The $210 App That Became a Million Dollar Company Overnight
How three developers in China built Demumu for $210, went viral asking 'Are you dead?', and sparked a global conversation about loneliness and solo living.
In June 2025, three developers at a small company called Moonscape Technologies in Zhengzhou, China spent about 1,500 yuan — roughly $210 — building an app. It sat quietly in the App Store for months.
Then, in January 2026, it became the #1 paid app in China. Within days, it was topping charts in the US, UK, Canada, and Australia. Sixty investors came knocking. A 10% stake reportedly jumped from 1 million yuan to nearly 10 million yuan in three days.
The app's name: Sǐ le ma. "Are you dead?"
The Idea Was Absurdly Simple
The app does almost nothing. You open it once a day and tap a button to confirm you're okay. If you don't tap for a couple of days, it sends an email to up to two emergency contacts you've designated. No account. No subscription. No tracking. Just a button, and a backup plan.
The developers — all born after 1995 — weren't trying to build a business. They were solving a problem they saw around them: in a country with 125 million single-person households, what happens when something goes wrong and nobody notices?
The Name That Launched a Thousand Headlines
The original Chinese name was a deliberate provocation. Sǐ le ma riffs on Ē le ma — "Are you hungry?" — the slogan of China's biggest food delivery platform. Same cadence, darker question.
It was uncomfortable. That was the point.
On Weibo, when the team announced they'd rename the app Demumu for global launch, users pushed back hard. One wrote: "Maybe some conservative people can't accept it, but it is helpful for safety purposes. It will make us unmarried people feel more at ease to spend our lives."
The bluntness wasn't a bug. It was the product.
Why It Hit So Hard
The dark humor got the clicks. But the reason people actually downloaded it — and kept it — was something quieter.
A 57-year-old former IT analyst in Texas described his daily check-in routine: feed the cat, tidy up, then tap the button. "It's kind of nice," he said. "It's almost like someone cares."
That quote — from a man who has people in his life, who isn't in crisis, who is simply living alone in modern America — explains everything. The app didn't go viral because it was technically impressive. It went viral because it named a fear that millions of people carry around and never say out loud.
The Wave That Followed
Within days of going viral, Demumu had inspired dozens of copycat apps. Investors flooded in. The category — quiet, underserved, slightly morbid — suddenly had everyone's attention.
It also sparked a broader conversation: check-in apps aren't just for the elderly. The primary demographic for these tools spans students, remote workers, solo travelers, and young adults living independently. Japan's government data showed over 1,000 people under 40 died alone at home in 2024, discovered more than eight days later.
The fear Demumu addressed isn't a senior issue. It's a modern life issue.
What the Story Means for Anyone Living Alone
Demumu proved something important: people want a simple, non-intrusive safety net. Not a medical device. Not a subscription service with a call center. Just a quiet app that asks a simple question every day, and notices if you stop answering.
That need existed long before Demumu. It'll exist long after.
CheckIn More: Built on the Same Idea, Taken Further
We started CheckIn More for the same reason the Demumu team built their app — because people living alone deserve a simple way to let someone know they're okay, and to know someone will notice if they're not.
We've taken the concept further: SMS text alerts (not just email), unlimited contacts, flexible scheduling, mood check-ins, an assistance button, and Android support. Same core promise — more ways to make it work for your actual life.
See how CheckIn More compares to Demumu →
All information current as of February 2026.
