Does a parent domain need BIMI for subdomain BIMI to work?

Summary

The provided information indicates that while BIMI settings can be inherited from a parent domain to its subdomains, it is not a mandatory requirement. A subdomain can independently implement BIMI as long as it meets the DMARC requirements (policy set to 'quarantine' or 'reject') and has a DNS record pointing to the brand's logo. The BIMI selector, although available, is not widely used, with most systems recognizing only the default selector. Therefore, the critical factor is the subdomain's DMARC compliance, enabling it to function independently of the parent domain's BIMI configuration.

Key findings

  • Independent BIMI Implementation: Subdomains can implement BIMI independently if they meet the DMARC requirements, even without the parent domain having a BIMI record.
  • DMARC Compliance is Key: DMARC compliance (policy set to 'quarantine' or 'reject') is a prerequisite for subdomains to leverage BIMI.
  • Optional Inheritance: BIMI settings can be inherited from the parent domain if the subdomain meets the DMARC requirements, but it's not a necessity.
  • Selector Usage Limited: Most systems primarily recognize the default BIMI selector.

Key considerations

  • Prioritize DMARC: Ensure the subdomain's DMARC policy is correctly configured and enforced (set to 'quarantine' or 'reject').
  • DNS Record Setup: Create a DNS record pointing to the brand's logo file for the subdomain.
  • Selector Implementation: While non-default selectors exist, using the default selector ensures broader compatibility.
  • BIMI Selector Header: BIMI-Selector header can be implemented on outbound mail.

What email marketers say
7Marketer opinions

The consensus is that a parent domain does not necessarily need a BIMI record for a subdomain to implement BIMI. The crucial factor is that the subdomain must independently meet the DMARC requirements. While BIMI inheritance from a parent domain is possible, it's not a prerequisite, and subdomains can function independently if their DMARC policy is properly configured. Selectors are available but not widely adopted. BIMI builds upon existing authentication standards.

Key opinions

  • DMARC Dependency: Subdomains must meet DMARC requirements independently to implement BIMI, regardless of the parent domain's BIMI status.
  • Independent BIMI: A subdomain can have BIMI even if the parent domain doesn't, given it adheres to DMARC.
  • Selector Use: While BIMI selectors exist, most systems currently only recognize the default selector.
  • BIMI inheritance: A subdomain can inherit from the organizational domain, but a sub-subdomain cannot inherit from a subdomain.

Key considerations

  • DMARC Configuration: Ensure the subdomain's DMARC policy is correctly configured to either 'quarantine' or 'reject' to comply with BIMI requirements.
  • BIMI Selector: Use the default BIMI selector `default._bimi.domain.com` for maximum compatibility across email systems.
  • DNS Record: A DNS record must point to your logo file.
Marketer view

Marketer from Email Geeks mentions that it is analogous to DKIM. The only non-default selector seen so far is `smile._<http://bimi.amazon.com|bimi.amazon.com>`.

August 2023 - Email Geeks
Marketer view

Email marketer from Stack Overflow answers that it is possible to have BIMI on a subdomain, even if the parent domain does not have it, as long as the subdomain meets the DMARC requirements.

February 2024 - Stack Overflow
Marketer view

Marketer from Email Geeks points out that most systems currently only recognize the default BIMI selector, `default._bimi.domain.com`.

April 2021 - Email Geeks
Marketer view

Marketer from Email Geeks shares the BIMI spec currently defines the BIMI-Selector header as one that the sender can insert on outbound mail.

January 2023 - Email Geeks
Marketer view

Marketer from Email Geeks explains that BIMI inheritance works similarly to DMARC. A subdomain can inherit from the organizational domain, but a sub-subdomain cannot inherit from a subdomain.

December 2022 - Email Geeks
Marketer view

Email marketer from Only Domains shares that BIMI allows the display of logos alongside emails in supporting inboxes. The article indicates that implementing BIMI involves creating a DNS record and ensuring DMARC compliance but doesn't explicitly say the parent domain needs BIMI for subdomains to work.

