← NextSplit

Privacy Policy

Last updated: April 2026

Who we are

NextSplit (“we”, “us”, “our”) is a training platform for runners and endurance athletes. We are the data controller for personal data collected through nextsplit.app and associated mobile applications.

Registered in England and Wales. ICO registration number: [UPDATE AFTER REGISTRATION].

Contact: privacy@nextsplit.com

What data we collect

Account data: Your name, email address and password (hashed — we never see it in plain text).
Profile data: Age, biological sex, injury notes, health flags, running experience, and training preferences you provide during onboarding.
Training data: Session logs, distances, paces, heart rate, gym exercises, wellness check-ins, and race results you log in the app.
Goal data: Race goals, target times, and training objectives you set.
Strava data: If you connect Strava, we import your recent activity history to pre-fill your profile. We store access tokens securely.
Usage data: Which features you use, how you navigate the app, and error logs. We use PostHog analytics and Sentry error monitoring.
Feedback: Messages you send via the in-app feedback widget.
Device data: Browser type, device type, and IP address for security and analytics purposes.

Why we collect it (legal basis)

Contract performance: We need your account and training data to provide the NextSplit service — personalised plans, AI coaching, progress tracking.

Legitimate interests: We use usage analytics to improve the product and error monitoring to fix bugs.

Consent: We ask for your consent before sending push notifications. You can withdraw consent at any time in Settings.

How we use your data

  • Generate and personalise your training plan
  • Provide AI coaching feedback based on your actual training data
  • Calculate your pace zones, ACWR, and progress metrics
  • Send push notifications you have opted into
  • Enable coach-athlete relationships (if you choose to connect with a coach)
  • Improve the product through aggregated, anonymised usage analytics
  • Respond to support requests and feedback

AI and your data

NextSplit uses the Anthropic Claude API to generate training plans and provide coaching feedback. Your training data, profile information and goals are sent to the Claude API to generate personalised responses.

Anthropic's data processing is governed by their own privacy policy. We do not use your data to train AI models.

Who we share data with

Supabase: Database and authentication (EU region). Privacy policy
Anthropic: AI coaching and plan generation. Privacy policy
Vercel: Hosting and edge network. Privacy policy
PostHog: Product analytics (EU-hosted). Privacy policy
Sentry: Error monitoring. Privacy policy
Strava: Activity import (only if you connect). Privacy policy
Stripe: Payment processing (if you subscribe). Privacy policy

We do not sell your data. We do not share your data with advertisers.

Coach data sharing

If you connect with a Professional Coach through NextSplit, the following data is shared with your coach when the relationship is active:

  • Training logs and session completion (on by default)
  • Wellness check-ins and readiness scores (on by default)
  • Nutrition diary (off by default — you opt in)
  • Body weight logs (off by default — you opt in)

You can revoke coach data access at any time in Settings → Coach Access.

Data retention

We keep your data for as long as your account is active. When you delete your account, all personal data is permanently deleted within 30 days, including training logs, wellness data, goals, and profile information.

Your rights (GDPR)

If you are in the UK or EU, you have the right to:

  • Access — download all your data from Settings → Export my data
  • Rectification — edit your profile and data in-app at any time
  • Erasure — delete your account from Settings → Delete account
  • Portability — export your data in JSON format from Settings
  • Withdraw consent — turn off notifications in Settings at any time
  • Object — contact us at privacy@nextsplit.com to object to any processing

To exercise any right not available in-app, email privacy@nextsplit.com. We will respond within 30 days.

Cookies and tracking

We use essential cookies for authentication (Supabase session cookies). We use PostHog for analytics, which sets a cookie to identify returning users for product improvement purposes. We do not use advertising cookies.

Security

All data is transmitted over HTTPS. Passwords are hashed using industry-standard bcrypt. Database access is protected by Row Level Security (RLS) — every user can only access their own data. We use Sentry to monitor and respond to security incidents.

Changes to this policy

We will notify you of significant changes via email or in-app notification. The “last updated” date at the top of this page reflects the most recent revision.

Contact

For privacy questions or to exercise your rights: privacy@nextsplit.com