BIMI: Brand Logos in Email
What BIMI Is and How Brand Logos Appear
BIMI (Brand Indicators for Message Identification) is an email standard that lets a domain owner show its logo next to authenticated messages in supporting inboxes. The logo is referenced in DNS and fetched by the receiving provider, rather than attached to each message.
The domain owner publishes a DNS record that points to a logo file, typically in SVG format, hosted on a web server. The logo must follow a set of formatting rules from the BIMI specification so that it displays consistently. When a mailbox provider supports BIMI and the message passes its checks, it can show the logo beside the sender's name.
BIMI is a display feature, not a security mechanism. It does not stop phishing or spam, and a logo never proves that a message is trustworthy. Its purpose is to help recipients recognize genuine mail from a brand. Support also varies, because each mailbox provider decides whether and how to show BIMI logos.
Why BIMI Depends on an Enforced DMARC Policy
BIMI rests on email authentication. A receiver shows a brand logo only when the message is authenticated in a way it trusts. Most providers that support BIMI expect the domain's DMARC policy to be set to enforcement, meaning quarantine or reject, rather than none.
The reasoning is straightforward. If a domain only monitors authentication, anyone can still send mail that appears to come from it, and a logo would lend that false appearance credibility. Requiring enforcement means the logo is attached only to mail the domain has effectively vouched for. The wider picture of how the three methods combine is in SPF, DKIM and DMARC together.
Verified Mark Certificates and Logo Requirements
Some mailbox providers ask for a Verified Mark Certificate (VMC), a digital certificate issued by a certificate authority that confirms the sender has the right to use the logo, usually because it is a registered trademark. The certificate is referenced from the same DNS record as the logo. Providers that require it display the logo only when the certificate is valid.
A brand without a registered trademark may not be able to obtain a certificate, which limits where its logo can appear. Requirements vary by provider, and some may not require a certificate at all, so checking each provider's rules is the practical step.
Frequently asked questions
Does BIMI make email safer?
Not directly. BIMI is a display feature that shows a verified brand logo in supporting inboxes, so it can help recipients recognize genuine mail. Real protection comes from authentication such as DMARC, which BIMI depends on. Mailboxes that do not support BIMI show no logo at all, so the absence of a logo is not a warning sign.
Which mailbox providers display BIMI logos?
Support depends on each mailbox provider, and it has changed over time. Check the current documentation of the providers your audience uses, because a logo shown in one inbox may not appear in another. Requirements such as certificates can also differ between providers.