How to add your email signature to emails Grok sends

If you already have a signature, check "How Grok sends email" for the route Grok takes to your mail: the route decides whether your mail app adds the signature or Grok has to. If you need one, make it free on Signatoro, then click "Copy signature" for your mail app or "Copy as text" for your request to Grok.

How Grok sends email

Grok reads, drafts and sends email through connectors, set up at grok.com/connectors. xAI's docs say the Gmail connector starts read-only: it composes drafts, and sends, replies and forwards, once write and send permissions are enabled. The Outlook connector drafts with an HTML body and sends, replies and forwards from a Microsoft work or school account. Both act on your mailbox from the conversation, outside Gmail's and Outlook's compose windows.

Google's Gmail API reference says a Gmail signature is included in messages composed in the Gmail web interface and is added to new emails only, and Outlook adds its signatures in its own compose window. An email Grok sends through a connector therefore carries no signature unless Grok writes one into the body; one sent email in your Sent folder shows which case is yours. Signatoro has found that the Gmail tool built into chat assistants drops every image from the HTML it is given, so the reliable signature for these emails is the text one.

Grok for Outlook, a Microsoft 365 add-in, works the other way: xAI says it writes real drafts in Outlook's compose window and nothing sends until you send. Outlook's own signature setting applies there. The xAI API's built-in tools are web search, X search, code execution, image generation and collections search, so email goes through a function you define, and your code adds the signature. xAI's docs do not describe a Grok setting for standing instructions, so a text signature goes into each request.

Add your signature to emails Grok sends

Grok for Outlook

1. Set your signature in Outlook with the Outlook guide, turned on for new messages and for replies and forwards.
2. Ask Grok for Outlook to draft the reply.
3. Check the draft in Outlook's compose window ends with your signature, once.
4. If it is missing in new Outlook, select "Signature" in the "Insert" group on the "Message" tab and choose your signature.
5. Send the email yourself.

The Gmail and Outlook connectors

1. On Signatoro, click "Copy as text".
2. In your request to Grok, add "End the email with this signature, exactly as written:" and paste the text below it.
3. Check the draft or the approval step shows those lines at the end before the email goes out.

If Grok saves a Gmail draft that you send from Gmail yourself, you can use Gmail's own signature instead: in the compose window, click "Insert signature" at the bottom and pick yours. In that case, leave the signature out of your request so the email does not end with two.

The xAI API and your own automations

1. Save your signature on the signature page.
2. Under "For tools and assistants", click "Generate API key". Store the key in your platform's secret store, and keep it out of prompts, chats and system prompts.
3. Before each send, have your code call GET https://signatoro.com/api/v1/signature with Authorization: Bearer <key>.
4. Append html after the HTML body and text after the plain-text body, then send through the Gmail API, Microsoft Graph or your mail library.

Signatoro's signature API guide has the full request, the responses and a Gmail API example. Each call returns the current version of the signature; free accounts have a monthly request limit, and people in a company on a plan have none.

Grok email signature questions

Can Grok send emails from my Gmail?

Grok can send from Gmail only after send permission is granted. xAI's docs say the Gmail connector's base connection is read-only, and drafts, sending, replying and forwarding are added when write and send permissions are enabled, which xAI says your organization's administrators do. The Outlook connector requests permission to send at sign-in. Connect both at grok.com/connectors.

For agents

• First work out your route. In Outlook's compose window (Grok for Outlook), the mail app adds the signature: write no closing block and never paste a second signature.
• Through the Gmail or Outlook connector, nothing adds a signature. End the body with the text signature the person gave you, exactly as given; if there is none, ask the person for it.
• Through your own code, fetch GET https://signatoro.com/api/v1/signature per send and append html or text, as the signature API guide describes.
• Never ask for, repeat or store a Signatoro API key in a conversation.

Sources

Checked against xAI's, Google's and Microsoft's own documentation on 2026-09-25:

• Connectors
• Gmail & Google Calendar
• Outlook Mail & Calendar
• Grok for Outlook
• Tools overview (xAI API)
• REST Resource: users.settings.sendAs (Gmail API)
• Create a Gmail signature
• How to add and change an email signature in Outlook