Will BIMI and stricter email practices improve deliverability and reduce blocklisting?
Matthew Whittaker
Co-founder & CTO, Suped
Published 16 Jun 2025
Updated 16 Aug 2025
6 min read
Many email senders wonder if adopting Brand Indicators for Message Identification (BIMI) and adhering to stricter email practices will automatically lead to better deliverability and fewer blocklist incidents. The short answer is yes, but the relationship is often indirect and multifaceted. While BIMI itself isn't a silver bullet, it signifies a commitment to email security that, combined with robust sending practices, significantly boosts your sender reputation and, consequently, your chances of reaching the inbox.
BIMI is a visual standard that allows your brand's logo to appear next to your authenticated emails in supported inboxes. It's a powerful tool for brand recognition and trust, but it doesn't directly impact email deliverability or prevent your emails from winding up on a blocklist. Instead, BIMI acts as a reward for strong email authentication, specifically a DMARC policy set to enforcement (quarantine or reject).
The foundational elements that truly bolster your sender reputation and deliverability are the email authentication protocols: Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting, and Conformance (DMARC). These protocols work together to verify that an email sender is authorized to send mail on behalf of a domain, combating spoofing and phishing. Properly configured authentication is crucial for email providers to trust your messages. You can learn more about DMARC, SPF, and DKIM in our comprehensive guide.
While BIMI doesn't directly improve deliverability, its indirect effects are significant. By displaying a verified logo, it increases user trust and engagement. When recipients see a recognizable logo, they are more likely to open and interact with the email, which positively influences your sender reputation. Higher engagement metrics signal to mailbox providers that your emails are valued, reducing the likelihood of them being filtered to spam. This concept is further explored in discussions around BIMI's impact on engagement.
BIMI's positive impact
Enhanced brand visibility: Displays your logo in supported inboxes like Gmail and Yahoo Mail, making your emails instantly recognizable.
Increased user trust: A verified logo signals authenticity, which can lead to higher open rates and engagement.
Indirect deliverability boost: Higher engagement rates contribute to a positive sender reputation, improving inbox placement over time.
Stricter email practices and their direct impact
Beyond authentication, adhering to strict email best practices directly impacts deliverability and helps prevent blocklisting. Major mailbox providers like Gmail and Yahoo have recently implemented stricter sender requirements, making these practices even more critical.
One of the most crucial practices is maintaining a healthy sender reputation. This involves consistently sending relevant content to engaged subscribers, keeping your bounce rates low, and minimizing spam complaints. High complaint rates or frequent bounces can quickly land your IPs or domains on a blacklist (or blocklist), severely impacting your ability to reach the inbox. Understanding how to improve your email reputation is paramount.
IP warming is another critical aspect, especially when introducing new sending IPs. Mailbox providers need to see consistent, positive sending behavior from an IP address before fully trusting it. Abruptly sending large volumes of email from a new IP can trigger spam filters and lead to immediate blocklisting. It's essential to follow a gradual warming schedule, sending to highly engaged subscribers first and slowly increasing volume and audience size.
Effective strategies
List hygiene: Regularly clean your email lists to remove inactive users, invalid addresses, and spam traps.
Content relevance: Send targeted and personalized content that resonates with your audience, reducing complaints.
Engagement monitoring: Track opens, clicks, and unsubscribes to gauge recipient interest and adjust your strategy.
Common pitfalls
Purchased lists: Using third-party or purchased lists can expose you to spam traps and inactive addresses.
Ignoring bounces: High bounce rates signal poor list quality and can harm your sender reputation.
Sudden volume spikes: Rapidly increasing sending volume, especially from new IPs, can trigger spam filters.
Navigating email blocklists (or blacklists)
Email blocklists, also known as blacklists, are databases of IP addresses or domains that have been identified as sources of spam or malicious email. Mailbox providers use these lists to filter incoming mail, preventing unwanted messages from reaching their users' inboxes. Getting on a blocklist can severely disrupt your email campaigns and harm your brand reputation. For a deeper dive, check out our guide on what an email blacklist is and how it functions.
Common reasons for landing on a blocklist include high spam complaint rates, sending to spam traps, or operating an open relay. While BIMI and authentication protocols reduce the likelihood of your domain being spoofed, they do not prevent direct listing due to poor sending practices. This is where consistent monitoring and proactive measures become essential. Knowing how your email address ends up on a blacklist is the first step to avoidance.
