What is BIMI? Complete Guide to Brand Indicators for Message Identification

Brand Identity & Security

BIMI (Brand Indicators for Message Identification) is an email specification that displays your brand's logo next to your emails in recipients' inboxes. When properly configured, your verified logo appears instead of a generic avatar or initial, making your emails instantly recognizable.

How BIMI Works

BIMI builds on top of email authentication. Here's the chain:

1. You send an email from your domain
2. The recipient's mail server checks your DMARC policy
3. If DMARC passes with an enforcement policy (quarantine or reject), the server looks up your BIMI record
4. Your BIMI record points to your logo file (and optionally a certificate)
5. The email client displays your logo next to your message

BIMI Requirements

DMARC Enforcement

Your domain must have DMARC configured with an enforcement policy:

• p=quarantine — minimum requirement
• p=reject — recommended

A p=none policy (monitoring only) doesn't qualify. Check your current DMARC status with a DMARC checker.

SVG Logo File

Your logo must be:

• SVG Tiny Portable/Secure (SVG-PS) format — not regular SVG
• Square aspect ratio — will be displayed in a circle
• Hosted on HTTPS — HTTP URLs won't work
• Publicly accessible — no authentication required

The SVG-PS format has security restrictions that prevent embedded scripts or external references. Most SVG files need conversion.

Verified Mark Certificate (VMC) — Sometimes Required

Some email providers require a VMC to display logos:

A VMC is a certificate that verifies you own the trademark for the logo. It's issued by certificate authorities like DigiCert or Entrust after verifying trademark ownership.

BIMI Record Structure

A BIMI record is a DNS TXT record at a specific location:

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

Record Components

Selector

The default selector is standard, but you can use different selectors for different purposes:

• default._bimi.example.com — standard selector
• brand1._bimi.example.com — custom selector for a specific brand

Setting Up BIMI

Step 1: Verify DMARC Enforcement

Check that your DMARC policy is at enforcement level:

_dmarc.yourdomain.com TXT "v=DMARC1; p=reject; rua=mailto:dmarc@yourdomain.com"

If you're still at p=none, you'll need to move to p=quarantine or p=reject first. This typically requires:

1. Monitoring DMARC reports to identify legitimate senders
2. Ensuring all legitimate sources pass SPF or DKIM
3. Gradually tightening the policy

Step 2: Prepare Your Logo

Convert your logo to SVG Tiny Portable/Secure format:

1. Start with a square version of your logo
2. Use a BIMI-specific converter (several free tools exist)
3. Validate the output meets SVG-PS requirements
4. Host the file on HTTPS

Step 3: (Optional) Obtain a VMC

If you need Gmail/Apple Mail support:

1. Register your logo as a trademark (if not already)
2. Apply for a VMC from DigiCert or Entrust
3. Complete their verification process
4. Host the certificate file on HTTPS

Step 4: Create DNS Record

Add the TXT record to your DNS:

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

With a VMC:

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

Step 5: Test Your Setup

Use a BIMI checker to verify:

• DNS record is published correctly
• Logo URL is accessible
• Logo format is valid
• VMC (if present) is valid

Common BIMI Issues

Logo Not Displaying

Possible causes:

• DMARC policy is p=none
• SVG file isn't in SVG-PS format
• Logo URL returns 404 or requires authentication
• VMC missing (for Gmail/Apple Mail)

BIMI Record Not Found

Check:

• Record is at correct location (default._bimi.domain.com)
• TXT record type (not CNAME)
• DNS propagation (may take 24-48 hours)

Invalid Logo Format

The SVG-PS format is strict. Common issues:

• Embedded fonts (must be converted to paths)
• External references (not allowed)
• JavaScript or animation (not allowed)
• Non-square dimensions

BIMI and Email Deliverability

BIMI doesn't directly improve deliverability, but it has indirect benefits:

Recognition: Recipients recognize your brand, making them more likely to open and engage with your emails.

Trust signal: A verified logo suggests legitimacy, potentially reducing spam reports.

DMARC enforcement: The DMARC requirement means BIMI adopters already have strong authentication — which does help deliverability.

However, BIMI is primarily a branding feature, not a deliverability tool. If you're having deliverability issues, focus on SPF, DKIM, and DMARC first.

BIMI Without a VMC

You can still benefit from BIMI without the expensive VMC:

• Yahoo and AOL display logos without VMC verification
• Some corporate email clients may display logos
• Future expansion — more providers may support unverified logos

Setting up BIMI now (even without a VMC) positions you for when/if requirements relax or more providers support it.

Monitoring Your BIMI Setup

BIMI can break when:

• Logo URL changes or becomes inaccessible
• VMC expires (annual renewal required)
• DMARC policy changes to p=none
• DNS records are accidentally modified

Regular monitoring catches these issues before they affect your brand presentation.

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