About Zimmer
Zimmer Messenger is a notification-first messaging app for iPhone. It's organized around channels — broadcaster-led group chats that anyone can find, follow, and reply in — plus 1:1 direct messages between members. Every message you send, in any channel or DM, is end-to-end encrypted on your device before it ever reaches our servers.
Channels can be public (joinable by code or shared link) or private (joinable with a password). Broadcasters control who can post, what members see, and whether private DMs are open. Members get the right notifications and ignore the rest — mute a channel, turn it off entirely, or block a sender, all in one tap.
Zimmer is built on Apple's native iOS frameworks and Google Firebase. Our goal is simple: the messaging app that respects your attention and your privacy.
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End-to-end encryption on every message
Text in DMs, public channels, and private channels is encrypted with X25519 key agreement and AES-256-GCM. Only the people in your conversation can read it — not us, not Google, not OneSignal.
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Instant opens with a local cache
Messages you've seen are cached on your phone, so reopening a chat is instant. Scroll up to load older history one page at a time, iMessage-style. Clear the cache from Settings whenever you want.
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Channels built for broadcasters
Create a public or private channel in seconds. Decide who can post, whether replies go to you or the whole channel, and how members appear. Share it with a QR code, a code, or a universal link that opens straight into Zimmer.
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You control what shows up
Mute or turn off any channel. Block or decline DM requests. Clear local history at any time. Push notifications use a generic "New encrypted message" body so the content of E2EE messages never leaves your device.
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Native iOS, no ads, no tracking
Zimmer is a pure SwiftUI app for iPhone. We don't sell your data, we don't show advertising, and we don't track you across other apps or websites.