What BIMI is#
BIMI (Brand Indicators for Message Identification) is a DNS record that points to a brand's logo so mailbox providers can display it next to authenticated messages. It depends on DMARC enforcement and, at Gmail and Apple, on a Verified Mark Certificate.
Why it matters#
A verified logo increases open rates and trust, and the DMARC prerequisite forces a domain to finish its authentication work. It is also a visible signal that a message is not a phish.
How mailbox providers use it#
Gmail, Microsoft, and Yahoo combine authentication results, sender reputation, and recipient engagement into a placement decision made per message. BIMI feeds directly into that model, and weaknesses compound with other signals.
How to measure the impact#
- Baseline inbox placement with seed tests before any change.
- Make one change at a time and hold volume steady.
- Re-test after 48 to 72 hours; provider models need time to update.
- Track Postmaster Tools and SNDS alongside your seed results.
Improving it#
- Reach DMARC p=quarantine (pct=100) or p=reject on the sending domain.
- Produce your logo as an SVG Tiny 1.2 Portable/Secure file, square, centered, with a solid background.
- Obtain a VMC or CMC from an approved certificate authority if you want display in Gmail and Apple Mail.
- Publish default._bimi.yourdomain.com with l= (logo URL) and a= (certificate URL).
- Validate with a BIMI inspector and send a test to Gmail, Yahoo, and Apple seed accounts.
default._bimi.example.com. IN TXT "v=BIMI1; l=https://example.com/brand/logo.svg; a=https://example.com/brand/vmc.pem"Frequently asked questions#
Does BIMI work without a VMC?
Yahoo and Fastmail display BIMI logos with DMARC enforcement alone. Gmail and Apple require a VMC or CMC.
What image format does BIMI require?
SVG Tiny 1.2 Portable/Secure. No PNG, JPG, or standard SVG.
Does BIMI improve deliverability?
Not directly. Its prerequisite, DMARC enforcement, does. The logo mainly lifts engagement and trust.