Kerna vs MailMaestro

Kerna is an AI email assistant for Gmail and Outlook on macOS, Windows, and the web. At a user’s request, it sorts open messages into categories such as Urgent, Respond, Invoice, Waiting, and Notification; users can also set custom categories and industry taxonomies. It drafts replies based on the full thread, with controls for intent and tone, and makes structured thread summaries for conversations of up to 50 messages. It can summarize attachments, extract selected fields into exportable tables, and translate inbound messages and outbound replies in 45 languages. Integrations include Calendar, Contacts, and Sheets as well as Gmail and Outlook. Kerna says it acts only when a user initiates a request, processes content in memory, discards it afterward, and redacts personal data before it reaches the inference provider. Its trust information reports TLS 1.2 or higher in transit and AES-256 encryption at rest. Kerna has a free plan; paid plans start at €12/mo. Outlook requires a Microsoft-hosted mailbox; POP or IMAP and on-premises Exchange are unsupported.

MailMaestro is an AI email assistant for drafting, revising, and organizing professional email. It writes messages from scratch, polishes drafts, fixes typos, and summarizes email threads and attachments; those summaries can inform generated responses. Rapid Replies offers contextual response options that users can turn into a professional reply, and the assistant can create professional responses in 18 languages. It detects meeting invitations, checks availability in Microsoft Outlook or Gmail calendars, and enables one-click responses. Users can share thread summaries in Microsoft Teams channels or direct messages. Magic templates and keyword shortcuts help with repetitive messages and commonly inserted details. MailMaestro is available as an extension and on the web. Its Gmail version is a Chrome extension and works only in Google Chrome; its Outlook version works with Outlook web, legacy Outlook, and new Outlook. The free plan limits Compose, Reply, and Improve to three uses per week. The Professional/Team plan is $15 a month per seat, and MaestroDuo is $27 a month per seat. Maestro Labs says customer data is not used to train AI models and is encrypted at rest and in transit.