Dusk keeps your Mac and iPhone in step within seconds. What syncs, what never does, and the security behind it: encryption, passwordless sign-in, per-account isolation and one-tap deletion.
Dusk's iPhone app arrives after the Mac launch, and when it does, your work follows you. Start a reply on your Mac, pick up your phone, and it's there, usually within a few seconds, with no pull to refresh. Here's exactly what syncs, what never does, and how it's protected.
Why sync at all
Email doesn't happen in one place. You triage on the Mac in the morning, reply from your phone on the train, and finish a long message back at your desk. Without sync, each device starts from scratch: sorting again, summarising again, and losing the reply you'd half written.
With sync, the work is done once and shows up everywhere:
- Replies in progress move with you between Mac and iPhone.
- Sorting and summaries made on one device are ready on the other.
- Suggested replies and your writing style are the same on both.
What syncs, and what never does
| Syncs through Dusk's server | Never goes through Dusk |
|---|
| Drafts and replies in progress | Your emails and attachments |
| Suggested replies Dusk wrote for you | Your Gmail and iCloud sign-ins |
| Which split each email is in, and its one-line summary | Your contacts |
| Your writing style (greeting, sign-off, length) | Your licence |
Your emails are downloaded straight from Google or iCloud to each device, exactly as before. The AI still runs on each device, using Apple's on-device model. What syncs is the small amount of work Dusk does on top of your mail.
How it's protected
Encrypted in transit and at rest
Everything travels over encrypted connections, and it's encrypted where it's stored.
Only you can reach your data
Every request to the server is checked against the account making it. An account can only ever read or change its own records.
No password to steal
Dusk accounts don't have passwords. You sign in with a 6-digit code sent to your email, which expires after 10 minutes and allows 5 tries. Once you're in, your session renews every hour with a key that changes each time, and the old one stops working. The long-lived key is stored hashed on our side and in the Keychain on your device.
Nothing searchable
Each record is named with a one-way hash, and what's inside is never indexed or written to logs.
Yours to delete
Delete account in Settings removes everything synced from our server. Your mail and everything on your devices stay as they are.
Optional
Sync only starts when you sign in to a Dusk account. Without one, nothing is synced and Dusk never contacts its server. On the Mac it's off until you turn it on.
Why not iCloud?
We tried. iCloud keeps app data per Apple Account and doesn't sync live, so a reply typed on the Mac wasn't reliably there when you picked up the phone, and it could never arrive if the two devices used different Apple Accounts. A Dusk account works whatever Apple Account each device uses, and updates arrive while you watch.
The short version
Your emails come straight from Google or iCloud. The AI runs on your devices. Sync carries only drafts, sorting, summaries and your style, encrypted, reachable only by you, and deleted when you say so. Read more about how Dusk's AI works.
Questions
- Does Dusk sync my emails?
- No. Each device downloads your emails directly from Google or iCloud. Sync carries drafts, replies in progress, sorting, summaries and your writing style.
- Is Dusk sync encrypted?
- Yes, in transit and at rest.
- Do I need an account to use Dusk?
- No. An account is only needed for sync between devices. Without one, nothing is synced and Dusk never contacts its server.
- How do I delete my synced data?
- Choose Delete account in Dusk's settings. It removes everything synced from Dusk's server, and leaves your mail and devices as they are.
- How fast is Dusk sync?
- With both apps open, a change on one device usually appears on the other within a few seconds.
Fast, private email for $49 once
Pre-orders are open at the launch price. One payment covers the Mac app and the AI, and the iPhone app when it arrives.
Pre-order Dusk