Shortwave email signature
Shortwave takes your signature from Gmail. Set your Signatoro signature as the Gmail default, and the emails you write in Shortwave carry it.
Where Shortwave gets your signature
Shortwave is an email client for Gmail with an AI Assistant built in. It syncs the default signature from your Gmail account, so your signature lives in Gmail and Shortwave reads it from there.
When you change the signature in Gmail, Shortwave picks up the new version within a few minutes. In the compose window Shortwave folds the signature away to save space, and the full signature goes out with the email.
Set your Signatoro signature in Gmail
Shortwave reads the signature Gmail marks as the default for both new emails and replies. A signature set for one of the two is the usual reason it is missing in Shortwave.
- Build your signature on Signatoro and click "Copy signature". It copies the signature formatted, with its logo or photo.
- In Gmail on a computer, open Settings (the gear) > "See all settings" > "General" and scroll to "Signature".
- Click "Create new", name it, and paste the signature into the text box.
- Under the signature defaults, choose it for new emails and for replies and forwards, then click "Save Changes".
- Give Shortwave a few minutes, open a new email there, and click the "..." button at the bottom of the compose box to see the signature.
Logos, photos and the "Sent with Shortwave" line
Shortwave's signature guide asks for images at a publicly accessible web address, as PNG or JPG files under 100KB. A photo or logo uploaded to Signatoro is hosted at a public web address.
Shortwave can add a "Sent with Shortwave" line to the emails you send. To turn it off, go to Settings > Compose > Sent with Shortwave.
AI drafts from the Shortwave Assistant
The Shortwave AI Assistant writes emails with you. An instant AI reply gives you a full draft for the thread you are reading in one click, written in your style by Ghostwriter, which learns from the emails you have sent. "Improve draft" in the compose box rewords a draft you started.
You review each draft in the compose box and send it from your Gmail address. Before you send the first one, click "..." at the bottom of the draft and check that your signature is there.
Connect Signatoro to the Shortwave Assistant
Shortwave's Assistant connects to remote MCP servers, and Signatoro runs one. Connected, the Assistant can read your saved signature details and change your signature from a chat. MCP support in Shortwave is in beta, and integrations come with the Business, Premier and Max plans.
- Open the AI integrations page in Shortwave's settings, click "Add custom integration" and choose "Remote MCP server".
- Name it Signatoro, enter `https://signatoro.com/mcp` as the endpoint URL and click "Save".
- Turn on the toggle, then sign in to Signatoro and approve when it asks. A green dot on the integration card means the connection works.
- Shortwave adds your Gmail signature to the compose box. Tell the Assistant "Remember that Shortwave adds my signature, so leave the sign-off and signature out of drafts", which saves it as an AI memory.
- After you change your signature on Signatoro, paste the new version into Gmail so Shortwave syncs it.
Shortwave email signature questions
How do I add a signature in Shortwave?
Shortwave uses the default signature from your Gmail account. Paste your signature into Gmail under Settings > See all settings > General, set it as the default for new emails and replies, and save. Shortwave picks it up within a few minutes.
Why is my signature missing in Shortwave?
Shortwave collapses the signature in the compose window: click "..." at the bottom to see it. If it is missing there, set it in Gmail as the default for both new emails and replies and forwards.
Why do the images in my Shortwave signature fail to show?
Shortwave needs signature images at a publicly accessible web address, as PNG or JPG files under 100KB. Images uploaded to Signatoro are hosted at a public address.
How do I remove "Sent with Shortwave" from my emails?
Go to Settings > Compose > Sent with Shortwave and turn the setting off.
Sources
Checked against Shortwave's documentation on October 11, 2026.