What Is BIMI?
TL;DR
BIMI, or Brand Indicators for Message Identification, is a standard that lets a domain publish a logo for supporting inboxes to display next to its authenticated mail. It requires an enforcing DMARC policy, so it is the last authentication step rather than the first.
What does BIMI require?
Three things have to be in place. The domain needs a DMARC policy at quarantine or reject, since a logo next to unverified mail would be worth forging. It needs the logo as an SVG Tiny Portable/Secure file hosted over HTTPS. And for most inbox providers it needs a Verified Mark Certificate from a certificate authority, which attests that the logo is a trademark you own.
The certificate is the part with a recurring cost and a lead time, because it is issued against a registered trademark rather than a domain.
Is BIMI worth it for cold outreach?
Rarely, and the reason is structural rather than technical. BIMI displays a logo for a brand a recipient already recognises, which is worth most for transactional and marketing mail to an existing audience. A first-touch cold email is going to someone with no prior relationship, so there is no recognition for the logo to trigger.
The DMARC enforcement BIMI requires is worth doing on its own merits either way. Treat BIMI as a brand-mail project and the enforcement work as the deliverability project that happens to unlock it.
Frequently asked questions
Gmail was the first at scale and remains the main one, with Yahoo, Fastmail and La Poste also supporting it. Microsoft Outlook does not display BIMI logos, so a large share of business recipients will not see one.