Hiwriter

Hiwriter is a Google Workspace add-on that writes emails and replies inside Gmail using OpenAI's GPT-3.5. You pick a topic, add a few details and choose a tone, and it produces a draft you can send, edit, translate or regenerate.

For replies, it reads the context of the email thread so the answer fits the conversation. You can describe yourself, the recipient and the subject to make the draft more personal, and generate as many variations as you like until one fits.

It works in Gmail on both desktop and mobile, and supports most languages, so you can write in one language and translate the result into another before sending. It is installed from the Google Workspace Marketplace.