Privacy policy

Controller

Jens Niehues Möllenkamp 16, 48703 Stadtlohn, Germany Email: kontakt@tennisbuddy.site

What data we process

Account data: your email address and password (stored as a hash, managed via Supabase Auth).

Onboarding profile data: your playing level, training goals, available equipment, and weekly time budget.

Usage data: which videos you've watched and completed, saved videos and trainings (your list), your training history and weekly streak.

Technical data: IP address and timestamps, as they naturally occur when operating a website at the hosting provider.

Legal bases

Account, profile, training progress, and all features required to use the app: Art. 6(1)(b) GDPR (performance of the usage agreement).

Technically necessary processing such as server logs: Art. 6(1)(f) GDPR (legitimate interest in secure, functioning operation).

Embedded YouTube videos: Art. 6(1)(f) GDPR (legitimate interest in displaying the curated content) – see the section below.

Audience measurement: Art. 6(1)(f) GDPR (legitimate interest in understanding how the site is used) – see the section below. No consent-based advertising processing takes place: TennisBuddy does not use third-party marketing or tracking cookies and shows no advertising.

Hosting and processors

Supabase (database, sign-in, file storage) – data center in the EU (Frankfurt, Germany).

Vercel Inc. – hosting of the application itself.

Brevo (Sendinblue SAS, France) – sending system emails (registration confirmation, password reset).

Umami (Umami Software Inc.) – audience measurement, EU region (Germany). See the section below.

Data processing agreements under Art. 28 GDPR are in place with all providers listed above.

Cookies

One cookie for signing in (session), without which login is not possible.

One cookie for your chosen language (German/English).

Both are strictly necessary under § 25(2) TTDSG and do not require consent. TennisBuddy does not use marketing or tracking cookies.

Audience measurement

To understand how many people visit TennisBuddy, where they come from, and how long they stay, we use Umami – a privacy-friendly analytics tool hosted in the EU (Germany).

Umami does not set cookies, does not permanently store IP addresses, and does not build a profile of individual visitors: only aggregated numbers are evaluated (e.g. "340 visits this week"), and no individual person can be identified from them. That's why no consent is required.

Embedded videos

Training videos are embedded via the more privacy-friendly domain youtube-nocookie.com. Opening a video page automatically establishes a connection to Google's servers, which transmits your IP address among other data – regardless of whether you actually start playback.

More information: Google's privacy policy (policies.google.com/privacy).

Depending on the source, some content may also link to TikTok, Instagram, or Facebook.

Retention

We store account and profile data for as long as your account exists. Deleting your account (available anytime in account settings) removes the associated data.

Technical log data at the hosting provider is deleted according to their standard retention periods; see Vercel's privacy policy for details.

Your rights

You have the right to access (Art. 15 GDPR), rectification (Art. 16), erasure (Art. 17), restriction of processing (Art. 18), data portability (Art. 20), and objection (Art. 21).

You also have the right to lodge a complaint with a data protection supervisory authority – the competent authority for Stadtlohn (North Rhine-Westphalia) is the Landesbeauftragte für Datenschutz und Informationsfreiheit Nordrhein-Westfalen (LDI NRW).

Privacy contact

kontakt@tennisbuddy.site