You can put Meridian on your phone now.

For most of this year Meridian has been a thing you visited. You opened a browser, you signed in, you looked. It worked, and it was never quite right. The moments this app is built for do not happen at a desk. They happen at eleven at night when you cannot work out why a good week left you flattened, and in the first minute after waking when the day is still undecided.

This week it became a thing you carry. The Meridian app for iPhone is in beta.

The change that matters most is not the icon on your Home Screen. It is that the app reads Apple Health natively, and keeps reading it in the background. Your nights and your days arrive on their own. If you wear an Apple Watch, a Garmin, a Coros, an Amazfit, anything that writes to Apple Health, it now reaches Meridian without you lifting a finger. An Oura ring or a WHOOP band connects directly inside the app, in the setup flow, before you have finished signing up.

Until now, getting a watch into Meridian meant installing a shortcut, pasting a code, and trusting a chain of steps you had no way to check. That path is retired. Anyone still using it keeps it working, but nobody new has to meet it. Removing a setup step is not a glamorous launch note. It is the difference between a product people try and a product people keep.

A mirror you have to remember to visit is a mirror you stop visiting.

What else shipped this week

• Setup starts with your device, not a formThe new wizard asks what you wear and connects it in place. A three-hour partial night no longer counts as a full night, which was quietly distorting the first week of anyone who slept badly at the start. Invitations can now carry a language, so an Italian or French reader lands in their own rather than in English.
• Two new senses, and neither one speaksYour nightly breathing rate and your blood oxygen now feed the model, with deep sleep and a first version of experience capture alongside them. You will not see any of them. They have no chip on your Today page and cannot appear as a weekly mover. They reach you only inside a finding that has survived the same statistical referee every other pattern has to survive. If they never earn that, you will never know they were there.
• Sleep and mood now says what it actually knowsWhere the app used to show a fixed placeholder, it now tells you one of two honest things: this is not testable yet, and here is how many of your nights have a check-in beside them, or it has been tested and your sleep and your mood have not moved together so far. A dimension you feel, rather than one your wearable records, is also now guaranteed a place at the top of Patterns.
• The echo above the writing field is goneFor a few days Meridian showed you something you had written before, directly above the empty box where you were about to write today. It looked thoughtful. It was not. Nothing should hand a person their own past words while they are still finding this evening’s. We removed the surface and the machinery behind it.
• Fewer cards, and better onesThe focus card had been printing a keep-logging message to accounts holding a year of data. It is now gated on something actually having moved, so an empty week produces silence rather than filler. The engine also learned to correct for the slow rhythms underneath a person’s data, the ones that repeat across weeks rather than days, so the shape of a month does not get mistaken for a pattern in your Tuesdays.

Why reading the night automatically matters

There is real evidence that the body’s night carries information about the felt life. Lee and colleagues, writing in npj Digital Medicine in 2024, showed that sleep and circadian features taken from a wrist wearable could anticipate mood episodes days ahead.

Read the paper properly, though, and the caution is in the sample. It followed 168 people already diagnosed with a mood disorder, and its strongest performance was for manic and hypomanic episodes. That is a clinical population being watched for clinical events. It is not you, having an ordinary Tuesday. The honest sentence is that wearable sleep patterns carried real signal about mood in that study, and nothing more.

But notice what the study needed to find anything at all: continuous, unglamorous, every-night data. Not the nights someone remembered to sync. That is the whole argument for a native app reading Health in the background, and it is why we spent a launch on plumbing rather than on a new screen. The signal in this kind of work does not live in any single night. It lives in the run of them, including the boring ones, and any setup step that makes a person skip a week is quietly taking evidence away from their own model.

Which is also why the two new senses went in dark. The literature says this territory is worth exploring, so breathing and blood oxygen went into the model. The literature does not license us to tell you what your breathing means, so they went in silent. Your own data, tested against your own history, is the only bridge between those two positions. If a link is really there in your life, you will read it in plain language. If it is not, the quiet is the correct answer.

Where this is going

The beta is on iPhone, and it is opening in small waves rather than all at once, because we would rather sit with a handful of people properly than watch a crowd bounce. Meridian still runs in a browser and will keep doing so. Android is not there yet, and I would rather say that plainly than imply a date I cannot hold.

The next stretch is about time rather than features. A second group is being put together now, and the question we care about is not how many signals the model can hold but how many are still standing after a real month of skipped days, late nights and uncharged rings. Everything above is in service of that: the fewer steps between your life and the model, the more honest the answer at the end of the month.

If a mirror that measures more than it says sounds like something you would use, requesting access is the way in.

Written by Davide Tempesta, Founder of Meridian.