Why does SPF alignment show as 0% on Validity, even when SPF passes?
Michael Ko
Co-founder & CEO, Suped
Published 2 Aug 2025
Updated 17 Aug 2025
7 min read
It can be perplexing to see your Sender Policy Framework (SPF) pass its authentication check, yet a tool like Validity reports 0% SPF alignment. This discrepancy often leads to confusion about your email deliverability and overall email security posture.
The key to understanding this lies in distinguishing between an SPF authentication pass and SPF alignment. While SPF might successfully verify that your sending server is authorized, alignment refers to a specific condition required by DMARC (Domain-based Message Authentication, Reporting, and Conformance).
Understanding the distinction between SPF pass and alignment
SPF is designed to prevent spammers from sending messages on behalf of your domain. It checks if the IP address of the sending server is listed in the SPF record published in your domain's DNS. This check specifically applies to the Return-Path (also known as the Mail From or Envelope From) domain, which is typically hidden from the end-user.
SPF alignment, however, is a DMARC requirement. For SPF to align, the domain found in the Return-Path header must match the organizational domain of the From: header, which is the sender's address visible to the recipient. This alignment is crucial for DMARC to validate the email's legitimacy. A comprehensive overview of these concepts is available in our simple guide to DMARC, SPF, and DKIM.
Aspect
SPF pass
SPF alignment
Verification target
Checks the sending IP against the Return-Path domain.
Compares the Return-Path domain to the From: header domain.
Impact on DMARC
Does not automatically guarantee DMARC pass without alignment.
Required for SPF-based DMARC authentication to pass.
Common scenarios
Frequently passes even when sending through third-party ESPs using their own domain for the Return-Path.
Fails when ESPs use their domain for Return-Path, preventing a match with your From: domain.
This distinction often causes confusion, especially when email service providers (ESPs) handle various aspects of email sending. For example, your email might pass SPF authentication because the ESP's sending IP is authorized by their Return-Path domain's SPF record. However, if that Return-Path domain is not your own (or a subdomain configured for alignment), then SPF alignment will fail.
Why your SPF alignment might show 0%
The primary reason for a 0% SPF alignment score, even with a passing SPF record, is typically how your email service provider manages the Return-Path domain. Many ESPs, especially those not primarily focused on advanced deliverability features, use their own domains for the Return-Path (or Envelope From) header.
This means while the email successfully authenticates against the ESP's SPF record, the domain being checked does not match your From: domain. This is a common practice with ESPs like Mailchimp, Constant Contact, SendGrid, Amazon SES, and Iterable. While this does not mean SPF is failing, it does mean SPF alignment will be 0%.
Checking your authentication results
To diagnose the alignment issue, inspect the Authentication-Results header in your email. This header will show you the results of SPF, DKIM, and DMARC checks, including whether SPF passed and if alignment was achieved.
Example Auth-results header showing SPF pass but DMARC fail (due to alignment)
Authentication-Results: mx.google.com; spf=pass (google.com: domain of bounces.example.com designates 203.0.113.1 as permitted sender) smtp.mailfrom=bounces.example.com; dmarc=fail (p=none sp=none dis=none) header.from=yourdomain.com
DMARC defines two alignment modes: relaxed and strict. In relaxed mode, SPF alignment passes if the Return-Path domain and From: domain share the same organizational domain. Strict mode requires an exact match. Most ESPs default to using their own domains for Return-Path, resulting in a 0% SPF alignment even in relaxed mode for your primary domain. You can learn more about DMARC alignment modes from Security Boulevard.
The role of DKIM in DMARC success
While SPF alignment might be 0%, it does not necessarily mean your DMARC authentication is failing. DMARC requires either SPF or DKIM (DomainKeys Identified Mail) to pass authentication and align for DMARC to succeed. This is a critical point that many overlook, as discussed in detail by Spam Resource.
