Glossary
EMAIL AUTH

BIMI

Brand Indicators for Message Identification — a DNS TXT record letting DMARC-authenticated senders show their logo next to messages in Gmail, Yahoo, and Apple Mail.

BIMI (Brand Indicators for Message Identification) publishes a DNS TXT record that maps your DMARC-authenticated domain to a logo (SVG) that supporting mail clients display in the message list. Gmail, Yahoo, AOL, Apple Mail, and Fastmail support it.

Record Format

default._bimi.example.com.  TXT  "v=BIMI1; l=https://example.com/logo.svg; a=https://example.com/vmc.pem"

Prerequisites

  • DMARC at p=quarantine or p=reject (BIMI requires enforcement — no p=none)
  • SVG logo conforming to the “SVG Portable / Secure” tiny profile
  • A Verified Mark Certificate (VMC) or Common Mark Certificate (CMC) — a paid cert from Entrust or DigiCert proving the trademark is yours

Cost

VMC issuance runs $1.5k-$2k/year. CMC (for older, less-formally-trademarked marks) is cheaper. Both require a registered trademark on file with USPTO or an equivalent registry.

Why Bother

Studies from Fastmail and Verizon Media show 10–39% higher engagement on BIMI-verified messages. It’s the visual signal that the sender is really who they claim.

Read what DMARC is, check the DKIM glossary entry, and see the SPF glossary entry.

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