Privacy Policy

Last updated: 21 October 2026

This Privacy Policy explains how Muld ("we", "us", "our") collects, uses, and protects personal data when you use the Muld mobile app ("the app"). The same policy applies wherever Muld is available. The way the app handles your personal data — account, location, finds, crash diagnostics — is the same in every country. What differs by country is the public map data shown on the map (section 2.4) and the national find register you can optionally report to (section 2.5). Country-specific points are marked Denmark or England below.

1. Data controller

Muld is an independent app operated from Denmark. For any privacy inquiry — including to identify the data controller or exercise your rights — contact hello@muld.dev, wherever you are based.

2. What data we collect

We collect only what is necessary to operate the app.

2.1 Account data

• Email address — to create and sign you in to your account.
• Authentication tokens — managed by Supabase Auth (our auth processor) to keep you signed in.
• Subscription status — managed by RevenueCat to track whether you have a Muld+ subscription.

2.2 Location data

• Precise GPS location — used in two ways:
  1. In-app while you have the app open — to centre the map on your position and to attach coordinates to finds you log.
  2. In the background, only while a detecting session is active — to record the path you walked. Background tracking stops the moment you end the session. We never run background location outside an active session.
• Location is stored on your device only (in the local SQLite database). It leaves your device only when you choose to send it out yourself — by submitting a find to a national register where in-app submission is offered (see 2.5) or exporting a file — and is never uploaded to our servers.

2.3 Find data

Each find you log stores:

• Coordinates (GPS)
• Date and time
• Photos you attach
• Notes, depth, category, and other fields you fill in

This data — including the photos you attach — is stored locally on your device in SQLite. It is not uploaded to our servers. A find leaves your device only when you choose to send it out yourself — by submitting it to a national register where in-app submission is offered (see 2.5) or exporting it as a file you share.

2.4 Map and protected-area data (by country)

The app displays base maps, terrain and protected / heritage areas drawn from public data sources. Map tiles are fetched from these services (directly or through our own caching proxy) as you pan and zoom. No personal data, account identifier or GPS position is sent to these map services — a tile request carries only the map area you are looking at, not who you are.

Denmark. Protected archaeological zones (fortidsminder, kulturarvsarealer, beskyttede sten- og jorddiger) from SLKS (Slots- og Kulturstyrelsen), the §3 nature register from Miljøportalen, and base/terrain/historical map data from Datafordeler and Dataforsyningen.

England. An OpenStreetMap base map, bare-earth LiDAR from the Environment Agency, historic Ordnance Survey maps, and the scheduled monuments and other protected sites from Historic England's National Heritage List for England. These overlays are shown for information; they may be incomplete or out of date and are not a legal authority.

2.5 National find registers (optional, by country)

England. There is no in-app find submission in England. Muld does not transmit your finds to the Portable Antiquities Scheme (PAS), to a Finds Liaison Officer, to a coroner, or to any other UK body. Recording a find with the PAS, and reporting possible treasure under the Treasure Act 1996, is something you do yourself — for example at finds.org.uk. Muld keeps your find record on your own device so you have it ready when you choose to do so.

Denmark. If you choose to submit a find to DIME (the Danish national metal-detecting register), the find data — coordinates, photos, description, finder identity — is sent to DIME's servers under their terms. This is opt-in per find; we do not submit automatically.

DIME is a non-commercial portal owned by Aarhus University (the data controller) and operated together with Moesgård Museum. By accepting DIME's terms during account creation, you agree to the following — these are DIME's terms, not ours, but you should know them before submitting:

• Find locations are shared with the responsible local museum at the time of submission. Sharing can exceptionally be postponed, but after 3 days the museum can access the exact find site if needed.
• Find images and descriptions are published on DIME under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 (CC BY-NC-SA 4.0) licence. GPS coordinates and personal data are NOT public — only approved museum staff, researchers with special access, and system administrators can see them.
• You can exceptionally hide a find from the public view for up to 6 months.
• If you delete your DIME account, your find data is anonymised — not deleted.

See metaldetektorfund.dk for DIME's full terms and privacy policy.

2.6 What we do NOT collect

• No advertising identifiers
• No advertising or product-analytics SDKs in the app (no Google Analytics, Firebase, Mixpanel, etc.). We use crash diagnostics only — see 2.8. The website's cookieless analytics is described in 2.7.
• No third-party SDK trackers
• No contacts, calendar, or other personal data outside what's listed above

2.7 Website analytics (muld.dev)

The muld.dev website uses Cloudflare Web Analytics to count page views and measure performance. It is cookieless, stores nothing on your device, and does not track you across sites or build a profile of you; we do not receive or store your IP address. This is the only analytics anywhere in Muld — the app itself contains no analytics SDK (see 2.6).