February 2025 - Only Domains
Marketer view

Email marketer from Red Sift shares that BIMI builds upon DMARC. It does not specifically state that a parent domain *needs* BIMI for a subdomain to implement it, but emphasizes the necessity of a robust DMARC policy. This suggests a subdomain could potentially implement BIMI independently if its DMARC is correctly configured.

June 2023 - Red Sift

What the experts say
4Expert opinions

The responses indicate that while BIMI can be inherited from an organizational domain to subdomains, it's not a requirement for the subdomain to function. A subdomain can independently implement BIMI if it meets DMARC requirements and sets up the necessary DNS record pointing to the logo file. Experts confirm that a parent domain does not explicitly need a BIMI record for a subdomain to successfully use BIMI.

Key opinions

  • BIMI Inheritance: BIMI settings from the organizational domain can be inherited by subdomains.
  • Independent Subdomain BIMI: A subdomain can implement BIMI independently of the parent domain.
  • DMARC Requirement: Meeting DMARC requirements is essential for a subdomain to implement BIMI.
  • DNS Setup: Setting up a DNS record pointing to the logo file is a key step in BIMI implementation for subdomains.

Key considerations

  • DMARC Compliance: Verify that the subdomain meets DMARC requirements to ensure BIMI functionality.
  • DNS Configuration: Properly configure the DNS record to point to the correct logo file location.
  • Optional Inheritance: While inheritance from the organizational domain is possible, it is not a mandatory setup.
Expert view

Expert from Email Geeks confirms that BIMI can be set up only on the subdomain if desired.

May 2023 - Email Geeks
Expert view

Expert from Word to the Wise explains that BIMI involves setting up a DNS record with a pointer to your logo file. As long as the subdomain meets the DMARC and other BIMI requirements, the parent domain does not explicitly need to have a BIMI record.

March 2024 - Word to the Wise
Expert view

Expert from Email Geeks shares that if BIMI is configured on the organizational domain, it will be inherited by any qualifying subdomain. VMCs can also be set in a similar way.

October 2022 - Email Geeks
Expert view

Expert from Spam Resource explains that subdomains can have their own BIMI records, independent of the parent domain, as long as the subdomain meets the DMARC requirements. The parent domain does not need a BIMI record for the subdomain to function correctly with BIMI.

May 2023 - Spam Resource

What the documentation says
3Technical articles

The documentation indicates that BIMI is configured at the domain level, allowing subdomains to inherit BIMI settings from the parent domain if they meet the necessary DMARC requirements. While a parent domain's BIMI configuration isn't a strict dependency for a subdomain to function with BIMI, the subdomain's DMARC policy ('quarantine' or 'reject') is crucial. The BIMI-Selector header can be inserted on outbound mail.

Key findings

  • Domain-Level Configuration: BIMI is primarily configured at the domain level.
  • DMARC Requirement: A subdomain must have a DMARC policy set to 'quarantine' or 'reject' to leverage BIMI.
  • Inheritance: Subdomains can inherit BIMI settings from the parent domain if DMARC requirements are met.
  • BIMI-Selector Header: The BIMI-Selector header can be inserted in outbound emails.

Key considerations

  • DMARC Policy: Ensure the subdomain's DMARC policy is set to 'quarantine' or 'reject'.
  • Inheritance vs. Independent Setup: Decide whether to inherit BIMI settings from the parent domain or configure BIMI independently for the subdomain.
  • BIMI-Selector Header: Explore the usage of BIMI-Selector header
Technical article

Documentation from BIMI Group explains that BIMI is configured at the domain level. If you implement BIMI on your main domain, it can be inherited by subdomains if the subdomain's DMARC policy meets the BIMI requirements. The subdomain itself doesn't need a separate BIMI record if inheriting from the parent.

August 2023 - BIMI Group
Technical article

Documentation from IETF mentions how the the BIMI-Selector header as one that the sender can insert on outbound mail.

January 2022 - datatracker.ietf.org
Technical article

Documentation from DigiCert explains that for a domain to leverage BIMI, it must have a DMARC policy set to either 'quarantine' or 'reject'. While not directly answering about parent domains, it implies a subdomain could function if *it* meets the DMARC requirement, suggesting the parent's BIMI is not a direct dependency.

August 2023 - DigiCert