mast privacy policy
Last updated 26 August 2026
This policy covers the Mast app for iPhone and Apple Watch, made by Tissue Systems ("we"). Mast has no accounts, no analytics, and no advertising, so this document is short. The platform that Mast's servers run on has its own privacy policy; this one describes what the app itself stores and why.
01 What Mast stores
- A device record. When you allow notifications, the app registers with our servers and we store a random device identifier, the push token Apple issues for delivering notifications to your phone, and the device name iOS reports (for telling your devices apart if you link more than one). There is no email address, no password, and no profile.
- Your channels. The name, kind, priority, and schedule of each channel you create, and the key that forms its send address.
- Your messages. The content posted to your channel addresses, with its priority and timestamps, and any acknowledgements. Messages are kept for 30 days and then deleted.
- Escalation links. If you pair with another Mast user for escalation, we store the link between the two device records — that is what routing an unanswered page to them requires.
02 What Mast never collects
No analytics or crash-tracking SDKs, no advertising identifiers, no location, no contacts, no cross-app tracking of any kind. We do not sell any of the data above, and we do not use your message content to train machine-learning models.
03 Where messages travel
A message posted to your channel address travels to our servers over HTTPS and is delivered to your phone through the Apple Push Notification service, which is how any iOS notification arrives. Apple processes the notification payload to deliver it; Apple's handling is described in its own privacy documentation. Message content is otherwise stored only on infrastructure we operate — see the platform security page for where and how.
04 The channel address is a key
Anyone who has a channel's send address can post to that channel. That is the design — it is what lets a shell script page you with one line — so treat the address like a password. You can rotate a channel's key in the app at any time; the old address stops working after a short grace period.
05 Purchases
The one-time purchase is processed entirely by Apple through the App Store. We receive a receipt that marks your copy as purchased; we never see your payment details.
06 Connecting a Tissue account
Connecting a Tissue account is optional and nothing in Mast requires it. If you connect one, we store the link between your device and that account, and the account's data is covered by the platform privacy policy. Disconnecting in the app forgets the account credential on the device; to remove the stored link as well, email privacy@tissue.systems.
07 Deleting your data
Deleting a channel in the app removes it and stops its address. Messages delete themselves after 30 days. Unlinking a device removes its record from our servers, and deleting the app from your phone invalidates its push token, after which nothing further can be delivered or stored. For anything beyond that — including removing every trace of a device immediately — email privacy@tissue.systems from any address, naming the channel or device, and we will delete it.
08 Changes and contact
Material changes to this policy move the date at the top. Questions about privacy reach privacy@tissue.systems; anything else about Mast reaches support@tissue.systems.