Definition
BIMI (Brand Indicators for Message Identification) is an email specification that enables brands to display their verified logo in supported email clients' inboxes. When a recipient sees your logo next to your email, it builds trust, increases recognition, and can improve engagement rates. BIMI works alongside your existing email authentication stack.
The standard requires senders to have DMARC enforcement at quarantine or reject level, plus a Verified Mark Certificate (VMC) for the logo in most implementations. The logo is typically an SVG Tiny 1.2 file hosted at a publicly accessible URL and published as a DNS TXT record on the sending domain.
How BIMI Works
BIMI relies on existing email authentication protocols. When a mailbox provider receives an email, it checks for BIMI by querying a DNS TXT record at default._bimi.<domain>. If the record exists, the provider validates the email passed DMARC authentication at quarantine or reject policy, then retrieves and displays the brand's logo.
BIMI TXT Record: v=BIMI1; l=https://example.com/logo.svg; a=https://example.com/certificate.pem
| Component | Description |
|---|---|
| v | BIMI version (currently BIMI1) |
| l | URL location of the SVG logo |
| a | URL of the VMC certificate (optional for some providers) |
Which Email Clients Support BIMI
BIMI adoption is growing but is still limited to specific providers:
| Email Client | Support Status |
|---|---|
| Gmail | Full support (display logos for BIMI-enabled senders) |
| Apple Mail | Support in iOS 17+ and macOS Sonoma+ |
| Yahoo Mail | Full support (pioneered BIMI adoption) |
| Fastmail | Full support |
| Proton Mail | Support added in 2025 |
| Outlook (web) | Limited testing, not widely rolled out |
| Outlook (desktop) | Not supported |
Requirements for BIMI Implementation
- DMARC enforcement: DMARC policy must be set to
p=quarantineorp=reject. Ap=nonepolicy will not pass BIMI validation. - SPF or DKIM pass: The email must pass at least one of SPF or DKIM (alignment is not required for BIMI, but DMARC passing is).
- SVG logo: Must be a square SVG Tiny 1.2 file, typically less than 32 KB, with no external references.
- VMC (optional but recommended) : A Verified Mark Certificate from a trusted Certificate Authority (CA) proves you own the trademark for the logo. Some providers like Gmail require a VMC.
How to Implement BIMI
- Check DMARC compliance: Ensure your domain has DMARC at
p=quarantineorp=reject. Use a DMARC monitoring tool to verify no legitimate email fails authentication before tightening. - Create an SVG logo: Export your logo as SVG Tiny 1.2 format. Use a tool to validate it meets BIMI requirements (square, no embedded scripts, no external font references).
- Publish the BIMI DNS record: Add a TXT record to your DNS:
default._bimi.yourdomain.comwith valuev=BIMI1; l=https://assets.yourdomain.com/logo.svg; a=https://assets.yourdomain.com/certificate.pem. - Obtain a VMC: Purchase a VMC from an authorised CA such as Entrust or DigiCert. The certificate verifies your trademark ownership and enables logo display in Gmail.
- Test with BIMI validator: Use tools like BIMI Inspector or MXToolbox to verify your BIMI record is configured correctly before expecting logo display.
Related Glossary Terms
Bounce Rate
Email bounce rate is the percentage of emails that were rejected by the receiving server before reaching the recipient. It is a key indicator of list health and data quality.
Email Deliverability
Email deliverability is the ability to land in the recipient's inbox rather than the spam folder. It depends on sender reputation, authentication, list quality, and content practices.
Double Opt-In
Double opt-in (also called confirmed opt-in) is an email signup process that requires a new subscriber to confirm their email address by clicking a verification link in a confirmation email before they are added to your mailing list.
Email Alias
Alternative email addresses or subaddressing patterns that forward to a primary mailbox, affecting subscriber identity tracking and deduplication in email marketing.
Email Authentication
Email authentication (SPF, DKIM, DMARC) is a set of technical protocols that verify an email is genuinely from the domain it claims to be sent from. It prevents spoofing, phishing, and improves deliverability.
Email Bayesian Filtering
A statistical spam filtering method that uses probability calculations based on word frequency analysis to classify email messages as spam or legitimate.
Frequently Asked Questions
No. BIMI is purely a visual enhancement. It does not affect whether an email reaches the inbox or spam folder. However, because BIMI requires DMARC enforcement at quarantine or reject, implementing BIMI indirectly improves deliverability by forcing strong authentication.
No. BIMI requires DMARC policy at `p=quarantine` or `p=reject`. Domains with `p=none` or no DMARC record will not pass BIMI validation. This ensures only properly authenticated domains can display logos.
Verified Mark Certificates cost between $1,000 and $4,000 per year depending on the CA and the number of domains. The cost has been decreasing as BIMI adoption grows. Some mailbox providers display logos without a VMC, but Gmail requires it.
No. The logo must be an SVG Tiny 1.2 file, square, with no embedded scripts, no external references, and typically under 32 KB. It should be your registered trademark or brand logo. The SVG specification for BIMI is stricter than general SVG to prevent security issues.
Potentially, yes. Early studies suggest BIMI-enabled senders see 5-15% higher open rates due to increased trust and recognition. A known logo in the inbox helps your email stand out among unfamiliar senders, which can reduce the likelihood of recipients marking your email as spam.