Definition
BIMI, acronym for Brand Indicators for Message Identification, is a way to display your logo next to your sender name in your recipient’s mailbox.
This technology allows brands to choose their logo themselves, instead of MailBox Providers. For the moment, Yahoo and AOL support this feature. Gmail also supports this feature but some steps are required to validate your brand, you can find more information here.
How to use BIMI?
Create a large square logo in SVG format (512 * 512 pixels, for example). However, even if it is square, chances are it will be displayed in a circle in different interfaces, so avoid putting important information in the corners.
The first example is correct, the second also but not very readable, and the third not, because the corners will be cropped.
Try to use a “simple” version of your logo; if there are too many details, those will not be visible, and it will look quite bad. Try to use a white or light background to get a consistent rendering on the different webmails and mobile apps.
Hosting of the logo
Once this logo has been created, host the SVG file on an HTTPS environment, publicly accessible from the Internet, ideally somewhere on your website.
DMARC, with a restrictive policy
DMARC allows you to announce a security policy to be applied when your domain name is used without your knowledge to send emails. DMARC requires you to have SPF or DKIM correctly configured on the domain in question. Within the framework of BIMI, it is necessary that the policy implemented is of type p = reject or p = quarantine.
DMARC is more effective in protecting your domain and all of its subdomains if you configure it on your organizational domain (the main domain, therefore mydomain.com, and not only on news.mydomain.com).
BIMI
A TXT type DNS record must be added to the domain concerned by the logo:
default._bimi.sending.domain.tld. TXT "v=BIMI1; l=https://url-of-the/logo.svg;"
If the BIMI record is applied to the organizational domain, then all subdomains of the organizational domain will be considered to have the same record. However, a specific record configured on one of the subdomains will have priority.
However, it is possible that even with everything configured correctly, your logo will not appear in the interfaces of participating Mailbox providers. There can be a number of reasons for this, the most obvious being that your brand is not considered related to your sending domain by the MailBox Providers in question. It may then be necessary to contact them for this to work.
This is the list of MailBox Providers that support BIMI.