How do Razor2 email scores impact deliverability and how can they be improved?
Matthew Whittaker
Co-founder & CTO, Suped
Published 24 Apr 2025
Updated 19 Aug 2025
8 min read
When you send emails, you want them to land in the inbox. While many factors contribute to email deliverability, one often overlooked aspect is your Razor2 score. You might see your emails pass traditional spam filters like SpamAssassin rules with flying colors, only to find their overall score drops significantly due to Razor2. This can be puzzling, especially when a score of 5.7 out of 10 might seem acceptable.
However, even a score that seems 'good enough' can have a subtle yet significant impact on where your emails land, especially with smaller or stricter mailbox providers. A drop from a near-perfect 9.9 to 5.7, for instance, often indicates a problem that can lead to reduced engagement, lower open rates, and more emails landing in the spam folder instead of the primary inbox.
This isn't just about content, but often about the underlying links and infrastructure. Understanding how Razor2 works and what triggers its detection is crucial for maintaining optimal deliverability. We'll explore its impact and practical strategies to improve your scores.
Understanding Razor2 and its role in anti-spam
Razor2 is a distributed, collaborative spam filtering network that identifies and blocks patterns of spam. It operates by generating checksums (fingerprints) of emails reported as spam by users. If a new email matches a known spam fingerprint, it's assigned a higher spam score. While it's an older system, its data feeds into broader anti-spam mechanisms, making it still relevant today, especially for content and URL reputation.
Many of its principles have been integrated into more sophisticated systems, such as Cloudmark Authority, which is a more robust commercial product. This means that while you might not directly see 'Razor2' as a primary filter, its underlying logic influences how many modern spam filters, including those used by major mailbox providers, evaluate your emails.
Unlike some filters that primarily look at headers or basic sender authentication, Razor2 often focuses on the content fingerprint of the email, including URLs within the message body. This is why an email might pass SpamAssassin checks, which have a broad range of rules, but still get flagged by Razor2 due to a specific content pattern or a blocklisted (or blacklisted) URL it identifies. It's about collective reports, not just technical misconfigurations.
This collective reporting mechanism means that if enough users mark emails containing a specific link or content structure as spam, Razor2 will learn and flag future emails with similar characteristics. This can lead to your legitimate emails being caught in the crossfire, even if your sender reputation is otherwise strong.
How Razor2 scores impact deliverability
A direct impact of a poor Razor2 score is often seen in how consistently your emails reach the inbox, particularly with internet service providers (ISPs) that might be more aggressive in their spam filtering or have fewer data points on your sending behavior. While a score of 5.7 out of 10 might still allow some emails to be delivered, it's unlikely to achieve the same inbox placement as a 9.9 score.
This subtle difference often translates into a noticeable drop in engagement metrics. If your promotional newsletters, which might contain more varied links or content, see a significant score drop, it suggests those emails are facing higher scrutiny. This isn't necessarily about email template changes but rather the reputation associated with specific elements within the email, especially URLs.
The key concept here is fingerprinting. If certain URLs or content patterns are repeatedly reported by enough users, Razor2 associates a negative fingerprint with them. Even if the content itself isn't overtly spammy, this fingerprint can trigger a lower score, pushing your emails towards the junk folder. This is particularly relevant for tracking links, affiliate links, or domains that are shared across many senders.
High Razor2 score (9.9/10)
Inbox placement: High likelihood of reaching the primary inbox across all mailbox providers.
Engagement: Maximizes open and click-through rates due to optimal visibility.
Trust: Indicates clean content and reliable sending practices, building sender trust.
Lower Razor2 score (e.g., 5.7/10)
Inbox placement: Increased risk of landing in spam, especially for less common mailbox providers.
Engagement: Lower engagement due to reduced visibility or direct spam folder placement.
Trust: Suggests potential content or link issues, which can degrade overall sender reputation.
Identifying and troubleshooting Razor2 flags
The key to improving your Razor2 score is often to isolate the problematic elements within your email. Since Razor2 primarily targets content fingerprints, and your SpamAssassin scores are clear, the issue likely lies with the links in your emails. This could include tracking links, affiliate links, or any URLs that introduce multiple layers of redirection.
To identify the specific culprit, you can run split tests. Try sending the same email content first with clean, direct links, and then with your standard tracking or affiliate links. This process of elimination will quickly show you if the issue is with your content or the links. Often, the domain used for cloaking or redirecting affiliate links is the source of the problem, as it might have been used by other senders for spammy purposes, thus acquiring a poor reputation.
Another area to investigate is the DMARC record on your tracking links. If a tracking domain has a DMARC policy set to 'reject', it indicates a strong stance against unauthorized use, which can sometimes be a signal to anti-spam systems. Ensure that all your linked domains, including tracking ones, have proper authentication set up to align with your primary sending domain.
