, at short notice too.

Trying it yourself takes a minute: get the app on your phone, put it down in the living room, and you are standing next to the dancer.

On Android, Djensur looks best on a phone from 2023 or newer. On an older phone your image lags a little, and the app simply tells you so.