A free AI companion for individuals, on iPhone and the web
Meet Yuyu, Serenio's AI companion. It listens first, remembers what matters to you, and helps you find your own words, the moment a feeling arrives.
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People who have tried Serenio across all its versions, as of August 2026.
Watch · 28 seconds
What Yuyu is like
Yuyu stays with the moment instead of rushing to fix it. Three things guide every reply.
Before any suggestion, Yuyu says back what it heard, so you feel understood rather than handled. Emotional accuracy, not generic comfort.
The people, hopes and worries you share carry from one conversation to the next. You can see, edit or forget any of it.
When something feels too heavy to hold alone, Yuyu gently points you toward people who can truly be there, with support lines one tap away.
Inside Serenio
Talk it through
Type, speak or share a photo. Yuyu replies in your language and picks up the thread from last time, so you never have to start from the beginning.
Something to try together
Each practice is a short, guided conversation adapted from cognitive behavioural therapy (CBT) and related approaches. Pick whatever fits the moment, and stop any time.
Journal
Write, speak or add a photo. Each day brings a question drawn from your own pages, and Yuyu reflects back what it notices, with one gentle question to take further.
Insights
Four weeks of your own days: how the weeks have felt, the thinking traps that keep appearing, what seemed to help, and what your journal returns to.
Your memory, your choice
Start with a note, in your own words, about what Yuyu should know. Everything else it remembers sits in one place, grouped into people, hopes, what helps and more. Nothing is hidden from you.
And a little more
The standard PHQ-9 and GAD-7 questions, with plain-language results you can follow over time. A snapshot, never a diagnosis.
Seven steps you write while things are calmer, for the moments they're not: what to notice, what helps, and who to reach.
Ask, and Yuyu writes you a letter drawn from what the two of you have talked about, signed with what it was written from.
Seal a note for a week or up to a year. When it opens, Yuyu adds how much has happened since, without ever reading your words.
Write it in the web appFive quiet minutes to close the week: the week in one word, what it actually held, one question, one small step, and a line for next Sunday.
In the web appBox or 4-7-8 breathing for one, three or five minutes, with gentle haptics you can follow with your eyes closed.
On iPhone
Get Serenio
For individuals, Serenio costs nothing. Use whichever fits your day, or both.
Talk, journal, breathe and see your patterns, with support lines one tap away on every screen.
Open it in any modern browser, on a computer, a tablet or an Android phone, and add it to your home screen.
Offering Serenio to a team, a university or a community? That's a paid partnership. See how it works.
How it works
An AI companion should be open about how it works. Here is the short version.
Crisis language is checked before Yuyu writes a word, in English, Chinese, Cantonese, Japanese and Korean. A second AI check looks for quieter signs.
Practices adapted from CBT, a safety plan based on Stanley and Brown, and the standard PHQ-9 and GAD-7 questions.
No ads and no selling your data. Microsoft and OpenAI, whose models power Yuyu, don't train on your conversations.
Yuyu is an AI, not a person and not a therapist. It doesn't diagnose, and it isn't an emergency service.
I once lost a friend after sharing my most hidden side. After that, I couldn't share my darker feelings with anyone close to me. Here, I can.
In Taiwan, mental-health resources still feel unfamiliar, and it's hard to find the right person to talk to. Serenio genuinely helped.
After work each day, I can say a few words to Serenio. A whole day of anxiety finally has somewhere to go.
I always thought of myself as a lonely person. Serenio is always there, patient and warm, listening to everything that weighs on me.
A note from Dave
I'm Dave, and Serenio began with helplessness. I watched my sister live with depression, and there were days I sat beside her hospital bed with everything I had to give and still no idea how to reach her. Caring about someone deeply, I learned, is not the same as knowing how to help them.
That helplessness is why Serenio exists. I don't believe emotional support should be a luxury, or something you only reach for once things have already broken. So we built something gentle and always there: a companion that listens the moment a feeling stirs, sits with it, and helps you find your own words for it. And we made it free for anyone who needs it.
A while after we launched, a man in his forties wrote to tell me Serenio had stayed with him through one of the lowest points of his life. Six months later he messaged again, just to say he was still here. I don't take a message like that lightly. It is the whole reason we keep going.
I get to do this with people I trust, psychologists, engineers and human-computer researchers across Hong Kong, Denmark, Canada and Taiwan, with the support of the Technical University of Denmark, Accelerace, Micro Grant and Beyond Beta. We're small on purpose, and we care about the human part before anything else.
Yes, for individuals. There's no subscription, no in-app purchase and no advertising, on iPhone or on the web. To keep it sustainable, Yuyu gently closes the day after 50 replies, and replies during a hard moment never count toward that. Organizations that want to offer Serenio to their people work with us on a paid partnership.
No. Yuyu is an AI, software built on large language models. It's designed to listen carefully and reply warmly, but no person is typing on the other side, and it isn't a therapist.
No. Serenio is a companion for everyday feelings. It doesn't diagnose or treat any condition, and it isn't a medical device. For diagnosis or treatment, please speak with a qualified professional.
Every message is checked for signs of crisis, and when there are signs of risk, Yuyu shows 24-hour support lines you can call with one tap. But Serenio is not an emergency service, and no one monitors conversations. If you are in danger, call 999 in Hong Kong or your local emergency number. You can also find support lines at any time on Serenio's support page, no account needed.
Your conversations belong to your account. We don't sell data or show ads, and Microsoft and OpenAI, whose models power Yuyu, don't use your conversations to train their models. Journal videos are made by Volcengine (ByteDance) in mainland China, and only if you ask for one. You can download everything, or delete your account, at any time. See where your words go.
Adults aged 18 and over. The iPhone app needs iOS 18 or later and is available in App Stores across Asia-Pacific. The web app works anywhere, in any modern browser, including on Android.
English, Traditional Chinese, Japanese and Korean. Yuyu replies in the language you write in, and in Traditional Chinese you can choose written Chinese or spoken Cantonese.
Looking after a team, a university or a community? Serenio for organizations is a paid partnership.
For organizations
