Canary Mail

Canary Mail is an AI-assisted mail client that also takes encryption seriously: end-to-end encrypted mail between Canary users, a pin lock on the app itself, send later, read receipts, and an assistant that drafts replies and compresses long threads into something you can act on. One single-user licence covers macOS, iOS, Windows and Android across up to five devices, which is rare at this price in this category.

The reason it is listed here is that both paid tiers are sold as either a year at a time or once and for all, and Canary's own help pages say a lifetime licence includes future updates for the plan you bought. Where you buy matters more than usual, though. The website now prints its lifetime prices — $100 for Growth, $300 for Pro+ — while the Mac App Store lists both its lifetime bundles at $99.99. Apple's tier names do not line up with the website's, so the cheaper store bundle may be the $100 tier or it may be the $300 one, and nothing published resolves it. Ask support which tier a store purchase grants before spending the money; the difference is $200.

Be clear-eyed about the risk. A product carrying per-user model costs is the least likely candidate for terms that hold for a decade, and one-time AI pricing tends to grow caps over time. If you want mail software that cannot change its mind, a plain IMAP client is the safer purchase.