Jetwriter AI vs Kerna
Jetwriter AI
jetwriter.aiKerna
kerna.ioSide by side
| Figure | Jetwriter AI | Kerna |
|---|---|---|
| Price from | $14/mo | €12/mo |
| Free plan | Yes | Yes |
| Free trial | Yes | — |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | — | Yes |
| macOS | — | Yes |
| Plans published | 5 | 5 |
| Spec score · AI Email Writing Tools | 8.2 (#10) | 8.2 (#11) |
| Integrations | The site lists Gmail, WhatsApp Web, LinkedIn, Outlook, Zoho, Slack, Freshdesk, and Zendesk for replying to emails and messages in the user's voice. | Kerna integrates with Gmail, Outlook, Calendar, Contacts and Sheets, and the pricing page lists shared mailboxes for Outlook. |
| Intended users | The pricing page describes the free plan as suitable for general tasks and Elite and Ultra as suitable for reasoning tasks. | Kerna describes itself as email automation for professionals and offers team plans for collaboration and larger organizations. |
| Privacy | The privacy notice says Gmail and Google Calendar data is used only for enabled draft features, is not used for advertising or AI training, and email bodies and calendar events are not stored on Jetwriter AI servers. | Kerna says email content is processed in memory and discarded after the request, with personal data redacted before content reaches the inference provider. |
| Product | Jetwriter AI is a personal AI writing assistant for writing emails and messages, chatting with webpages, fixing grammar, improving writing, and translating. | Kerna is an AI email assistant that works inside Gmail and Outlook. |
| Security | The home page says data is not shared with third parties or used for AI training and is encrypted in transit using TLS 1.2 or greater. | The trust page reports TLS 1.2 or higher in transit and AES-256 encryption at rest in Firestore. |
Plans
Jetwriter AI
- FreeFree
- Elite$18 a month
- Ultra$39 a month
- Elite$168 a year
- Ultra$349 a year
Kerna
- StarterFree
- Standard€12 a month
- Pro€22 a month
- Business€69 a month
- Enterprise€499 a month
In their own words
Jetwriter AI
Jetwriter AI is a personal writing assistant available through a browser extension and web app. It can help compose emails and messages, correct grammar, improve or translate writing, and summarize or explain selected text. Users can create a profile, define writing styles, and use memory based on earlier conversations. The service can search the web, read live pages, and chat with files in any format; it lists GPT 6 Series, Claude Opus and Sonnet, and Gemini Pro among its models. Integrations for replying in the user's voice include Gmail, WhatsApp Web, LinkedIn, Outlook, Zoho, Slack, Freshdesk, and Zendesk. Gmail auto-drafting is optional; drafts are saved for review, editing, and sending. Its privacy notice says Gmail and Calendar data is used only for enabled drafting features, not advertising or AI training, and that email bodies and calendar events are not stored on its servers. The free plan provides 15 regular model responses monthly and no advanced responses. Elite costs $18 a month; Ultra costs $39 a month. Chrome, Edge, Brave, Opera, and Vivaldi extensions are listed, while Safari and Firefox are marked as coming soon.
Kerna
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.