Brand Indicators for Message Identification explained

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 (MTAs) to verify the authenticity of the indicator.^{[1] [2]}

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,^[3] 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:

(The a= part is optional. When present, it defines an evidence document; the only current form of this file is called a Verified Mark Certificate (VMC), described below. When absent, the BIMI record is considered self-asserted.)

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.^[4] These factors alone will not guarantee a BIMI logo will be displayed as heuristics (like spam and spoofing) and reputation will be a key part in BIMI validity.^[5]

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.^{[6] [7]}

As of June 2023 the following e-mail services have implemented support for BIMI:

Email clients supporting BIMI! Client !! Requires VMC !! Notes

	Unknown
	Yes
	No
	Yes
	No	Domains without VMCs must be submitted and manually verified by La Poste.
	No	Only for bulk emails from high reputation domains.

History

The BIMI Working Group was founded in 2019.^[8]

Contributors

The contributors of BIMI specifications, called the BIMI Group, also called Authindicators Working Group,^{[8] [9]} include:

• Agari
• Comcast
• Google
• LinkedIn
• Return Path from Validity
• Valimail
• Verizon Media (Yahoo)

Notes and References

1. Web site: Brand Indicators for Message Identification (BIMI) Draft . 5 May 2023 . Internet Engineering Task Force . IETF Trust.
2. Web site: 2020-02-21. BIMI Up, Scotty! A look at Brand Indicators for Message Identification (BIMI) Adoption with R and the Alexa Top 1m. 2021-02-08. Security Boulevard. en-US.
3. Web site: Implementation Guide . BIMI Group . 9 February 2021.
4. Web site: Get your Verified Mark Certificate (VMC) - Google Workspace Admin Help . 2023-01-25 . support.google.com.
5. Web site: Group . BIMI . 2021-09-10 . VMCs Aren’t a Golden Ticket for BIMI Logo Display . 2023-01-25 . BIMI Group . en-US.
6. Web site: BIMI Working Group . BIMI Group . BIMI Group . 8 February 2021.
7. Web site: Google’s Gmail Is Getting Support For A New Email Feature That Allows Brands To Display Their Logos In The Avatar Slot. 2021-02-08.
8. Web site: Authindicators Working Group | LinkedIn.
9. Web site: Google Joins AuthIndicators Working Group and Commits to BIMI Pilot. BIMI. Group. July 24, 2019.