Who we are
GolfStack is operated as a sole-founder product by the team behind stack.golf and app.stack.golf. We are responsible for processing personal data you provide when using the GolfStack mobile app, web app, and marketing website. For any privacy question, reach us at hello@stack.golf.
What we collect
Account data. Email address, password (hashed via Supabase Auth), display name, and optional handicap index, home course, and country.
Round data. Score and putts per hole, fairway hit, course played, tee selection, date and time. If you grant permission, the device GPS at the time of a round is captured to pin the course location.
Mental game responses. Your answers to per-hole mental-game prompts (Commitment, Routine, Reset, Aim, Steadiness) and any pre-round intentions or post-round reflections you write.
Photos. If you use Scorecard Scanner, the image of the paper scorecard is sent to our AI vision provider for OCR. We do not store the original image after extraction unless you save the round.
Device and usage data. Device type, operating system version, app version, crash reports, and basic analytics events (round logged, share card generated, AI coaching story viewed). We do not use third-party advertising trackers.
Payment data. If you subscribe to Pro or Tournament, payment is handled by our payment processor (Stripe). GolfStack does not see or store your card number — we only store the subscription status, plan, and billing email.
How we use it
We use your data to operate the product: render your scorecards and stats, generate your AI coaching story, calculate the Consistency Score, build your Mental Game Profile over time, search the course database, share rounds at your request, send transactional emails (receipts, password resets, tournament invitations), and provide customer support.
We do not sell personal data. We do not show personalized advertising. We do not share your round data with other users unless you explicitly share it (share cards, tournaments).
AI processing
Your round data, mental game responses, and pre/post-round notes are sent to Anthropic Claude to generate your AI coaching story and personality description. Scorecard images are sent to Anthropic Claude Vision for OCR. Anthropic processes this data under their privacy policy and does not train models on customer API data by default.
If you would prefer not to have round data sent to an AI provider, you can disable AI coaching in account settings. You will still be able to log rounds and see your stats; only the coaching story and OCR are affected.
Third-party processors
We use the following processors to run the service. Each receives only the data necessary to perform its function.
- Supabase — database, authentication, file storage. Hosted in the United States.
- Anthropic — AI coaching story generation and scorecard OCR.
- Open-Meteo — weather data for course conditions.
- Vercel — website hosting and edge delivery.
- Stripe — payments and subscription billing (for paying subscribers only).
- Plausible — privacy-friendly analytics for the marketing website (no cookies, no personal data).
Retention
Round and account data are retained for as long as your account is active. If you delete your account, we delete your rounds, mental game profile, and AI coaching stories within 30 days. Billing records may be retained longer where required by tax law (typically 7 years). Crash logs and analytics events are aggregated and not tied to your identity beyond 90 days.
Your rights
Depending on where you live (EU, UK, California, India, and many other jurisdictions), you have the right to access, correct, export, or delete your personal data, and to withdraw consent. To exercise any of these rights, email hello@stack.golf with the subject "Data request." We will respond within 30 days.
You can also export your round history as a CSV at any time from account settings, and you can delete your account from the same screen.
Children
GolfStack is not directed to children under 13 (or under 16 in the EEA/UK). We do not knowingly collect personal data from children. If you believe a child has provided personal data to us, please contact hello@stack.golf and we will delete the data.
Security
We protect your data with industry-standard measures: encryption in transit (TLS 1.2+), encryption at rest via Supabase, row-level security on the database, hashed passwords, and limited internal access. No method of transmission or storage is 100% secure, but we work hard to keep your data safe.
Changes to this policy
If we materially change how we handle data, we will update this page and, where required, notify you in-app or by email at least 14 days before the change takes effect. The "Last updated" date at the top reflects the most recent revision.
Contact
For privacy questions or data requests, email hello@stack.golf. We will respond within 30 days.