Therefore, if your SPF alignment is at 0%, the validity of your DMARC will heavily depend on your DKIM setup. DKIM uses a digital signature to verify that an email was not altered in transit and that it originated from the claimed domain. For DKIM to align, the domain specified in the DKIM signature (d=) must match the organizational domain of the From: header.
Many ESPs automatically configure DKIM to align with your sending domain, even if SPF does not. If DKIM is properly configured and aligning, your DMARC will still pass, ensuring your emails are delivered and trusted by recipient servers. This is why you might see 0% SPF alignment in a report, but still achieve a high DMARC pass rate. If you are seeing SPF pass in headers but not in tools like Google Postmaster Tools, it is often due to this exact alignment nuance.
Addressing common SPF alignment challenges
To improve SPF alignment, or to ensure DMARC passes even with SPF misalignment, there are several key strategies. The most effective approach for SPF alignment is to configure your ESP to use a custom Return-Path (or Envelope From) domain that is a subdomain of your primary From: domain. This allows SPF to pass for your domain and also align, fulfilling DMARC's requirements. This is particularly relevant when SPF alignment appears inconsistent.
If your ESP doesn't support custom Return-Path domains, ensure that DKIM is correctly set up and aligning. Since DMARC only requires one of SPF or DKIM to pass and align, a strong DKIM implementation can compensate for 0% SPF alignment. Always verify your DKIM records using a reliable email deliverability testing tool to confirm proper configuration.
Regularly monitoring your DMARC reports is essential. These reports provide invaluable insight into your email authentication performance, showing you exactly whether SPF and DKIM are passing, failing, or aligning. By analyzing these reports, you can identify any authentication issues, whether it's an SPF alignment problem or a DKIM mismatch, and take corrective action. This helps maintain your sender reputation and ensures your emails reach the inbox.
Views from the trenches
Best practices
Implement DMARC with a p=none policy initially to monitor authentication results without impacting deliverability.
Ensure that your DKIM records are correctly configured and aligned with your organizational domain.
Whenever possible, use a custom Return-Path domain provided by your ESP that is a subdomain of your main domain.
Regularly review your DMARC reports to identify any persistent SPF or DKIM alignment failures.
Common pitfalls
Assuming SPF passing means DMARC will also pass without considering alignment.
Ignoring SPF alignment when DMARC reports show a high DMARC pass rate due to DKIM.
Not configuring custom Return-Path domains with your ESP, leading to generic envelope sender domains.
Failing to review Authentication-Results headers to understand the specific reason for alignment issues.
Expert tips
Even with 0% SPF alignment, if DKIM is aligned and DMARC passes, your email deliverability should not be negatively impacted.
Some ESPs, by their design, will always show 0% SPF alignment because they handle the Return-Path themselves.
Focus on overall DMARC compliance. If DMARC passes via DKIM alignment, that is sufficient for most mailbox providers.
When troubleshooting, check the envelope domain (Mail From) versus the From: header domain.
Marketer view
Marketer from Email Geeks says seeing 0% SPF alignment on Validity is possible and depends on where the email is sent from and the envelope domain used.
2024-02-02 - Email Geeks
Marketer view
Marketer from Email Geeks says many ESPs like Mailchimp and Constant Contact will always show 0% SPF alignment because they manage the sending domains themselves.
2024-02-02 - Email Geeks
Navigating SPF alignment and DMARC
Seeing 0% SPF alignment on Validity or other DMARC reporting tools, even when SPF passes, is a common scenario and not necessarily a cause for alarm. The crucial factor for DMARC is that at least one of your authentication methods—SPF or DKIM—not only passes but also aligns with your From: header domain.
If your DKIM is correctly set up and aligning, your emails will still be authenticated by DMARC, ensuring good deliverability. Understanding these nuances of email authentication, including how SPF and DKIM contribute to DMARC's overall pass or fail status, is vital for maintaining a strong sender reputation and ensuring your messages reliably reach the inbox.
Mailchimp, Constant Contact, 
SendGrid, Amazon SES, and Iterable. While this does not mean SPF is failing, it does mean SPF alignment will be 0%.
