Why BIMI exists
Spam filtering is invisible to users — recipients never see the auth headers, so they have no way to distinguish a legitimate sender from a successful spoof at a glance. BIMI is the first widely-deployed mechanism that surfaces authentication state visually.
Receivers that honour BIMI (Gmail since 2021, Apple Mail iOS 16+, Yahoo) only display the logo when the message passes DMARC at enforcement strength. So the BIMI badge is also a deliverability proof — it's only visible once your authentication is in order.
What a BIMI record looks like
A TXT record at default._bimi.<domain> pointing at an SVG logo and (for Gmail) a Verified Mark Certificate (VMC).
default._bimi.yourdomain.com. TXT "v=BIMI1; l=https://yourdomain.com/bimi-logo.svg; a=https://yourdomain.com/bimi-vmc.pem"The VMC requirement
Gmail requires a Verified Mark Certificate (VMC) from a recognised certificate authority (DigiCert or Entrust at present) before it displays your BIMI logo. The VMC is issued only against a registered trademark and costs ~$1500/year.
Apple and Yahoo display BIMI logos without a VMC — TXT record + SVG is enough. So BIMI works as a brand-recognition lever on iOS / Apple Mail without the certificate cost.
The SVG requirements are picky
BIMI logos must be SVG Tiny PS — a stripped-down SVG profile. No external references, no animation, no embedded raster, no foreign objects. Maximum 32 KB.
Generating a compliant logo from an existing brand SVG is usually a 30-minute exercise in your favourite vector editor (Illustrator → Save As → SVG Tiny). The validator at bimigroup.org will tell you exactly what to remove.
When BIMI is worth doing
You publish DMARC at p=quarantine or p=reject (BIMI is ignored otherwise).
You send enough volume that brand recognition in the inbox materially affects engagement.
You have a registered trademark and budget for a VMC if you want Gmail support.
Without these, BIMI is a nice-to-have. With them it is a measurable engagement lever.