Privacy policy
Last updated 24 October 2026
The short version. Chalk keeps your training, body and food logs so it can show your progress and coach you. There are no ads, no analytics or tracking tools, and your data is never sold. The AI coach sends the relevant parts of your log to Anthropic to write its replies. You decide who sees your workouts, and you can download or delete everything from inside the app.
- Who runs Chalk
- What Chalk collects
- The AI coach
- Who can see what
- Companies that help run Chalk
- Why Chalk is allowed to use it
- How long it's kept
- Your rights
- Children
- Security
- Changes and contact
1. Who runs Chalk
Chalk is made by Ross Harrison, a sole trader in the United Kingdom, trading as Chalk. He's the controller of your personal data under UK data protection law (the UK GDPR and the Data Protection Act 2018), and the EU GDPR where it applies.
Contact: support@chalkfitness.co.uk
2. What Chalk collects
Only what you give it, or what it needs to run the features you use.
| What | Details | Why |
|---|---|---|
| Account | Your email address, or your Sign in with Apple identifier (Apple may give a private relay address instead of your real email). Display name, username and profile picture if you add them. | To sign you in and let friends recognise you. |
| Training | Workouts, sets, weights, reps, cardio, stretches, routines, notes, targets, your training goals and experience, and photos you add to a workout. | The core of the app: your history, PBs, charts and next targets. |
| Body and health | Weigh-ins, body measurements, progress photos, and muscles you flag as sore or injured. | To track your progress and adjust your training. You only enter this if you want to. |
| Food (Chalk Pro) | Your food log, recipes, meal plans and nutrition targets, plus the details you enter to work out targets (sex, age, height, weight, training days and goal). | To track what you eat against your targets. |
| Social | Friends, friend requests, likes, comments, challenges, shared workouts with training partners, your level and XP, and any reports or blocks you make. | The social features, and keeping them safe. |
| Subscription | Whether you have Chalk Pro, which plan, and when it renews or ends. Apple takes the payment; Chalk never sees your card details. | To switch Pro on and off. |
| Notifications | A push notification token for your phone, if you allow notifications. | To tell you about likes, comments, friend requests and similar. |
| Strava | If you connect Strava: access tokens and the activities Chalk imports (time, distance, type and similar). | To bring your runs and rides into your history. |
| Usage limits | How many coach reviews and chat messages you've used today. | To apply the daily coach limits. |
Chalk doesn't use advertising, analytics or tracking tools, and doesn't follow you across other apps or websites. Like any online service, the servers it uses see your IP address when your phone connects, and keep standard technical logs for a short time.
The camera is only used when you choose to take a photo or scan a barcode. Barcodes are read on your phone. The Live Activity on your Lock Screen during a workout is created on your phone and isn't sent anywhere.
3. The AI coach
When you ask for a workout review, chat with the coach, estimate a meal or get a review of your day's eating, Chalk sends the relevant part of your log to Anthropic, whose Claude models write the reply. That can include recent workouts, targets and routines, weigh-ins and measurements, muscles you've flagged, your food log and your nutrition targets, plus a meal photo or description if you're estimating a meal.
Meal and nutrition label photos are sent only to get the estimate. Chalk doesn't store them. Under Anthropic's commercial terms, data sent through its API isn't used to train its models.
The coach gives general training and nutrition guidance. It isn't medical advice.
4. Who can see what
You choose in Settings → Privacy:
- Everyone: anyone on Chalk can see your workouts on the Everyone feed, and like or comment on them.
- Friends (the default): only your friends see your workouts.
- Private: nobody sees your workouts or level, friends included.
Whatever you choose, your display name, username and profile picture can be seen by people you interact with, and someone who types your exact username can find you and send a friend request. Your comments are seen by anyone who can see the workout you commented on.
Your body measurements, progress photos, food log and coach conversations are never shown to other people. Imported Strava activities are only shown to you.
When you train with a partner in Chalk, the sets each of you logs for the other go into the other person's history, and you can see each other's sets for that workout.
5. Companies that help run Chalk
These companies process data on Chalk's behalf, only for the purposes below:
- Supabase: the database, sign-in, photo storage and server functions. Your data is stored on Supabase servers in Europe.
- Anthropic (USA): the AI coach, as described above.
- RevenueCat (USA): keeps track of your App Store subscription, linked to your Chalk account ID rather than your name or email.
- Apple: Sign in with Apple, App Store payments and push notifications.
- Resend (USA): sends sign-in code emails.
- Expo (USA): delivers app updates to your phone.
- Open Food Facts (France): when you scan a barcode or search for a food, your phone sends the barcode or search words to Open Food Facts' public database. Nothing else about you is sent.
- Strava (USA): only if you connect it.
Where data goes outside the UK, it's protected by UK adequacy regulations or standard data protection clauses in Chalk's agreements with these companies.
6. Why Chalk is allowed to use it
- To provide the app you signed up for (contract): your account, logs, history, coach and social features.
- Your consent: body and health details, photos, notifications and Strava. These are optional, and you can delete them or switch them off at any time.
- Legitimate interests: keeping Chalk safe and working, for example acting on reports, preventing abuse and fixing problems.
7. How long it's kept
Your data is kept while you have a Chalk account. When you delete your account (Settings → Account → Delete account), everything is deleted straight away: your logs, photos, social activity and connections, and Strava access is revoked. Copies may remain in backups for a short time until they're overwritten.
If you reported something, or someone reported something you posted, a copy of the reported content is kept so it can be reviewed, even if the original is deleted.
8. Your rights
You can:
- Download your data: Settings → Your data gives you your workouts as a spreadsheet (CSV) and a full backup (JSON).
- Correct it: edit workouts, body entries, food and your profile in the app.
- Delete it: delete individual entries, or your whole account in Settings → Account.
- Object, restrict or withdraw consent, or ask for anything else about your data, by emailing support@chalkfitness.co.uk. You'll get a reply within a month.
If you're unhappy with how your data is handled, you can complain to the UK Information Commissioner's Office at ico.org.uk, or to the data protection authority where you live.
9. Children
Chalk isn't meant for children under 13, and doesn't knowingly collect their data. If you think a child under 13 is using Chalk, email support and the account will be deleted.
10. Security
Data is encrypted between your phone and Chalk's servers. Database rules stop anyone reading another person's data unless that person has shared it with them. Progress photos are stored privately and only shown to you through short-lived links.
11. Changes and contact
If this policy changes, the new version will appear here with a new date. If a change affects how your data is used, you'll be told in the app first. Questions: support@chalkfitness.co.uk.