About Nextbox
I built Nextbox because my inbox had stopped being a place where I talked to people and become a place where things accumulated. The conversations that actually mattered were three screens down, under a pile of receipts.
So Nextbox does one structural thing: it notices when a thread is a real back-and-forth — when at least two actual humans have written in it — and puts those somewhere I'll see them. Everything else stays exactly where it was, in a complete list, in the order it arrived.
The AI is on-device and optional, and it can't send anything. That isn't a feature I'm bolting on; it's the only way I'd be willing to point a language model at my own email.
Frequently asked
Does my email go to your servers?
No. Nextbox connects from your device straight to your mail provider over an encrypted connection. Message content, attachments, contacts, and search queries never touch a Nextbox server — there is no mail server to touch. Licensing and support (Note to Joe) are the only things that talk to me, and they never see your mail.
How does the AI work if my mail stays on my device?
It uses the language model built into your phone's operating system. The model runs locally, has no network access, and has no ability to send, delete, archive, or read anything you haven't opened. It's available only on newer devices and in some languages — Nextbox tells you plainly when your device can't do it, and everything else in the app works normally either way.
Can the AI send an email on my behalf?
No, and it structurally cannot. Suggested replies drop into the normal composer as editable text. You review it and you press send. There is no auto-send, no auto-archive, and no autonomous agent.
If Nextbox decides something isn't a priority, does it disappear?
Never. Priority is a label on a card, not a mailbox. The Feed's complete, newest-first list of everything is always one tap away, and Nextbox can't hide mail from it even if the suggestion is wrong. When it is wrong, you correct it, and it learns — on your device only.
Which email providers work?
Gmail and Outlook sign in with OAuth. Fastmail, iCloud, and self-hosted accounts work over standard IMAP with an app password. Actions you take in Nextbox — archive, star, read — show up correctly in your provider's own app, and vice versa.
Is there a desktop version?
Yes — macOS, Windows, and Linux, sharing the same on-device architecture. Desktop doesn't have an OS-level private language model yet, so the AI features are phone-only for now. Nextbox says so rather than quietly sending your mail somewhere to make up the difference.