BIMI Checker

What is BIMI?

Brand Indicators for Message Identification (BIMI) is an email standard that allows organizations to display their brand logo alongside authenticated messages in recipients' inboxes. It provides a visual indicator of authenticity, helping users identify legitimate emails from trusted senders while reinforcing brand recognition.

BIMI builds on existing email authentication by requiring a valid DMARC policy at enforcement level. This creates a virtuous cycle: organizations must secure their email infrastructure before they can benefit from brand visibility.

Prerequisites for BIMI

Before implementing BIMI, your domain must have:

1. DMARC at enforcement – Your DMARC policy must be set to p=quarantine or p=reject. Policies of p=none do not qualify.

2. SPF and DKIM alignment – Messages must pass DMARC alignment through either SPF or DKIM authentication.

3. Good sending reputation – Mailbox providers may consider your domain reputation when deciding whether to display your logo.

Without proper email authentication, BIMI logos will not appear regardless of your BIMI record configuration.

Logo Requirements

BIMI has specific requirements for logo files:

• SVG Tiny Portable/Secure format – Logos must be in SVG P/S format, a constrained version of SVG designed for security. Standard SVG files will not work.

• Square dimensions – The logo must be square and centered, typically displayed in a circle by mailbox providers.

• Hosted via HTTPS – The logo file must be publicly accessible over HTTPS with a valid certificate.

• No embedded scripts – The SVG P/S format prohibits JavaScript and external references for security reasons.

Many organizations need to convert their existing logos to meet these requirements.

Verified Mark Certificates

Some mailbox providers require a Verified Mark Certificate (VMC) before displaying BIMI logos:

• What VMCs do – They cryptographically verify that your organization owns the trademark for the logo being displayed.

• Who requires them – Gmail requires a VMC, while other providers like Yahoo display logos without one.

• How to obtain one – VMCs are issued by certificate authorities after trademark verification. Your logo must be a registered trademark.

• Certificate cost – VMCs involve annual fees and a validation process similar to extended validation SSL certificates.

Mailbox Provider Support

BIMI adoption varies across email providers:

• Gmail – Supports BIMI but requires a VMC for logo display.
• Yahoo/AOL – Displays BIMI logos without requiring a VMC.
• Apple Mail – Added BIMI support in iOS 16 and macOS Ventura.
• Fastmail – Supports BIMI logo display.

Provider implementations may differ in how logos appear, including shape masking and display contexts.

What MailHealth Checks

Our BIMI checker validates your configuration by examining:

• Record existence – Confirms a BIMI TXT record is published at default._bimi.yourdomain.com.
• Record syntax – Verifies the version tag and required fields are properly formatted.
• Logo accessibility – Checks that the logo URL is reachable and serves a valid SVG file.
• DMARC prerequisite – Verifies your DMARC policy is at enforcement level as required by BIMI.
• VMC presence – Indicates whether a Verified Mark Certificate is specified in your record.

Implementing BIMI rewards your email authentication efforts with visible brand presence in the inbox, building trust with recipients while differentiating your messages from potential impersonators.