Microsoft weights sender reputation via SNDS and JMRP, and rejects unauthenticated bulk mail to consumer Outlook.com addresses.
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.
Setting up BIMI for Outlook and Microsoft 365#
- 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"How Outlook and Microsoft 365 reports results#
Open a delivered test message in Outlook and Microsoft 365 and view the original or headers. Look for Authentication-Results and any provider-specific verdict headers. Use the provider's sender dashboard for aggregate reputation.
Common mistakes#
- Publishing BIMI while DMARC is still at p=none; providers ignore the record.
- Uploading a standard SVG exported from a design tool; it must be the Tiny PS profile with no scripts or external references.
- Hosting the logo on a non-HTTPS URL or behind a redirect.
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.
Does Outlook and Microsoft 365 require BIMI?
Microsoft weights sender reputation via SNDS and JMRP, and rejects unauthenticated bulk mail to consumer Outlook.com addresses. Treat BIMI as required for any meaningful volume.