Build on a person’s numbers.

What you can build

Keely turns a person’s Polar Loop into four daily numbers, computed on their iPhone: Recovery, Load, Stress and Sleep, with HRV, resting heart rate, breathing rate, skin temperature, sleep stages and workouts behind them. The API gives your app those numbers for the people who connect it, so it can know the person it serves:

• Mornings. Each morning’s Recovery (0–100 %, against the person’s own 30-night normal), what moved it, and the night behind it: HRV, resting heart rate, breathing rate, skin temperature, sleep stages, sleep against need, and regularity.
• Training. Each day’s Load and its target range, time in heart-rate zones, Balance (this week against the three before), and every workout with its sport, times, Load, heart rate and zones.
• Stress. Each day’s averages (day, night, and while still), minutes at each level, and the moments that stood out.
• The journal. What the person noted, as tags over time windows, and, when they ask your app to, entries your app adds. Only while they share their journal in the Keely app.

Three things hold for everything the API answers:

• Summaries only, never raw heart data. Heart-rate readings and beat intervals never leave the person’s iPhone, and no endpoint returns them. The finest grain is a night, a day, a workout, or a stress moment.
• The person chooses what you get. They tick scopes on the consent page, and they can narrow or end them at any time in the Keely app or at meetkeely.com/assistants.
• Nothing is made up. What isn’t recorded is null, with a reason where there is one. What you’re not allowed to read is an error, never an empty answer. Every answer says when its data was last current (as_of) and links to how every number is computed.

Quickstart

Once your app is registered and you have its client_id, five steps take it from a person’s consent to their morning. Until Keely approves the app, the person is you: a new app connects only its developer’s account.

1. Send the person to authorize. Make a PKCE code_verifier, its code_challenge and a state, and open the authorization endpoint. The person signs in with their Keely account, ticks what your app may read, and comes back to your redirect_uri with code and state. Authorization has every parameter.

   https://zndhrjuvjoxbcdmwzeim.supabase.co/auth/v1/oauth/authorize
     ?client_id=YOUR_CLIENT_ID
     &redirect_uri=https://example.com/callback
     &response_type=code
     &code_challenge=CODE_CHALLENGE
     &code_challenge_method=S256
     &state=STATE
     &scope=email

2. Exchange the code for tokens. A confidential client authenticates with its secret; a public client leaves out -u and sends -d client_id=YOUR_CLIENT_ID instead. The answer holds an access_token good for an hour and a refresh_token.

   curl -X POST https://zndhrjuvjoxbcdmwzeim.supabase.co/auth/v1/oauth/token \
     -u "YOUR_CLIENT_ID:YOUR_CLIENT_SECRET" \
     -d grant_type=authorization_code \
     -d code=CODE \
     -d redirect_uri=https://example.com/callback \
     -d code_verifier=CODE_VERIFIER

3. Read who connected, and what they allowed. person_id is your key for the person, and scopes is what they ticked, which may be less than you asked for. GET /v1/me.

   curl https://meetkeely.com/api/v1/me \
     -H "Authorization: Bearer ACCESS_TOKEN"

4. Read this morning. The latest morning and the day it began: Recovery with what moved it, the night, sleep, Load, stress and workouts, under the scopes the person allowed. GET /v1/days/latest.

   curl https://meetkeely.com/api/v1/days/latest \
     -H "Authorization: Bearer ACCESS_TOKEN"

5. Keep up. Poll the changes feed for what changed since your last read, once an hour or once a day, or subscribe to events and be told at once.

   curl "https://meetkeely.com/api/v1/changes?since=2026-09-27T06:00:00Z" \
     -H "Authorization: Bearer ACCESS_TOKEN"

Key facts

Base URL

https://meetkeely.com/api/v1

Sign-in

OAuth 2.1 with PKCE, on Keely’s authorization server

Permissions

Six scopes, chosen by the person on the consent page

Format

JSON; local dates, UTC times, units in field names

Reference

/openapi.json, OpenAPI 3.1

Register

meetkeely.com/developers/apps

Cost

Free

Questions