Jetwriter AI

Browser-based AI writing assistant that lives in Gmail, WhatsApp, LinkedIn, and Outlook and learns your past replies.

Freemium· Free tier; paid plans unlock premium models and Gmail learningWritingMulti-model (GPT-5, Claude Opus/Sonnet, Gemini Pro)

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Best for

Pick Jetwriter if you live in Gmail and want a single in-page assistant that can switch between Claude, GPT-5, and Gemini without leaving the tab.

Skip if

Skip it if you need an API, on-prem deployment, or a writing tool that works equally well outside the Chrome/Chromium ecosystem.

Jetwriter is a Chrome extension and companion web app that drops a multi-model writing assistant on top of whatever site you're on. It will draft emails, rewrite messages, fix grammar, summarize pages, translate text, and let you chat with the document or webpage in front of you. The deepest hooks are in Gmail, where it ingests your past threads to mimic your tone, but it also operates inside WhatsApp Web, LinkedIn, Outlook, Slack, and Zendesk.

Under the hood it routes between GPT-5, Claude (Opus and Sonnet), and Gemini Pro, so you're picking a model per task rather than being locked into one lab. It's pitched at individual professionals and small teams who spend a meaningful chunk of their day in an inbox or a CRM and want a single shortcut instead of bouncing into ChatGPT. The extension itself is small (<1MB), there is a free tier to try it, and paid tiers unlock the heavier models and the Gmail learning features.

There's no public API and no open-source component, so this is firmly an end-user productivity layer rather than something you'd build on. Voice input, custom writing styles, and live web search round it out into a fairly complete "AI everywhere I type" tool.

Editor's take

A solid, unflashy entry in the in-browser AI writing tier. The multi-model routing and Gmail tone-learning are the real selling points over Grammarly-style fixers. It won't replace a dedicated long-form writing tool, but for inbox triage and quick rewrites it earns its keyboard shortcut.

— The AI Tool Bible editorial team