To send email using Thunderbird you will have to modify your outgoing server settings in Thunderbird accordingly. Additionally you can modify settings in Thunderbird that will allow you to include an SMTP API header in your emails if you wish to leverage categories or other features of the SMTP API when sending mail via the Thunderbird client.

Start by going to: ‘Tools’ -> ‘Account Settings’

The Settings that need to be entered include:

  • Description - SendGrid Connection
  • Server Name - smtp.sendgrid.net
  • Port - 465
  • Connection security - SSL/TLS
  • Authentication method - Normal password
  • User Name - sendgrid_username

Incorporating SMTP API headers requires the following.

  • Select Tools | Options (Win) or Thunderbird | Preferences (Mac) from the menu in Thunderbird.
  • Open the “Advanced” category.
  • Go to the “General” tab.
  • Click “Config Editor”.

  • Enter “mail.compose.other.header” under “Filter:”
  • Double-click mail.compose.other.header.
  • Enter “X-SMTPAPI”
  • Click OK.
  • Close the configuration editor and preferences dialog.

  • Restart Thunderbird
  • Create a mail message and just like you would add a CC or BCC to your email, click the drop down option that will now allow you to add a header of the type “X-SMTPAPI” in addition to “To”