Kai: an AI personal trainer you just talk to

Most fitness apps ask you to type between sets, search a food database for "adobo, home-style", and copy numbers from your watch. People stop logging long before they stop training. Kai's promise is in its headline: just talk, and Kai does the logging.

Kai is an AI personal trainer and calorie tracker for Android, in a closed beta with invite keys. An iPhone version is listed as coming soon.

The product problem

Logging is the habit that makes coaching possible, so it has to cost almost nothing. Kai had to:

• log a set before you rack the bar, without unlocking a form;
• understand meals the way people describe them, Filipino favorites included;
• take calories burned from a watch without asking the user to copy anything;
• coach from real history, and say clearly what is an estimate.

Your voice is the whole interface

Tap the mic and say "Bench 80 for 8", then "Same again". Common gym phrases are understood right on the phone, so the set is in immediately, and everything else goes to Kai's AI, which knows the workout in progress. Meals work the same way: "Chicken adobo with two cups of rice" becomes items with portions, calories, and macros, in English or Taglish.

Corrections are part of the conversation

"Actually it was one cup" changes the portion and the totals follow. "Undo that" undoes the last thing Kai did. Nobody digs through a history screen to edit a row, and every change shows up as a card so you can see what happened.

Snap your plate

One photo of a plate becomes a logged meal: each item found, its portion estimated, and protein, carbs, fat, and fiber added to the day. The site is direct about the limits: photo calories are estimates, and Kai shows every item so you can see what it counted.

Your watch already knows

A Galaxy Watch syncs to Samsung Health, Samsung Health shares with Health Connect, and Kai reads it once you say yes. Calories burned land in the day's budget on their own, and meals logged in Kai are written back to Health Connect so other health apps can see them. You pick exactly what Kai can read.

A coach that remembers every rep

Because everything is logged, Kai can suggest the next set from how recent sessions went, say what is left to eat today, run a rest timer by voice, build a plan from one conversation, and notice new records. Answers come from your own logs.

Privacy written as product rules

The privacy section reads like a feature list: you choose what syncs, data is private by default, everything can be deleted in one tap, and Kai offers fitness and nutrition guidance, not medical advice.

The website

The site is dark with a lime accent. Its hero is an interactive orb that morphs into objects as you tap them, beside live-looking cards for calories burned and logged sets. A numbered side index takes the reader through eleven short sections, from "Say it" and "Voice" to "Privacy" and "Get Kai".

What the work reinforced

1. Make the fastest path local. Everyday phrases resolve on the phone, so logging never waits.
2. Show what the AI counted. Estimates are visible per item, and easy to correct out loud.
3. Ask before syncing health data. Consent is a screen, not a clause.

Continuing work

Kai is in a closed Android beta, with an iPhone waitlist. This story will be updated as the beta opens. If you are designing an AI product, decide early which answers must be instant and which can take a second, and build the instant ones without a network.