Fastmail HTML email signature installation guide

Fastmail supports HTML email signatures through its web settings. You’ll paste the rendered Mirosign signature into the signature editor.

1Turn on rich text (if needed)

Go to Settings → Mail preferences and make sure your default message format allows rich text — this is what enables the formatting in signatures.
2Create and copy your signature
1. Design and save your signature in Mirosign.
2. Click Download HTML, open the file in a browser, then select all (Ctrl/Cmd + A) and copy (Ctrl/Cmd + C). Use Ctrl/Cmd + A rather than dragging, so you capture the whole signature.
3Paste into Fastmail
1. Go to Settings → My email addresses and open the Signatures tab (in some layouts: Signatures & Compose).
2. Click Edit next to the address you want, click inside the signature box and paste (Ctrl/Cmd + V).
3. Click Save, then compose a test email.
Design your email signature