Last updated: August 2026

Privacy Policy

Filament is a filament inventory tracker for 3D printing. Your spool data lives on your device and, through Google's own backup services, in your own Google Drive. We do not run servers that store your spools, your prints, or anything else about you.

1. Who we are

Filament is developed and maintained by Bruno Santos, trading as The Cynic Dev ("we", "us", "our"). For questions about this policy, email us at the address at the bottom of this page.

2. What data Filament stores

Filament stores the following data on your device, in the app's local database:

• Spool details you enter — name, brand, material, colour, diameter, weight remaining
• Print history you log against each spool — job name, grams used, date, notes
• Drying log entries (Pro) — temperature and duration per session
• Photos you attach to a spool (Pro) — picked via Android's built-in photo picker
• App settings — weight unit, currency symbol, notification frequency, theme

None of this data is sent to us. It leaves your device only through Google's own services, in the two ways described in sections 4 and 5 — both of which put it in storage that belongs to you, not to us.

3. What data we do NOT collect

• We do not collect analytics or usage telemetry
• We do not use crash reporting or third-party tracking SDKs
• We do not run any server that receives or stores your spool data
• We do not sell or share your data with any third party
• We show no ads and use no ad networks

4. Android Auto Backup (all users)

Filament uses Android Auto Backup, the backup service built into Android. When your phone is idle, charging and on Wi-Fi, Android copies the app's data to your own Google Drive so that reinstalling Filament, or setting up a new phone, restores your inventory instead of starting empty. This applies to all users, including free ones, and it is separate from the Pro Cloud Backup feature described below.

• The copy is stored in your own Google Drive, under your Google account. It does not count against your visible Drive storage quota and does not appear in your Drive file list
• The transfer is performed by Android itself. We do not operate it, cannot trigger it, and cannot read the result
• What is copied: your spool database (spools, print history, drying log, activity log), attached photos, and your app settings
• What is deliberately excluded: your Pro purchase record (Google Play is the authority on that and re-checks it directly) and Cloud Backup's internal sync bookkeeping
• You can turn this off. On most devices: Settings → Google → Backup, or Settings → System → Backup. Turning it off stops future backups and, on some Android versions, deletes existing ones
• Google's handling of this data is governed by the Google Privacy Policy

5. Cloud Backup and Google Drive (Pro feature)

Cloud Backup is optional and off by default. If you turn it on and sign in with your Google account, Filament requests exactly one Google Drive permission: drive.appdata — access to a single hidden folder ("app data folder") that Google creates specifically for Filament inside your own Drive storage.

• This folder counts against your own Drive storage quota, not ours
• It does not appear in your regular Drive file list and cannot be opened by any other app
• We — the developers — have no access to this folder or its contents. Nothing about it is visible to us at any point
• Your device talks directly to Google's servers to read and write this folder; no request passes through anything we operate

You can revoke this access at any time at myaccount.google.com/permissions. Revoking access or uninstalling Filament does not delete data already stored in the folder — sign back in with Cloud Backup enabled to resume, or contact Google to clear leftover app data for your account.

6. Photo attachments (Pro feature)

When you attach a photo to a spool, Filament opens Android's built-in Photo Picker — the system picker Google provides so apps never need broad access to your photo library. Filament only receives the single photo you choose. The photo is stored locally and, if Cloud Backup is on, also uploaded (compressed) to the same hidden Drive folder described above.

7. Payments and Google Play

Filament Pro is a one-time purchase made through Google Play Billing. Google acts as the merchant of record for this transaction: Google collects your payment details and processes the charge directly. We receive confirmation that a purchase was made but never see or store your payment card details.

Google's privacy policy governs how they handle your payment data: policies.google.com/privacy. Refund requests are handled by Google Play directly — see the Google Play refund policy.

8. Low-stock notifications

Filament can notify you when a spool is running low. This check runs entirely on your device on a schedule you control in Settings — it does not contact any server, and no data leaves your device to generate this notification.

9. Permissions we request and why

• Notifications — to show the low-stock alert described above
• Internet — used only for Cloud Backup (talking to Google Drive) and Google Play Billing (processing your purchase). Filament makes no other network requests

10. Data retention and deletion

Your data stays on your device until you delete it or uninstall the app. Deleting a spool moves it to a recycle bin for 30 days (so you can restore it from the History screen), after which it is permanently removed from your device and, if Cloud Backup is on, from your Drive folder on the next sync.

• Uninstalling Filament removes all locally stored data from your device
• An Android Auto Backup copy (see section 4) may remain in your Google Drive after uninstalling, so that reinstalling restores your data. You can delete it yourself from your device's backup settings, and Google deletes it automatically if the app goes unused for an extended period
• Revoking Drive access (see section 5) stops future syncing but does not retroactively delete what's already in your Drive folder

11. Children's privacy

Filament is not directed at children under 13. We do not knowingly collect personal information from children.

12. Changes to this policy

We may update this Privacy Policy as the app evolves. Material changes will be noted with an updated date at the top of this page and a new row in the change history above. Continued use of Filament after changes constitutes acceptance of the updated policy.

13. Contact

Questions about this policy? Email thecynicdev@gmail.com. We aim to respond within 48 hours.