ForthWrite

ForthWrite is a Chrome extension for people who live in their inbox: it watches the replies you actually send and builds a model of your writing voice, then drafts responses that sound like you instead of like a generic AI.

You connect Gmail or Outlook on the web in about two minutes, and from then on opening a thread offers a draft in your tone, with filler phrases, sign-offs, and vocabulary matching your history.

The free tier is genuinely usable at 10 drafts per week with no credit card and no API key required, which makes it easy to judge the voice quality before paying.\n\nThe paid tiers are where ForthWrite gets serious about volume.

Standard adds a sharper model, a custom system prompt for persona control, and drafts that adapt to the recipient and the intent of the email, so a follow-up reads differently from a first reply.

Pro turns the inbox into a batch operation: replies are auto-drafted before you open the thread, dozens of stale conversations can be cleared in parallel, and an edit-supervision loop keeps refining the model every time you tweak a draft.

The Prompt Lab adds version control and A/B testing of prompts, and performance analytics chart whether your response quality is actually improving.\n\nFor marketers and sales people who send dozens of personalized emails a day, the value is writing speed without sounding like a bot.

The honest caveats: it only works in Gmail and Outlook on the web through a Chrome extension, and the free cap of 10 drafts a week disappears quickly for heavy senders.

Treat Pro's auto-draft as a strong first pass that still needs a human read before hitting send.