BIMI Explained

Brand Indicators for Message Identification (BIMI) allows organizations to display their brand logo within an email.

Example of BIMI logo being displayed for OpenAI in Google Mail.

BIMI works in conjunction with DMARC. To display a BIMI logo, a domain must have a DMARC policy of either quarantine or reject, and the email must pass DMARC authentication.

v=BIMI1; l=https://static.example.com/brand/example-logo.svg; a=https://static.example.com/brand/example.vmc

Example of a BIMI record with a logo URL and certificate URL.

BIMI is published as a DNS TXT record, defaulting to default._bimi.yourdomain.com.
To prevent brand impersonation, some email providers (Google/Apple) require proof of ownership via a certificate. The two supported certificate formats are Verified Mark Certificate (VMC) and Certified Mark Certificate (CMC). VMC requires a legally registered trademark, but has broader support.