Here's an example of how a problematic tracking URL might appear, leading to a lower Razor2 score:
Always scrutinize the entire redirect chain of your links. A clean initial link might lead to a problematic final destination or intermediate tracking domain, triggering Razor2 (or other blocklist) detection.
Strategies to improve your Razor2 scores
To prevent Razor2 from negatively impacting your deliverability, focus on maintaining a pristine reputation for all elements within your email, especially your links. Using dedicated, clean domains for both sending and tracking is a crucial step. This isolates your reputation, so if one domain gets flagged, it doesn't affect your primary sending domain.
Carefully vet any third-party tracking services or affiliate programs you use. Ensure their domains have good sending reputations and don't engage in practices that could lead to being blocklisted. If you're using your own tracking domain, set up proper DMARC, SPF, and DKIM authentication for it, just as you would for your main sending domain. This consistency builds trust with mailbox providers.
Furthermore, a proactive approach to monitoring your domain and IP reputation, including checking for any blocklist listings, can help you catch issues before they escalate. Tools that report on various spam filter scores, including those influenced by Razor2, are invaluable for this. Regularly auditing your content and link structure for anything that could be misinterpreted as spammy behavior is also important.
Remember, good deliverability is an ongoing effort that involves continuous monitoring and adaptation. By understanding the nuances of systems like Razor2, you can fine-tune your sending strategy to ensure your messages consistently reach their intended audience.
Aspect
Good practice
Common mistake
Tracking domains
Use a custom, dedicated tracking domain that aligns with your sending domain.
Using shared or generic tracking domains from ESPs, or unauthenticated domains.
Link structure
Keep redirect chains short and transparent. Ensure all redirect hops are reputable.
Employing multiple layers of redirects, especially with unknown affiliate networks.
Domain authentication
Ensure all domains (sending and tracking) have correct SPF, DKIM, and DMARC records.
Missing DMARC records on tracking domains, or misconfigured SPF/DKIM.
Only checking basic spam scores or ignoring subtle drops in deliverability.
Views from the trenches
Best practices
Regularly test your email content, including all links, using deliverability tools to catch hidden issues.
Maintain a clean sending reputation by avoiding practices that could lead to spam complaints.
Use dedicated sending and tracking domains to isolate reputation issues from each other.
Implement strong email authentication protocols like SPF, DKIM, and DMARC across all your domains.
Segment your audience and send relevant content to improve engagement metrics and reduce complaints.
Common pitfalls
Using generic or shared tracking domains that might already be associated with spammers.
Over-reliance on affiliate links with multiple redirects or complex cloaking layers.
Neglecting to monitor DMARC reports for issues specifically related to your tracking link domains.
Ignoring lower Razor2 scores, assuming deliverability will be unaffected by minor drops.
Sending to unengaged lists, which often leads to higher spam complaints and reputation damage.
Expert tips
If you are testing, isolate variables by testing content with clean links and then testing links with clean content.
DMARC reject policies on tracking domains can indicate underlying issues that contribute to blocklisting.
Implement custom tracking links for each sender or campaign to better pinpoint the source of issues.
Understand that even older blocklists like Razor2, while not as dominant, still contribute to the overall spam score.
Investigate the full path of your URLs, especially if they involve multiple redirects or third-party services.
Marketer view
Marketer from Email Geeks says they noticed a big drop in their promotional newsletter scores on Mail-Tester from 9.9/10 to 5.7/10 due to Razor2 detection, even though SpamAssassin passed. They observed this drop affects engagement with smaller inboxes.
2019-11-14 - Email Geeks
Marketer view
Marketer from Email Geeks says they would not care about Razor2 per se, but highlighted that bad URLs in content could lead to fingerprinting, which would certainly cause problems.
2019-11-14 - Email Geeks
Optimizing for inbox placement
Razor2, while not as widely discussed as some modern spam filtering technologies, still plays a role in email deliverability, particularly in identifying patterns of spam based on content and URLs. A lower score, even if seemingly marginal, can impact your email deliverability and engagement, pushing your messages into the spam folder for certain recipients.
The key to improving Razor2 scores, and ultimately your overall deliverability, lies in meticulous attention to your email's components, especially the links. By troubleshooting problematic tracking or affiliate domains, implementing robust authentication for all your linked assets, and continuously monitoring your reputation, you can significantly enhance your chances of landing in the inbox.
Proactive management of your sending infrastructure and a clear understanding of how collaborative spam filters like Razor2 operate are indispensable for any sender aiming for consistent inbox placement and strong email performance.
Cloudmark Authority, which is a more robust commercial product. This means that while you might not directly see 'Razor2' as a primary filter, its underlying logic influences how many modern spam filters, including those used by major mailbox providers, evaluate your emails.
all domains (sending and tracking) have correct SPF, DKIM, and DMARC records.
