Last updated: 6 October 2026
This policy explains how Callus (the "App") handles your information: what is collected, why, where it goes, how long it is kept, and the choices and rights you have. "We", "us" and "our" mean Leon Johnstone, the developer of the App. We are the controller of the personal data described here, except where this policy says Apple or another company acts independently.
In short:
Leon Johnstone
Flat 7, Danescroft, Brent Street
London NW4 2QH
United Kingdom
Email: support@callustraining.com
Each time the coach responds, the App sends a request to our server, which runs on Cloudflare. The server passes it to an AI model to write the response. A request can include:
AI providers. Coaching responses are generated by OpenAI. Share-video captions, and some older features, use Anthropic. A caption request sends only a text summary: your first name, the movement, what changed and what to work on next. It contains no images. These providers process the data to generate a response for us under their commercial API terms. Under those terms, API data is not used to train their models, and they may keep it for a limited period for abuse and safety monitoring.
What our server keeps. We don't store the frames or the request after the response has been produced. We do keep:
If iCloud is enabled for the App, your profile (name, discipline, injury note) and any older video reports sync through Apple's CloudKit to your private iCloud account. This lets them appear on your other devices. We can't access your private iCloud data. Your coaching journal and video clips do not sync through iCloud, but they may be included in your normal device backups.
We don't use any of this for advertising, and we don't track you across other companies' apps or websites.
Sometimes the coach shows you a demonstration of a movement or drill. These are public YouTube videos published by other people, such as CrossFit. They're credited in the App with their title and channel as published on YouTube. The App plays them through YouTube's own embedded player, using YouTube's privacy-enhanced mode (youtube-nocookie.com). We don't download, copy or alter them.
For this, YouTube acts independently under the Google Privacy Policy and the YouTube Terms of Service.
The App asks for camera access to record clips, and uses the photo picker to open videos you choose. Motion data is read only while you're recording. You can change camera and photo permissions at any time in iOS Settings.
Under UK and EU data protection law, we rely on:
| Purpose | Lawful basis |
|---|---|
| Providing coaching, saving your journal, generating share captions | Performing our contract with you (these Terms of Use) |
| Using an injury or pain note you give us to coach you safely | Your explicit consent. Health data is a special category of personal data. You can withdraw consent at any time by removing the note in Settings. |
| Showing demonstration videos from YouTube | Performing our contract with you |
| Purchases, memberships, top-ups and usage limits | Performing our contract with you |
| Preventing fraud and abuse of the free session; security | Our legitimate interests in protecting the service and keeping it affordable |
| Crash reports, analytics, server logs and improving the App | Our legitimate interests in running a reliable, improving service |
| Sending usage information to Apple for refund requests | Your consent (the Settings switch) |
| Keeping records we're required to keep; responding to legal claims | Legal obligation; legitimate interests |
Automated coaching. Coaching is produced automatically by AI. It's guidance about exercise technique and doesn't make decisions about you that have legal or similarly significant effects.
We share personal data only with service providers that process it on our behalf, under contracts that restrict how they use it:
When a demonstration video is shown, your device connects directly to YouTube (Google), which acts under its own privacy policy (see 2.7). We don't send YouTube any of your coaching data.
We may also disclose information if the law requires it, to protect our rights or someone's safety, or as part of a sale or transfer of the App. In the case of a sale or transfer, the new owner would be bound by this policy. We do not sell your personal information or share it for cross-context behavioural advertising.
Our service providers may process data outside the UK, including in the United States. Where they do, we rely on appropriate safeguards, such as UK adequacy regulations (including the UK Extension to the EU–US Data Privacy Framework where a provider is certified), or the UK International Data Transfer Agreement or Addendum to the EU Standard Contractual Clauses.
| Data | Kept |
|---|---|
| Videos, coaching journal, profile (on your device) | Until you delete them in the App or delete the App. iCloud copies remain until you delete them in iCloud settings. |
| Frames and requests sent for coaching | Not stored by us once the response has been produced |
| Coaching responses on our server | 7 days |
| Feedback submissions | 90 days |
| App Attest key records | About 400 days |
| Purchase, top-up and usage records | While you use the App, then as long as reasonably needed to handle refunds, disputes and abuse, or until you ask us to delete them where we're able to |
| Server logs | A short period, under our hosting provider's standard log retention |
| Crash and analytics data | Under Google Firebase's retention settings (analytics data up to 14 months) |
Depending on where you live, you may have the right to:
To make a request, email support@callustraining.com. Our server doesn't know your name or email, so please include details that help us find your records, such as the approximate date of a purchase. Much of your data exists only on your device, where you control it directly. We'll respond within one month.
If you're unhappy with how we've handled your data, you can complain to the UK Information Commissioner's Office at ico.org.uk. If you live in the EEA, you can complain to your local data protection authority. We'd appreciate the chance to put things right first.
US residents: we don't sell or "share" personal information as defined by US state privacy laws, and we don't use sensitive information to infer characteristics about you. You may request access to or deletion of your information as described above. We won't treat you differently for doing so.
Data in transit is encrypted. On your device, the coaching journal is stored with iOS file protection. Requests to our server must be authenticated, either as a verified App Store purchase or as a genuine copy of the App. No system is perfectly secure, but we work to protect your information and limit what leaves your device.
The App isn't designed for or directed at children. Users must be at least 16, and under-18s should use it only with a parent's or guardian's involvement (see our Terms of Use). If you believe a child has given us personal data without appropriate consent, contact us and we'll delete it.
We'll update this policy when the App or how we use data changes, and revise the date at the top. If a change is significant, we'll let you know in the App before it takes effect.
Leon Johnstone, Flat 7, Danescroft, Brent Street, London NW4 2QH, United Kingdom
support@callustraining.com