Epistles Mail vs Mailbutler Smart Assistant

Epistles Mail is an email app with a unified inbox, offline access, scheduled sending, and calendar tools. It works with Gmail, Microsoft 365, Fastmail, JMAP servers, iCloud, Proton, and IMAP. Mail content, attachments, drafts, and the search index stay on the device, and search runs against a local cache. Its local-first, zero-knowledge encryption model stores ciphertext in Cloud Vault; Epistles servers do not store mailbox content. The app is available on Android, iOS, macOS, Windows, Linux, and the web, as well as Apple Watch and Wear OS. The free plan supports up to two connected accounts. Pro costs $35 per year after a 14-day free trial and allows unlimited connected accounts, with password-protected, expiring email included. Pro uses one flat price rather than per-seat billing. iCloud support includes mail, calendar, and contacts. The watch app supports archive, snooze, pin, template replies, and RSVP. Epistles passed a CASA Tier 2 security assessment by TAC Security.

Mailbutler Smart Assistant adds AI writing and email-management tools to Apple Mail, Microsoft Outlook, and Gmail. It drafts messages from keywords or prepares replies using details a user supplies, with controls for format, length, style, tone, and language. It can summarize selected emails, identify to-dos for Mailbutler Tasks, and suggest spelling and grammar improvements to drafts. Mailbutler says the assistant uses OpenAI GPT-4o. Smart Assistant is included in a 14-day trial, then requires a Smart or Business subscription. The separate free Starter plan includes a visible Mailbutler watermark on sent emails. Mailbutler says email subjects and bodies are processed by Microsoft Azure OpenAI Service in the EU, with personal data redacted before submission to the underlying model. It also says backend data is encrypted and that it is ISO/IEC 27001 certified and GDPR compliant. Apple Mail support is listed for macOS Tahoe, Sequoia, Sonoma, and Ventura; mobile apps require iOS 15 or later or Android 7 or later.