For children · Apple Watch · iOS

What if you saw
the wave coming?

Most meltdowns are predictable two to four minutes before they erupt. Keel reads your child's nervous system in real time and helps them ride it out, gently, with you.

Join the waitlist How it works
The idea

An even keel is built below the surface.

The keel of a ship runs fully underwater. Silent. Invisible. Doing its most important work where no one can see. A ship on an even keel isn't still, it's moving through wind and waves. But the keel keeps it balanced. Hard to knock over. Quick to right itself when it tips.

That's what Keel does for your child. Not sedation. Not suppression. Regulation. The ability to move through a difficult world without capsizing.

It doesn't flash or alert or demand attention. It works beneath the surface, feeling the wave two minutes before anyone else can see it. So when the storm comes at school, in the car, at the dinner table, your child has already started to steady. And you're already there with them.

WATERLINE the keel FULLY SUBMERGED
How it works

The Apple watch reads what no one else can see. 

01

Learn the baseline

Seven days of silent observation. Keel learns your child's unique HRV patterns; morning, afternoon, school day, after-school. Not population averages. Theirs.

02

Feel the signal

A continuous haptic wave on the wrist; soft, submerged, invisible to anyone nearby. It reflects their physiological state in real time. Softer means calmer. Stronger means something is building.

03

Find even keel

When the wave builds, breathing tools activate. The haptic rhythm guides the breath. The child follows the wrist. Their body follows their breath. The wave softens. They feel themselves arrive.

A vocabulary spoken on the wrist.

Six haptic states. No words required. Children learn them in days; parents read them at a glance.

01 · Green

Even keel

Silence as signal. The watch goes quiet so quiet means safe.

02 · Yellow

Rolling wave

A slow swell on the wrist. Eight-second loop. An invitation, not an alarm.

03 · Red

Heavy weather

A continuous wave that intensifies with the score. Stays until the body settles.

04 · Breathing

Drop anchor

Resonance-frequency cadence. The wrist breathes; the body follows. Eyes can stay closed.

05 · Recovery

You came back

A sunburst on the wrist when the body — not behavior — confirms the return. A small, real win.

06 · Mirror

I'm with you

When you breathe alongside your child, your wrist sends a soft pulse. Presence at any distance.

Signal states

Three states. One wrist.

Keel runs continuously and quietly. No notifications until they matter. The same wave reads differently on each surface and none of them shout.

Green · Parent today

Even keel.

HRV within baseline. Heart rate steady. Nothing fires on the watch. Silence means safe, and the child learns that silence means something. Your phone shows one short paragraph and a trend line. Quiet awareness, by default.

Haptic: none · Arc: resting

Yellow · Parent alert

Building seas.

HRV dropping, heart rate trending. A slow rolling wave begins on the wrist; gentle, calibrated to the child's breathing cadence. On your phone, a short script with three options. An invitation, not an alarm.

Haptic: slow wave · Arc: amber pulse

Red · Child sky & sun

Heavy weather.

Significant deviation. The wave intensifies with the score; breathing tools surface. Your child sees weather and a sun, never a number, never a label. Their language: "big feelings." Stays open until their body, not a tap, confirms recovery.

Haptic: continuous wave · Arc: red · Parent notified

For the child

They feel it
before they see it.
That's the point.

  • A gentle wave on the wrist that mirrors their nervous system in real time
  • Haptic-guided breathing that works with eyes closed, in classrooms, in restaurants, anywhere
  • A celebration signal when their body, not their behavior, confirms recovery
  • Private. Non-stigmatizing. Nobody else knows what the watch is doing
  • Age-adaptive: simple and concrete for younger children, direct biofeedback framing for older
For the parent

See the weather
before the storm
arrives on shore.

  • Morning intelligence report: today's baseline and predicted sensitivity before school
  • Real-time state indicator — Green, Yellow, Red — on your phone
  • Tier 1 alert when Red begins. Tier 2 alert only if duration exceeds the recovery window
  • Mirror mode: join the intervention, breathe alongside them, send a presence signal to their wrist
  • Episode log with full biometric timeline, shareable with therapists
Built on research

The science is as deep as the keel.

HRV drops before dysregulation peaks. Not after. The pre-escalation window is real, typically 2 to 4 minutes, and measurable from a wrist-worn sensor. Keel operates in that window.

Haptic-guided resonance frequency breathing outperforms visual-only guidance for HRV recovery. Children breathe at a different resonance frequency than adults. At 7 to 9 breaths per minute versus 5.5 to 6.5. Keel adjusts automatically by age.

Every child's recovery window is different. Keel learns it from their data, not population averages. After ten confirmed events, your child's personal recovery baseline is established. The system calibrates to them, not to the mean.

2–4

Minutes of pre-escalation biometric signal before behavioral expression

7 days

Passive calibration before any alerts fire. This is your child's baseline, not anyone else's

0

Alerts during calibration. Keel watches quietly before it speaks

Pricing

Less than one therapy session. Every month.

Keel works between the sessions... in classrooms, at dinner tables, on the way to school. Priced accordingly.

30 days free. No credit card required. Keel takes 7 days to calibrate to your child's baseline. We don't ask for payment until you've seen it work.

Monthly

$19 .99 / mo

Billed monthly. Cancel anytime.

Full access to all features. No long-term commitment.

  • One child profile
  • 7-day baseline calibration
  • Continuous HRV biofeedback
  • Parent real-time dashboard
  • Episode log and therapist export
  • 30-day free trial included
Start free trial

Free trial

$0 / 30 days

No card needed. Full access.

Every plan starts here. See a full calibration cycle and your first real event before you decide.

  • Full access to all features
  • Complete 7-day calibration
  • No credit card required
  • Choose your plan on day 30
  • No automatic charge if you don't
Join waitlist

Apple Watch Series 4 or later required · iOS 16+ · Keel does not replace professional medical advice, therapy, or clinical care.

Early access

Give them
an even keel.

Keel is in development. We're onboarding a few families at a time. Join the list and we'll hold your spot in the next wave.

For parents, therapists, and educators. No spam. Unsubscribe anytime. Early access includes 30-day free trial.