Does Baku really work without internet?

Yes. After installing, you can put the phone in airplane mode and Baku runs exactly the same. The Gemma 4 model lives on your device. Voices are Apple's free natural voices, also on-device. The only network calls are App Store updates.

What model does it run?

Google Gemma 4 (a small, open-weight model), quantised and converted to Apple's Core ML format so it can run on the Neural Engine. Runs comfortably on iPhone 12 and newer; works on older devices but more slowly.

Is my child's data ever uploaded?

No. There is no analytics SDK, no crash reporter, no telemetry. Your child's name, age, favourite themes, and saved stories live in the app's local sandbox. They never leave the phone unless you explicitly export a story.

Why $5.99 instead of a subscription?

Because subscriptions for kids' content turn into a guilt loop. Pay once, keep it forever, including all future story themes and language updates. If the app ever stops being maintained, you still have it.

How are stories kept safe?

Three layers. First, kids never type — they only tap from a parent-curated wish list. Second, generation is constrained to bedtime themes (no horror, no death, no violence). Third, every sentence runs through a 12-language safety filter before being read aloud. If anything is flagged, Baku quietly regenerates.

Designed for 3–8. Younger kids enjoy the voice and the rhythm; older kids enjoy specific wishes ("a friendly dragon called Pip who likes mango"). It works in English, Simplified Chinese, and Spanish.

Will there be Android?

Maybe. iOS first because the Neural Engine is the easiest place to run on-device models well today. If enough Android parents ask, I'll port it — but I won't ship something slow.

April 25, 2026 • calm kids alternative · privacy · kids apps · on-device AI · no subscription

A Calm Kids Alternative That Doesn't Send Your Child's Voice to the Cloud

Why I stopped using Calm Kids for my daughter, and what I built instead — a fully on-device bedtime AI that costs $5.99 once and never phones home.

I subscribed to Calm Kids for almost a year. Then I read the privacy policy.

It is a beautiful product. The sleep meditations are professionally produced, the voice talent is calming, the illustrations are gorgeous. But I noticed three things that bothered me as a parent:

The annual cost ($69.99) renews automatically. After 12 months, my family had spent over $130 on bedtime audio.
The privacy policy permits “third-party analytics partners” to receive interaction data — including my daughter’s age and listening history.
If the app is ever acquired or shuts down, that data goes wherever the next owner takes it.

This isn’t a Calm Kids hit piece — it’s an honest review from a paying customer. Calm Kids is not unique here. Almost every kids’ AI app in 2026 has a similar architecture: voice in, story out, server-side, logged.

So I built the opposite. Here’s why and how.

The architecture that bothered me

A typical “AI bedtime story for kids” app works like this:

Child taps mic → recording uploads to cloud →
LLM generates story → text streams back →
TTS service reads story aloud (more cloud calls) →
all of the above is logged, often "to improve the model"

Each one of those arrows is a privacy decision the parent didn’t get to make.

The problem isn’t that any single company is malicious. It’s that:

Voice recordings of children are extremely sensitive.
Logs persist longer than the company sometimes does.
“Anonymized” voice data is well-documented to be re-identifiable.
COPPA-compliant doesn’t mean “private” — it means “the parent technically opted in via the EULA.”

What “on-device” actually means

I built Baku AI so the entire flow runs on the iPhone:

Child taps mic → Apple's on-device speech recognition →
text → on-device Gemma 4 (Google's open LLM) →
text → Apple's on-device speech synthesis →
audio plays. No network call at any step.

The first time you launch Baku, it downloads a ~1.5 GB Gemma 4 model from Hugging Face. That’s the only network event. After that, you can put the phone in airplane mode forever and Baku still works.

This is not a marketing claim — it’s testable. Open Charles Proxy, watch the network panel after the model finishes downloading, generate 10 stories, read your child to sleep. You’ll see zero outbound requests.

What that costs me as the developer

Building bedtime stories without a server costs me revenue:

No subscription. Without server costs, I can’t justify charging recurring revenue. Baku is $5.99 once, lifetime access. Optional $0.99/month unlocks “Personal Voice” (your own recorded voice reads stories) — but the core app needs no subscription.
No retargeting. I have no idea who my users are or what they’re doing. I can’t run conversion-optimized ads against my own audience.
No model improvement loop. Cloud apps get better when more users feed them data. Baku gets better when I (the developer) ship a new model version.
Larger app size. The on-device model is ~1.5 GB. That’s the trade-off.

I’m fine with all of those costs because I built this for my own kid first. The economics work out at independent-developer scale.

What you actually get

Compared to Calm Kids specifically:

	Calm Kids	Baku AI
Pricing	$69.99 / year	$5.99 once
Story content	Fixed library, professionally narrated	AI-generated, different every night
Personalization	Limited	Optional child profile (name, age, theme) — local only
Languages	English	English · 中文 · Spanish
Voice talent	Real humans	Apple’s natural voices (or your own via Personal Voice)
Network use	Always-on	First install only, then 100% offline
Data collection	Yes, per privacy policy	None, by architecture
Account	Required	None
Auto-renew	Yes	N/A
Works on plane	Limited	Yes
Sleep timer with screen-dim	Yes	Yes
Safety filter	Editorial review	12-language keyword filter + curated wishes

When Calm Kids is still the right choice

I want to be honest:

If you love the specific Calm voice talent, that’s irreplaceable. AI-generated narration in 2026 is good but not Calm-quality.
If you also use Calm yourself as an adult, the family bundle is reasonable.
If your child wants the same beloved story re-read 200 times, a fixed library wins. AI stories are different every time, which some kids love and some find unsettling.

What to ask yourself

Three questions to figure out whether on-device AI is for you:

Do I want a different story every night, or the same comforting story repeated? AI wins for variety, fixed libraries win for ritual.
Do I trust this app’s privacy policy enough to feed it my child’s voice for years? If you hesitate, “on-device” isn’t paranoia — it’s the conservative choice.
Am I willing to trade polish (professional voice talent) for control (zero data leaves the phone)? This is the actual trade-off.

If your answer to 2 and 3 is “yes,” try Baku AI for $5.99. If after a week it’s not right, I’ll personally help you pick a different app from my honest comparison post.

— Jingyang Ye, founder of Baku AI