Composer AI vs Kerna

Composer AI is an email drafting tool for Gmail that uses an email thread and the user’s tone to prepare replies. Users connect Gmail, open a message, review and edit the generated draft, then send it. The homepage states that replies are produced in under three seconds. Composer AI is available on the web and as a browser extension, using Google APIs to read Gmail threads during composition. Its Free Beta Tier costs nothing and includes 20 draft compositions per account; users may request a manual limit increase. The privacy policy says thread content and prompts are sent to OpenAI, retained for up to 30 days, and not used for model training. Full conversation and email content is logged to LangSmith for debugging and service improvement, with deletion after 14 days. The service is experimental beta software without service-level agreements or uptime guarantees and advises against highly sensitive communications.

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.