We previously ran a "notify me at launch" email list on this website. It has been retired: the sign-up form has been removed and the endpoint that received it has been closed, so we no longer collect any email address for a waitlist. If you had signed up and want your address removed, email hello@muld.dev.

2.8 Crash and error diagnostics (Sentry)

To keep the app stable, we use Sentry to collect crash and error reports. When the app crashes, Sentry receives the error and technical state (device model, OS version, app version, and a random anonymous install identifier). Your precise GPS location, find locations, notes, and photos are removed from crash reports before they leave your device.

Because a crash report is sent over the internet, Sentry derives an approximate, city-level location from your IP address (your region or city — not your GPS position or find sites). This coarse IP-based inference is standard for any internet service, is used only to diagnose crashes, and is never linked to your finds or movements. Crash data is processed in Sentry's EU data region.

3. Why we collect this data (legal basis under GDPR)

4. Who we share data with (sub-processors)

• Supabase (EU region) — account authentication. See Supabase's privacy policy.
• Cloudflare — hosts the muld.dev website and the app's map-tile proxy, and provides the site's cookieless Web Analytics (no cookies, no cross-site tracking, IP address not stored). See Cloudflare's privacy policy.
• RevenueCat — subscription management. See RevenueCat's privacy policy.
• DIME / Moesgaard Museum — only when you explicitly submit a find. Their privacy policy applies to submitted data.
• Sentry (crash diagnostics, EU data region) — receives crash reports if the app crashes. Sentry Inc. is US-based; data is stored in the EU and any US access is covered by SCCs. See Sentry's privacy policy.

We do not share your data with advertisers or data brokers, and we do not sell your data. The only analytics anywhere in Muld is Cloudflare's cookieless website analytics (section 2.7).

5. International transfers

Supabase data is stored in EU regions, and Sentry crash data is stored in Sentry's EU region. RevenueCat — and any US access to Sentry data by Sentry Inc. — may process data in the US under Standard Contractual Clauses (SCCs) approved by the European Commission.

6. Retention

• Account data — kept while your account is active. Deleted on request (see Your Rights below) or 12 months after sustained inactivity.
• Find data and photos on your device — kept until you delete the find or uninstall the app.
• Subscription records — retained for as long as legally required (accounting, tax — typically 5 years in Denmark).
• DIME submissions — once submitted, data is held under DIME's terms, not ours.
• Crash diagnostics — crash reports are retained only as long as needed to diagnose stability issues, then removed on Sentry's rolling retention schedule.
• Website analytics — Cloudflare keeps only aggregate page metrics; there is no per-visitor record to retain or delete.

7. Your rights (GDPR / UK GDPR)

If you are in the EU/EEA your rights arise under the GDPR; if you are in the United Kingdom the equivalent rights arise under the UK GDPR and the Data Protection Act 2018. In both cases you have the right to:

• Access your data — request a copy.
• Rectify inaccurate data.
• Erase your data ("right to be forgotten"). Erasing your account removes your authentication data on our servers. Your finds, photos and tracks live only on your device — delete them in-app or by uninstalling.
• Restrict processing of your data.
• Object to processing.
• Data portability — receive your data in a machine-readable format.
• Withdraw consent at any time for background tracking and DIME submissions (the data already shared with DIME is governed by DIME's policy).
• Lodge a complaint with your data-protection authority — in Denmark/the EU, the Danish Data Protection Authority (Datatilsynet, datatilsynet.dk); in the UK, the Information Commissioner's Office (ICO, ico.org.uk).

To exercise any of these rights, email hello@muld.dev. We respond within 30 days.

8. Security

• All network traffic uses HTTPS / TLS.
• Auth tokens stored in the device's secure storage.
• Supabase encrypts data at rest.
• We do not store passwords ourselves; Supabase Auth manages hashing.

9. Children

The app is not intended for users under 13. We do not knowingly collect data from children. If you believe a child has used the app, contact us and we will delete the data.

10. Changes to this policy

We may update this policy. The "Last updated" date at the top reflects the most recent change. Material changes will be announced in-app on the next launch after the change.

11. Contact

hello@muld.dev