What it is
Brand Indicators for Message Identification is a DNS record pointing at your logo. Participating receivers — Gmail, Yahoo, Apple Mail and others — display that logo next to your messages in the inbox rather than a generic avatar or an initial.
It lives at default._bimi.yourdomain.com and points to an SVG file, plus optionally a certificate proving you own the mark.
The prerequisites
BIMI does nothing until DMARC is at quarantine or reject. This is deliberate — the logo is a trust signal, so it is only granted to domains that have actually locked down who can send as them. p=none domains get nothing.
The logo itself must be SVG Tiny Portable/Secure, a restricted profile of SVG. A standard export from a design tool will usually be rejected and needs converting.
VMCs and whether you need one
Gmail requires a Verified Mark Certificate — proof from a certificate authority that you own the trademark — before it will display your logo. VMCs cost real money annually and require a registered trademark. Some other receivers will display a BIMI logo without one.
For cold email specifically this is rarely worth it. Your secondary sending domains are not brands anyone recognises. BIMI is worth the effort on your primary domain, where recipients already know who you are.
Check yours
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Common questions
Does BIMI improve deliverability?
Not directly — it is a display feature, not a filtering signal. Indirectly it helps, because the DMARC enforcement it requires genuinely does improve placement, and a recognisable logo improves open rates.
Do I need a trademark?
For Gmail, effectively yes, because the VMC requires one. Without a VMC you can still publish BIMI and some receivers will honour it.
Should I set up BIMI on cold email domains?
No. Secondary sending domains are unrecognised by definition, and the VMC cost per domain would be absurd. Put it on your main brand domain.
Related concepts
If this is the thing going wrong
The pages explain it. If you would rather it was simply fixed, that is the work I do.