Welcome to the fourth issue of Side Hustle Lab. 🧪
In this new series, we share solo side-hustle cases we've recently discovered, break down in detail how each one works and how it makes money, and also tell you how we would build the same side hustle if it were us.
We hope this series can inspire you — from a fresh and fun angle — to find a side-hustle idea of your own!
Have you ever thought about this: if you live alone and something suddenly happened to you, would anyone know?
This seemingly heavy question was actually turned into an App — and at one point it sparked a huge amount of discussion online.
Today's case is exactly that App, which went viral earlier this year: Demumu (originally called "死了麼," roughly "Are You Dead Yet").
🚀 Side hustle: Demumu (死了麼)
The App's function is actually very single and clear: users need to regularly "check in" to signal they're okay.
If there's no response for a long time, the system notifies pre-set contacts. So it's a very simple "don't let me be forgotten" reminder tool.
💰 Revenue & the numbers
According to media reports, the App was co-founded by three post-'95 young people, developed part-time via remote collaboration, with a development cost of around RMB 1,000 (about HK$1,100 / TW$4,400).
It was free to download at first, then started RMB 1 paid downloads at the end of 2025, and rolled out an RMB 8 paid plan in early 2026.
The founders say the product has already started to "turn a profit" (though they haven't disclosed specific revenue figures). The team also once planned to sell 10% of its shares at around RMB 1 million, implying a valuation of about RMB 10 million (about HK$11M / TW$44M).
📝 What makes this side hustle special
The most special thing about this product is that, in an extremely minimal way, it validated a real and rarely-acknowledged need: the feeling of loneliness, and of being needed.
Even more interesting: this App doesn't only attract people who live alone. Plenty of young people — even though they don't actually need the App's function — try it out with a dark-humor mindset because it's a talking point and carries a bit of emotional resonance, and some even share it on social media.
So on the surface it's a functional tool, but in essence it's an "emotional product." And that is exactly what makes this case most worth thinking about. [We see a lot of potential side-hustle opportunities in it~ more on that below]
🛠️ Tools you would need to build this side hustle
If you want to build a similar model,
❤️ [Exclusive take] If it were me, how would I do it?
I would consider the following four extension directions:
1) Build a "lighter" version (to test the market fast)
For example, a simple check-in webpage, or a Telegram / WhatsApp bot, to first test whether anyone would actually use this.
2) Turn the "emotional product" into a "practical product"
To make the App more valuable, I would add:
3) Combine the "emotional product" with "social sharing"
If I wanted this kind of App to become more widespread, I would combine:
4) Turn the feature into a "content or traffic entry point"
Build a "Loneliness Index test" site, or a "solo-living tools collection," to drive traffic — then monetize further through content or referrals.
💡 [Bonus] Behind this case is actually a bigger trend
Demumu (死了麼) is just one example; the bigger trend is that the "solo economy" is growing fast.
You've probably noticed it too: the single population is rising, remote work is increasing, and small households / living alone are becoming more common.
All of these create new needs — including a sense of safety, companionship, efficiency, and convenience.
And every one of these needs can be productized — even turned into a side hustle!
After reading this case, will you start to wonder: are there some "needs that look tiny but that lots of people actually have" that still haven't been properly solved?
Feel free to reply directly to this email and tell us, or share your thoughts or questions with us — we'll answer and discuss them in upcoming issues of Side Hustle Lab!
Morning & Tiffany @AfterWork Startup
Slashing into entrepreneurship with you, opening up multiple income streams