With SendinBlue, you can customize your senders' DKIM signature with your domain name, whether your campaigns are sent via SendinBlue shared IP addresses or via dedicated IP addresses.
To do this, go to Settings, in the Your Senders box, click on Configure.
or in the Senders section of the My account menu
Then go to the list of your domains. Select the domain with which you wish to sign your emails (or create one), click on the Manage tab and select Edit from the pull-down menu.
The sender editing window will then open. By default, your emails are signed by the domain name associated with the dedicated IP address.
To customize your DKIM signature, check the box: I would like to use this domain name to sign my emails.
Now enter the domain name you wish to use to sign your emails (in our example, we have entered the subdomain tutorial.sendinblue.com). When you click on the save button, a pop-up will appear with the DNS entries to be configured.
Once the configuration is complete, a green check will appear next to the DKIM, SPF and Verify Code keys (and possibly DMARC).
Now click on DONE.
From now on the emails sent by this sender will be signed by your own domain name!