Addressing blocklist issues, especially with major providers like Microsoft (Hotmail, Outlook, MSN, Live), often requires persistence. They typically use internal blocklists, meaning your IP or domain might not appear on public lists. If you find your emails consistently blocked by Microsoft, reach out to their support team and be prepared to provide details about your sending practices and IP warming efforts. Sometimes, multiple attempts are necessary to get a human response.
Blocklist type
Trigger
Impact on deliverability
Public blocklists (DNSBLs)
High spam complaints, sending to spam traps, known spam sources.
Emails blocked by multiple ISPs globally. Significant deliverability issues.
Private/Internal blocklists
Specific to a single mailbox provider (e.g., Outlook.com), often based on their internal metrics.
Emails blocked only by that specific provider. Requires direct engagement for resolution.
Spam trap lists
Sending to invalid or dormant addresses repurposed as spam traps.
Can lead to immediate blocklisting and severe damage to sender reputation.
Connecting authentication, practices, and reputation
Ultimately, email deliverability and avoiding blocklists depend on a holistic approach that integrates strong authentication with impeccable sending practices. BIMI enhances brand trust and engagement, which indirectly supports deliverability by improving recipient interaction. However, it's the underlying authentication (SPF, DKIM, DMARC) and your sender behavior that form the bedrock of successful email delivery.
Mailbox providers are increasingly sophisticated in their filtering, focusing on engagement metrics, sender reputation, and adherence to authentication standards. Failing to meet these expectations can result in messages being sent to spam or outright blocked. This is why a proactive strategy, encompassing everything from proper email authentication to meticulous list management, is indispensable.
For new IP addresses, establishing a strong reputation with major mailbox providers is crucial. This means meticulously following IP warming best practices and communicating with their postmaster teams if you encounter deliverability challenges. The journey to the inbox is continuous, requiring vigilance and adaptation to evolving standards.
Views from the trenches
Best practices
Maintain rigorous list hygiene by regularly removing inactive or invalid email addresses.
Implement a gradual IP warming schedule when introducing new sending IPs to build reputation.
Ensure all email authentication protocols like SPF, DKIM, and DMARC are correctly configured.
Monitor your sender reputation continuously using tools and postmaster insights.
Provide clear and easy unsubscribe options to reduce spam complaints and improve user experience.
Common pitfalls
Sending to purchased or unverified email lists, leading to spam traps and high bounce rates.
Ignoring DMARC reports, missing critical insights into email authentication failures and abuse.
Failing to properly warm up new sending IPs, resulting in immediate blocklisting by ISPs.
Overlooking engagement metrics, which are crucial for maintaining a positive sender reputation.
Not responding persistently to ISP support inquiries when facing deliverability issues.
Expert tips
Leverage DMARC's quarantine or reject policies to prevent unauthorized use of your domain.
Segment your email lists to send highly relevant content, boosting engagement and reducing complaints.
Regularly audit your email content for spam trigger words and questionable formatting.
Proactively engage with mailbox providers like Microsoft regarding IP warm-ups.
Keep abreast of evolving email regulations and ISP requirements, like Gmail's recent changes.
Expert view
Expert from Email Geeks says more stringent best practices definitely improve deliverability and other positive outcomes. BIMI is a consequence of strong DMARC authentication, not a standalone fix. DMARC enables deliverability aligned with your sending practices.
Dec 01, 2022 - Email Geeks
Marketer view
Marketer from Email Geeks says BIMI can increase engagement and brand trust, which indirectly aids deliverability, but it does not directly prevent blocklisting.
Dec 01, 2022 - Email Geeks
A comprehensive approach to inbox success
BIMI and stricter email practices contribute to improved deliverability and reduced blocklisting, but they do so through different mechanisms. While BIMI builds brand trust and engagement (indirectly aiding deliverability), it's the rigorous implementation of SPF, DKIM, and DMARC, coupled with diligent sending practices, that directly safeguards your sender reputation and ensures your emails reach the inbox. Continuous monitoring and adaptation to evolving ISP requirements are key to long-term success in email deliverability.
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ALPHANET
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BLOCKEDSERVERS
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Validity
www.blocklist.de Fail2Ban-Reporting Service
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2stepback.dk
Fayntic Services
ORB UK
technoirc.org
TechTheft
Displays your logo in supported inboxes like Gmail and Yahoo Mail, making your emails instantly recognizable.
and Yahoo have recently implemented stricter sender requirements, making these practices even more critical.
Specific to a single mailbox provider (e.g., Outlook.com), often based on their internal metrics.
