Getting started

For the stress score, yes. Mochi builds that score from heart-rate variability recorded by your Apple Watch and read through Apple Health, so with no watch there is no HRV to read and no score.

Everything else works without one: logging water and caffeine, steps, daylight, noise, mindfulness, and notifications. If you do not have a watch, Mochi still works as a daily log of those things, and the stress score is the part that stays empty. If you do have one, wear it through the day and the readings arrive on their own.

iOS 17.6 or later on the iPhone, and watchOS 10.6 or later on the Apple Watch. The current app version is 1.3.2.

You can check both in the Settings app: iOS on the iPhone, and watchOS either on the watch itself or through the Watch app on your iPhone. Updates are in the same place.

The iPhone side runs as soon as you meet the iOS requirement. The stress score also needs a watch on watchOS 10.6 or later. Any Apple Watch that can run that will do — we do not publish a list of models, because the watchOS version is what decides, not the model name. If your watch cannot be updated that far, there will be no stress score. That cutoff is Apple's, and it is not something we can work around.

Heart-rate variability matters most: Mochi reads it from Apple Health, and the stress score is built from it. Alongside it, Mochi shows steps, daylight, noise and mindfulness in the rest of the day view. Health permissions are granted category by category, so you can allow heart-rate variability and refuse anything else.

You change them in the Health app on your iPhone: open your profile, find Mochi in the list of apps that have asked for access, and switch the categories on or off.

If you declined something at first run, that is where you turn it back on. Health data never leaves your device — there is no health-data server.

On day one there may be nothing to show. Apple Watch records HRV automatically every few hours, not continuously, and the data can reach Health with a delay, so your first reading appears when your watch takes one. Until then Mochi shows "No reading yet" rather than guessing a number.

The score is measured against your own baseline, so it needs a run of your own readings before it means much. Early scores rest on thin data. We cannot put an exact number of days on it, because that depends on how often you wear the watch. It reflects your own pattern, and it is not a diagnosis.

Not on demand. Apple Watch records HRV automatically every few hours, and the watch decides when to sample — no app can ask it for one.

What tends to help: open Mindfulness (Breathe) on the watch and run a session of at least three minutes, with the watch snug on your wrist and you sitting still. Then lock and unlock your iPhone once to nudge Health into syncing, and wait about a minute.

Apple Watch data can arrive with a delay, so give it a little time before checking Mochi again.