Brand Indicators for Message Identification, or BIMI (/ˈbɪmi/), is a specification allowing for the display of brand logos next to authenticated e-mails.
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.[1] The BIMI DNS record is in the following format:
default._bimi TXT "v=BIMI1; l=https://example.com/logo.svg; a=https://example.com/image/certificate.pem"
(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
.
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:[8]
The BIMI Working Group was founded in 2019.[18]
The contributors of BIMI specifications, called the BIMI Group, also called Authindicators Working Group,[18][19] include:
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