01What Skein collects
Skein collects nothing. There is no Skein Studio backend that receives your data, no analytics SDK in the app, no crash-reporting service, no advertising identifier, no telemetry. The app is a client for your Mattermost server, and that's the only network it talks to.
This is verifiable: Skein opens exactly one network connection at runtime — to the Mattermost server URL you entered on the sign-in screen — for REST and WebSocket traffic. If you'd like to confirm, you can run a packet inspector against the device while signed in.
02What stays on your device
Skein keeps a minimal amount of state locally so you don't have to sign in again every launch. Nothing here leaves the device unless you tell it to — none of it is uploaded to Skein Studio, ever.
- Server URL
- The URL you entered, e.g.
https://chat.example.com. Stored in AsyncStorage so the app remembers which server to talk to. - Session token
- The opaque session token your Mattermost server returned at sign-in. Stored in the iOS Keychain (or the Android EncryptedSharedPreferences) — encrypted at rest, scoped to Skein, removed on sign-out.
- Profile snapshot
- Your Mattermost username, display name, and email — the same fields any Mattermost client receives at login. Used to render your avatar and the Settings screen. Cleared on sign-out.
- Preferences
- Theme, density, accent, type pairing, thread metaphor strength. AsyncStorage. Local-only.
- In-memory caches
- User profiles and presence statuses for people you've messaged with, kept only while the app is running. Cleared on sign-out and on app close.
03What goes to your Mattermost server
Your messages, files, reactions, threads, channel memberships, and any other Mattermost activity all live on your Mattermost server. Skein reads and writes them via the official /api/v4 REST and WebSocket endpoints — exactly as the official Mattermost mobile client and any other compliant client would.
Whatever data-handling policies your server's administrator has configured continue to apply. Skein adds no logging, no audit trail, and no relay layer of its own.
04Permissions
Photos
When you tap the paperclip in the composer, iOS asks for permission to access your photo library. Skein only opens the picker when you tap; it does not scan your library, read EXIF metadata, or upload anything you didn't pick. The image you select is uploaded directly to your Mattermost server's /api/v4/files endpoint and attached to the post you send. If you remove the image before sending, the upload is discarded server-side.
Camera
Reserved for a future "take a photo to send" feature. Currently unused; the permission string is declared so iOS can present it without a separate update if and when we ship that flow.
Push notifications
When push is implemented, Skein will register an Apple Push Notification token directly with your Mattermost server. The server uses the token to send notifications to your device through Apple's infrastructure. Skein Studio is never in the path. (Push is not yet shipped at the time this policy was last updated.)
05Third-party services
The Skein app contains no third-party SDKs for analytics, advertising, attribution, or A/B testing. The only third parties involved are:
- Apple — distributes the app via the App Store and (eventually) routes push notifications via APNs.
- Google — distributes the Android build via Google Play and (eventually) routes push notifications via FCM.
- Your Mattermost server's hosting provider — wherever your server lives is where your data lives. Skein doesn't choose this for you.
The marketing website you're reading right now loads web fonts from Google Fonts; the rest of the page is served as static HTML. The website does not use cookies, analytics, or any tracking pixels.
06Children
Skein is a tool for adult workplace messaging. We don't market it to or knowingly serve users under 13. Because Skein collects nothing, there is also nothing it could collect from children — but we mention this for completeness.
07Changes to this policy
If the way Skein handles data ever changes, this page will be updated and the change noted in the app's release notes. Material changes — especially anything that would introduce data leaving your device or your server — will be flagged on the in-app Settings screen the next time you launch.
08Contact
Questions, audit requests, or compliance-team paperwork: privacy@skein.app. Skein is built by Skein Studio, an independent two-person studio with offices in Berlin and Tokyo. We are not affiliated with Mattermost, Inc.