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. The number, however, is not on the pricing page. The only place a lifetime price is printed before checkout is Apple's App Store listing, where the Growth and Pro Lifetime Bundles both read $99.99 — and because Apple's tier names do not match the website's Growth and Pro+, it is worth asking support what a store purchase actually grants before spending the money.

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.