BIMI (Brand Indicators for Message Identification)

BIMI allows organizations to display their brand logo next to authenticated emails in supporting email clients.

How BIMI Works

The Benefit

When properly configured, your logo appears in email clients:

• Next to your emails in the inbox
• In the message view
• Increases brand recognition
• Signals email authenticity to recipients

Requirements

BIMI requires:

1. DMARC at p=quarantine or p=reject
2. BIMI DNS record with logo URL
3. Logo in correct format
4. Optionally, a VMC (Verified Mark Certificate)

DMARC at enforce
      │
      ▼
  BIMI Record
      │
      ▼
  Logo URL ───> Logo File (SVG)
      │
      ▼
  VMC (optional) ───> Certificate Authority

BIMI Record Format

BIMI records are TXT records at:

default._bimi.example.com

Example:

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

Record Tags

Tag	Required	Description
v	Yes	Version (BIMI1)
l	Yes	Logo URL
a	No	VMC certificate URL

Tag Details

Version (v):

• Always BIMI1

Logo (l):

• HTTPS URL to your logo
• Must be publicly accessible
• SVG Tiny PS format preferred

Authority (a):

• URL to VMC certificate (PEM format)
• Required by some providers (Google)
• Optional for others

Logo Requirements

Format: SVG Tiny PS

Most providers require SVG Tiny Portable/Secure:

• Vector format (not raster)
• No scripts or animations
• No external references
• Square aspect ratio
• Specific SVG profile

SVG Tiny PS Requirements

<?xml version="1.0" encoding="UTF-8"?>
<svg version="1.2" baseProfile="tiny-ps"
     xmlns="http://www.w3.org/2000/svg"
     width="512" height="512"
     viewBox="0 0 512 512">
  <!-- Logo content -->
</svg>

Must include:

• version="1.2"
• baseProfile="tiny-ps"
• Square dimensions

Must NOT include:

• JavaScript
• External references
• Animations
• Embedded raster images

File Requirements

Requirement	Value
Format	SVG Tiny PS
Size	Max 32KB
Dimensions	Square (e.g., 512x512)
Hosting	HTTPS required
Accessibility	Public, no authentication

Verified Mark Certificate (VMC)

What is a VMC?

A VMC is a certificate that verifies:

• You own the trademark for the logo
• The logo is registered
• Issued by a trusted Certificate Authority

When is VMC Required?

Provider	VMC Required
Google/Gmail	Yes
Yahoo	Yes
Apple Mail	No
Fastmail	No

Obtaining a VMC

1. Register your trademark (if not already)
2. Choose a VMC provider:
   • DigiCert
   • Entrust
3. Submit application with trademark proof
4. Receive VMC (PEM file)
5. Host VMC at HTTPS URL

VMC Cost

VMCs typically cost $1,000-1,500/year and require:

• Registered trademark
• Domain verification
• Organization validation

Implementation Steps

Step 1: Ensure DMARC Compliance

BIMI requires DMARC at enforcement level:

v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com

or

v=DMARC1; p=reject; rua=mailto:dmarc@example.com

Step 2: Create Your Logo

1. Design or obtain your logo
2. Convert to SVG Tiny PS format
3. Ensure it meets all requirements
4. Test with BIMI validators

Step 3: Host Logo (and VMC)

1. Upload to your web server
2. Ensure HTTPS accessibility
3. Set correct Content-Type headers
4. Test public accessibility

Step 4: Add DNS Record

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

With VMC:

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

Step 5: Verify

1. Wait for DNS propagation
2. Send test emails to supporting clients
3. Verify logo displays correctly

Provider Support

Full Support

Provider	VMC Required	Notes
Gmail	Yes	Requires VMC
Yahoo Mail	Yes	Requires VMC
Apple Mail	No	iOS 16+
Fastmail	No	Desktop and mobile

Partial/Coming

• Outlook/Microsoft: In development
• Others: Varies

Troubleshooting

Logo Not Displaying

1. Check DMARC: Must be p=quarantine or p=reject
2. Verify DNS record: Correct format and syntax
3. Test logo URL: Must be publicly accessible
4. Validate SVG: Must be SVG Tiny PS format
5. Check VMC: Required for Gmail/Yahoo

SVG Validation Errors

Common issues:

• Wrong SVG profile (must be tiny-ps)
• Contains scripts or animations
• External references
• Non-square dimensions
• File too large

DNS Issues

• Record at wrong subdomain
• Missing v=BIMI1 version tag
• Invalid URL in l tag

BIMI Without VMC

For providers that don't require VMC:

v=BIMI1; l=https://example.com/logo.svg

This works with:

• Apple Mail
• Fastmail
• Other non-VMC-requiring clients

For Gmail/Yahoo without VMC:

• Logo won't display
• No error, just no logo

Best Practices

Do

✅ Reach DMARC enforcement first
✅ Use SVG Tiny PS format
✅ Test with multiple providers
✅ Keep logo simple and recognizable
✅ Use HTTPS for all URLs \

Don't

❌ Deploy BIMI before DMARC enforcement
❌ Use complex SVG features
❌ Use raster images (PNG/JPG)
❌ Forget to renew VMC annually
❌ Use non-square logos

Example Configurations

Basic (No VMC)

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

With VMC

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

Using a CDN

default._bimi.example.com  TXT  "v=BIMI1; l=https://cdn.example.com/bimi/logo.svg"

Tools and Resources

BIMI Validators

• BIMI Group Inspector
• MXToolbox BIMI Lookup
• MailShield BIMI check

SVG Converters

Several tools can convert logos to SVG Tiny PS:

• Adobe Illustrator (with export settings)
• BIMI-specific converters
• Professional design services

VMC Providers

• DigiCert
• Entrust

MailShield BIMI Features

MailShield helps with BIMI:

1. DNS Validation - Checks record syntax
2. Logo Verification - Fetches and validates logo
3. Format Check - Verifies SVG Tiny PS compliance
4. Monitoring - Alerts on configuration issues