Privacy Policy

Last updated: 26 August 2026

Underline is a game about building metro networks in real cities. This document describes what data the app does — and does not — collect.

Short version

• Underline collects nothing. No accounts, no sign-in, no analytics, no crash reporting, no advertising, and no tracking across other apps.
• It works entirely offline. Every city's map is bundled inside the app, so it does not need a connection to play and does not send your play anywhere.
• Your saved games and settings are stored only on your device.
• The one-off purchase is handled by Apple's App Store. Underline never sees your payment details.

What stays on your device

The following are stored locally on your device only, using the operating system's standard app storage. They never leave your device:

• Your saved games — the lines and stations you've built, your balance, and each city's history
• Which commissions you've completed and which achievements you've earned
• Your settings, such as the theme and which map overlays you prefer

If you delete the app, this data is removed with it.

What is sent over the network

Nothing about you, and nothing about your play. Underline has no server of its own, no account system and no analytics, so there is no place for your data to be sent even in principle.

The maps are not streamed. Every city ships inside the app as a pre-built offline map, which is the main reason the download is large — and the reason the game keeps working with no signal.

Purchases

Underline offers one non-consumable in-app purchase, which unlocks the remaining cities, their commissions and unlimited-money mode. The transaction is handled entirely by Apple through the App Store. Underline receives only a confirmation from the operating system that the purchase is owned by the Apple Account signed in on the device; it never sees your name, your payment details or your Apple Account.

Third-party services

None. Underline includes no analytics SDK, no crash-reporting service, no advertising SDK and no other third-party tracking.

The map data bundled in the app is derived from OpenStreetMap (© OpenStreetMap contributors, Open Database Licence), together with population and employment grids from the European Commission's Global Human Settlement Layer and, for the UK, Office for National Statistics data under the Open Government Licence. These are data files compiled into the app ahead of time, not services the app contacts while you play.

Children

Underline is rated 4+ and does not knowingly target or collect data from children under 13. Since the app collects no data from anyone, it collects none from children either.

Permissions

Underline does not request any of the following: your location, contacts, photos, camera, microphone, App Tracking Transparency, notifications, or background activity.

Changes to this policy

If this policy changes in the future, the updated version will be published at the same URL where you are currently reading it, and the "Last updated" date above will change.

Contact

If you have questions about this policy, email harryattenborough@gmail.com.