Brand Indicators for Message Identification


Brand Indicators for Message Identification, or BIMI, is a specification allowing for the display of brand logos next to authenticated e-mails.

Design

There are two parts to BIMI: a method for domain owners to publish the location of their indicators, and a means for mail transfer agents to verify the authenticity of the indicator.
To implement BIMI, companies need a valid DMARC DNS record with a policy of either quarantine or reject, an exact square logo for the brand in SVG Tiny P/S format, and a DNS TXT record for the domain indicating the URI location of the SVG file. The only supported transport for the SVG URI is HTTPS. The BIMI DNS record is in the following format:
Additionally, services such as Gmail require that a VMC be acquired and presented with the TXT record in order for the brand logo to be displayed in the inbox. These factors alone will not guarantee a BIMI logo will be displayed as heuristics and reputation will be a key part in BIMI validity.
To query the value of the default._bimi TXT record for a given domain, one can use the dig command-line tool. For example, the following command will query the TXT record for the example.com domain: dig +short default._bimi.example.com TXT.

Implementations

A working group of several companies named "BIMI Group" has formed to develop and support standardization of BIMI in IETF.
As of June 2023 the following e-mail services have implemented support for BIMI:
ClientRequires VMCNotes
AOL MailUnknown-
Apple MailYes-
FastmailNo-
GmailYes-
La PosteNoDomains without VMCs must be submitted and manually verified by La Poste.
Yahoo! MailNoOnly for bulk messages from high-reputation domains
HalonYes-

History

The BIMI Working Group was founded in 2019
and the first Internet Draft was published in October 2021.

Benefits

BIMI provides several advantages for organizations implementing email authentication:
  1. Increased Trust and Brand Recognition – BIMI displays verified brand logos directly in recipients' inboxes, building trust and visibility before an email is opened.
  2. Higher Engagement and Deliverability – Recognizable brand logos help improve open rates and click-through rates, while BIMI requires a strong DMARC policy that enhances email authentication and deliverability.
  3. Protection Against Phishing and Spoofing – BIMI enforces domain authentication and verified mark certificates, helping to prevent misuse of brand identity in fraudulent emails.

    Contributors

The contributors of BIMI specifications, called the BIMI Group, also called Authindicators Working Group, include: