How to effectively use KBXSCORE for deliverability testing?
Michael Ko
Co-founder & CEO, Suped
Published 28 Jun 2025
Updated 16 Aug 2025
5 min read
Email deliverability can be a complex challenge, with many factors influencing whether your messages reach the inbox or end up in the spam folder. One crucial step in maintaining healthy email deliverability is proactive testing. While many tools offer comprehensive suites, sometimes a quick, focused check is all you need to identify potential issues before a major send.
This is where KBXSCORE comes in. It's designed to provide a rapid assessment of your email's health, focusing on key technical configurations and common spam triggers. By understanding and effectively utilizing its WARN, PASS, or FAIL scoring system, you can quickly pinpoint areas needing attention, safeguarding your sender reputation and maximizing your inbox placement rates.
Think of it as a diagnostic scan that highlights immediate concerns, allowing you to address them before they escalate into larger deliverability problems. Regularly incorporating this simple tool into your email sending workflow can make a significant difference in your overall email program's success.
What KBXSCORE measures
KBXSCORE evaluates your email's technical foundation and content against a set of criteria commonly used by mailbox providers and spam filters. Its core function is to assess the overall health of your email and assign a clear, actionable score.
This scoring system is straightforward. A PASS indicates that your email has met the expected standards for deliverability, while a WARN suggests an area that needs attention, though it might not immediately block delivery. A FAIL points to a critical issue that will likely lead to messages being rejected or sent to spam.
The tool analyzes various components of your email, from authentication protocols to content flags. It's important to remember that this tool provides a snapshot, offering a quick diagnostic rather than an exhaustive inbox placement test across all providers or full-scale rendering checks. For those, you would typically need more comprehensive email deliverability testing tools.
Leveraging KBXSCORE for pre-send checks
To get started with KBXSCORE, you simply send an email to the unique address provided by the tool. This test email should ideally be representative of the actual emails you plan to send, including your sender identity, content, and any links. The goal is to simulate a real-world email as closely as possible.
Send your test email: From your sending platform or client, compose and send your email to the address provided by the tool.
Review the report: KBXSCORE will quickly process your email and generate a detailed report showing your score and specific checks.
I often use it for quick checks on new email templates or before a large campaign to ensure all authentication records, like SPF, DKIM, and DMARC, are correctly configured and passing. It's an excellent way to catch common errors that could lead to your emails being filtered or rejected by mailbox providers.
Actionable insights from your KBXSCORE report
Once you receive your KBXSCORE report, the real work begins, especially if you see any WARN or FAIL statuses. The report breaks down various checks, providing insights into specific issues. For example, if your SPF record fails, the tool will highlight this, prompting you to investigate your DNS records. Understanding why your emails fail is the first step towards a solution.
For content-related warnings, I often refer to general email deliverability best practices. It's about finding a balance between compelling marketing language and avoiding anything that might trigger a spam filter. If a warning persists after adjustments, it's worth digging deeper into the specific content elements highlighted by the tool.
Finally, if you find your IP or domain on a blacklist (or blocklist), it's important to understand how email blacklists (or blocklists) work and address the root cause of the listing. This often involves reviewing your sending practices, list hygiene, and potentially requesting delisting from the specific blocklist.
Integrating KBXSCORE into a broader deliverability strategy
While KBXSCORE is a powerful diagnostic tool, it's most effective when used as part of a comprehensive email deliverability strategy. It provides a quick health check, but a deeper dive into your sender reputation and overall program performance is always beneficial.
Consider complementing KBXSCORE with ongoing deliverability monitoring, seed list testing, and regular analysis of your email engagement metrics. This holistic approach ensures that you not only identify immediate issues but also maintain long-term inbox success. For a broader perspective, you might explore popular email deliverability testing tools and their features to find a solution that fits all your needs.
Regular testing and proactive management are key to consistent inbox placement. KBXSCORE streamlines the initial diagnostic process, allowing you to quickly react to potential problems and keep your email program running smoothly.
Views from the trenches
Best practices
Always re-test your email with KBXSCORE after making any changes to your email authentication records or content to confirm the fixes. This ensures that your adjustments have the desired positive impact on your deliverability score.
Integrate KBXSCORE into your pre-send checklist for every new campaign or significant email update. This proactive step can prevent major deliverability issues and protect your sender reputation.
Use the detailed insights provided by KBXSCORE to educate your marketing and content teams on common deliverability pitfalls. This can foster a shared understanding of email health.
Common pitfalls
Relying solely on KBXSCORE for all deliverability testing. While excellent for quick checks, it doesn't replace comprehensive inbox placement tests across various mailbox providers or detailed rendering previews.
Ignoring 'WARN' results because they aren't 'FAIL'. Warnings indicate potential issues that could escalate or impact deliverability with specific mailbox providers over time. They should be addressed.
Overlooking the impact of content. Even with perfect authentication, spammy content can trigger filters. Use KBXSCORE's content analysis to refine your messaging and avoid hidden pitfalls.
Expert tips
Pay close attention to the specific SpamAssassin rules triggered in your KBXSCORE report. These often provide granular details about content or formatting issues that might be red flags for spam filters.
If you receive an SPF failure from KBXSCORE, double-check your SPF record for any syntax errors or missing includes. Sometimes, complex SPF records with macros can be misread by standard checkers.
Remember that blocklist (or blacklist) checks are just one piece of the puzzle. While KBXSCORE covers some, a comprehensive blocklist monitoring solution is crucial for ongoing reputation management.
Expert view
Expert from Email Geeks says they found the tool awesome and especially useful for learning that SpamAssassin does not check against SPF macros, which can lead to false-positive results.
2022-01-06 - Email Geeks
Expert view
Expert from Email Geeks mentioned that some blocklist checks in the tool might be too aggressive, noting that SORBS lists are complex. It's often sufficient to check only a few key SORBS zones like dnsbl.sorbs.net, spam.dnsbl.sorbs.net, and recent.spam.dnsbl.sorbs.net for most purposes.
2022-01-06 - Email Geeks
Boosting your email deliverability with KBXSCORE
KBXSCORE serves as a valuable, free resource for anyone involved in email sending. Its straightforward approach to identifying critical deliverability factors allows for quick diagnosis and enables you to address issues proactively. By integrating it into your regular workflow, you can maintain a healthier email sending reputation and ensure your messages consistently reach their intended recipients.
