Which mailbox providers support BIMI through Cloudmark, and how is it implemented?

Key findings

• Cloudmark's role: Cloudmark's email security gateway (CMGW) supports the validation of BIMI records, meaning it can process the necessary headers to determine if an email is BIMI compliant. It stamps headers that MUAs can then read to display the logo.
• MUA dependent: The display of the BIMI logo is ultimately controlled by the Mail User Agent (email client) used by the recipient, not solely by the mailbox provider's backend filtering system like Cloudmark. For example, Apple Mail (an MUA) can display logos regardless of the underlying ESP's specific BIMI support.
• Decoupling clients and providers: It is important to differentiate between an email client (e.g., Apple Mail app) and an email service provider (e.g., Apple iCloud). An email client might display BIMI logos by reading the headers, while an ESP ensures emails sent to its addresses have the required BIMI headers.
• BIMI requirements: For BIMI to work, the sending domain must pass DMARC authentication with a policy of at least p=quarantine or p=reject. This ensures strong domain authentication before logo display.

Key considerations

• Conditional display: Even if an email passes BIMI validation, the logo may not display if the message is classified as spam and sent to the junk folder. This is a common practice among mailbox providers.
• Mailbox provider specifics: Some providers using Cloudmark might have their own webmail interfaces that do not yet support BIMI logo display, even if the underlying mail transfer agent (MTA) validates the BIMI record. For a comprehensive list of providers, refer to the BIMI Group's official resources.
• Client-side implementation: BIMI implementation is a two-part process. Senders must publish a valid BIMI record, and email clients must be updated to read and display the logo based on that record. Our guide on BIMI implementation requirements provides more details.
• Ongoing updates: The landscape of BIMI support is continuously evolving. Mailbox providers and email clients frequently update their policies and features, impacting logo display.

Key opinions

• Ambiguity in support: Many marketers find it difficult to pinpoint exactly which mailbox providers, especially smaller or international ones, will display BIMI logos even if they use a service like Cloudmark that validates BIMI records.
• Client vs. provider confusion: There's a common misunderstanding about whether BIMI support is driven by the email service provider (like iCloud) or the email client (like Apple Mail). Marketers desire clear communication on this front.
• Desire for broader adoption: Marketers recognize the value of BIMI for brand recognition and trust, hoping for more widespread and consistent logo display across all major email platforms.
• Testing difficulties: It can be challenging for marketers to test BIMI display if they do not have access to mailboxes on less common or international providers that might use Cloudmark.

Key considerations

• UX in spam folder: Some marketers suggest that displaying BIMI logos even in the spam folder could be beneficial from a user experience (UX) perspective, helping recipients identify legitimate emails that might have been false positives.
• Investment justification: The effort and cost involved in obtaining a Verified Mark Certificate (VMC) and setting up BIMI records necessitate clear visibility into where the logo will actually appear. Learn more about the costs and steps for implementing BIMI.
• Perceived deliverability impact: While BIMI itself doesn't directly affect email deliverability, the enhanced brand trust can indirectly lead to better engagement. Flowium's blog on BIMI email authentication provides marketer insights.

Key opinions

• MUA's display role: Cloudmark stamps headers that Mail User Agents (MUAs) like Apple Mail can read to display the logo. This means the client, not necessarily the mailbox provider's webmail interface, determines display.
• Separate implementations: Proofpoint and Cloudmark may operate on separate BIMI implementations, even though Proofpoint owns Cloudmark.
• MTA vs. MUA: Cloudmark Gateway (CMGW) validates BIMI, but it's an MTA function. An MUA is still required to digest these headers and display the logo.
• Spam folder behavior: If a message passes BIMI but is flagged as spam, the logo will likely not be displayed in the spam folder, especially if it failed DMARC. This aligns with core email authentication principles.

Key considerations

• Configuration matters: It's uncertain if BIMI support via Cloudmark is an out-of-the-box setting for mailbox providers or if each customer needs to enable it.
• DMARC policy strictness: BIMI mandates a DMARC policy of at least p=quarantine. If an email fails DMARC validation, the BIMI logo will not be displayed, regardless of other factors. Our guide to DMARC implementation has more.
• Interoperability challenges: Efforts to improve BIMI interoperability among different MUAs through initiatives like IETF drafts have faced challenges, indicating a fragmented landscape.

Key findings

• Cloudmark capabilities: Cloudmark's Security Platform (e.g., version 5.8.1) includes features for processing incoming email messages that support BIMI. This involves the Mail Transfer Agent (MTA) level validation.
• MUA's responsibility: Documentation explicitly states that if BIMI is supported for an incoming email, the Mail User Agent (MUA) will be able to display an appropriate domain-based logo.
• Prerequisites: BIMI requires strong email authentication, particularly a DMARC policy of p=quarantine or p=reject, to ensure verified logo display. You can find common questions and answers about BIMI in our knowledge base.
• Apple Mail support: Apple Developer documentation provides specific guidelines for email servers to prepare for BIMI support in Apple Mail, detailing the technical steps for senders. Apple's official documentation gives an overview.

Key considerations

• Provider-specific activation: While Cloudmark facilitates BIMI, individual mailbox providers using Cloudmark still need to be on a compatible software version and actively enable the BIMI display feature within their own systems.
• Logo visibility requirements: The BIMI Group’s resources often differentiate between displaying logos in the message list versus within the opened email, explaining why some providers may not have a checkmark on specific display lists.
• No content scanner involvement: The core BIMI validation process, as defined in documentation, does not directly involve content scanners (like Vade or Cloudmark Authority), which are typically focused on spam detection.