ForthWrite

ForthWrite is a Chrome extension that drafts email replies inside Gmail and Outlook, pulling from your sent mail history to match your tone, sentence rhythm, and sign-offs. The vendor describes a three-step flow: install the extension, set a persona in two minutes, then click Generate Draft on any thread. The reply it produces reads the full thread — including forwards and nested messages — and addresses every open question, not just the last message. Every draft you accept and every edit you make feeds a private training set, and a performance dashboard tracks acceptance rate, similarity score, and edit distance so you can see the voice match tightening over time.

The differentiating feature is model choice. ForthWrite supports nine LLM providers — OpenAI, Claude, Gemini, Grok, DeepSeek, Mistral, Perplexity, Cohere, and LibreChat — and lets you bring your own API key. You choose the model per use case: the docs suggest Claude for tone and Grok when cost is the constraint. No other email drafting tool in this category offers that provider flexibility at the point of draft generation. The vendor states your BYOK credentials are encrypted at rest, your sent mail is stored in an isolated account and never used to train shared models, and a one-click data wipe is available at any time.

ForthWrite fits professionals with high personal email volume who want drafts that sound like them without copy-pasting threads into a chat interface. Community feedback on G2 and the Chrome Web Store points to time savings and tone quality as the standout outcomes. Where it breaks: there is no API, so the tool cannot be embedded in a team helpdesk, CRM, or automation pipeline. It is also a solo instrument — shared inboxes and team-level voice consistency are outside what the product addresses. Teams that need outbound email automation at scale or multi-user inbox tooling will need a different solution.