Can link security checkers cause false no-js reports in email analytics?
Matthew Whittaker
Co-founder & CTO, Suped
Published 3 Aug 2025
Updated 18 Aug 2025
7 min read
Many email marketers and deliverability professionals closely monitor their email analytics, particularly click-through rates. These metrics are crucial for understanding campaign performance and subscriber engagement. However, a common frustration arises when tracking data appears inconsistent, with a notable number of clicks reporting as originating from environments where JavaScript (JS) is not enabled. This often leads to questions about the validity of the data and whether it indicates a real issue or something else at play.
A frequently asked question is whether email link security checkers are responsible for these false "no-JS" reports. The short answer is yes, they can indeed contribute significantly to this phenomenon. These automated systems are designed to protect recipients, but their operational methods can inadvertently skew your analytics. Understanding how these checkers function is key to interpreting your email performance data accurately and addressing any potential underlying deliverability concerns.
How security checkers operate
Email security checkers, whether part of an enterprise network's security infrastructure or a public email provider's spam filtering system, play a vital role in safeguarding users. Their primary function is to inspect incoming emails for malicious content, including phishing links, malware, and spam. To do this effectively, they often simulate a user clicking on every link within an email to analyze the destination page and its content. This proactive scanning helps prevent threats from reaching the end-user.
These automated systems don't typically load a full web browser environment when they "click" a link. Instead, they might use simplified agents or headless browsers that fetch the URL's content without executing JavaScript. This is a deliberate design choice to quickly check for immediate threats without expending resources on full page rendering or risking execution of potentially malicious scripts. Many modern email security solutions click hyperlinks in emails to perform their analysis.
Real user clicks
Clicks originate from an actual human interacting with the email. These typically load the page in a full browser environment, executing JavaScript for analytics and interactive elements.
Security scanner clicks
These clicks are initiated by automated systems to scan for threats. They often do not execute JavaScript, leading to no-JS reports in analytics.
The no-JS phenomenon in email analytics
When a security checker clicks a link without executing JavaScript, your analytics platform might register a page view or a click, but it won't be able to run any JavaScript-dependent tracking code. This means if your analytics relies on JavaScript for detailed user behavior, such as session duration, bounce rate, or specific conversions, these bot-generated interactions will appear as "no-JS" or incomplete entries. This is particularly relevant for tools like Google Analytics 4, which heavily rely on JavaScript execution.
The challenge for marketers is distinguishing between genuine user engagement and these automated scans. A high volume of immediate clicks, especially those marked as no-JS, is a strong indicator of security software activity rather than human interaction. This can artificially inflate your click numbers, making your campaign performance seem better than it is, while masking true subscriber behavior. It doesn't necessarily mean there's a problem with your email content, but rather with the interpretation of your analytics data.
It's important to differentiate between these artificial email opens and clicks and genuine user engagement. Your email service provider's (ESP) click tracking might also be affected, as their systems typically register any HTTP request to the tracking URL as a click, regardless of JS execution on the destination page. This means that while ESP data might show inflated clicks, your web analytics, which depend on JavaScript, will show fewer or no corresponding page views, leading to a discrepancy.
Mitigating false positives and improving data accuracy
To get a clearer picture of your email campaign performance, you need to implement strategies to filter out or identify bot clicks from actual user engagement. This can involve a combination of technical configurations and analytical approaches.
Strategies to prevent bot clicks
IP filtering: Identify common IP ranges associated with security scanners and filter them out of your analytics. This can be complex as these IPs change.
User-agent analysis: Look for user-agent strings that indicate automated systems rather than typical browsers. Your ESP or analytics platform may offer bot click filtering based on this.
Honeypot links: Embed invisible links in your email HTML. If these links are clicked, it's a strong sign of a bot, as a human user wouldn't see them. You can then use these clicks to flag and discard other clicks from the same source at the same time.
While honeypot links can be effective, it's worth noting that some providers, including Microsoft, have indicated concerns about using invisible links in emails. Although some organizations report no issues using them, it is important to be aware of this potential guidance from major mailbox providers. The risk is that these tactics, if abused, could be seen as deceptive and negatively impact your sender reputation, potentially leading to your email being flagged as spam or even triggering a blacklist (or blocklist) action against your domain or IP.
Additionally, analyze the timing of clicks. Bot clicks often occur almost immediately after an email is sent. While a rapid genuine click is possible, a pattern of instantaneous clicks coupled with a no-JS report strongly suggests automated activity. Comparing your email click data with your website analytics data can help identify discrepancies. If your email click rates are high but your corresponding website page views are low, it could be a sign of security scans rather than actual human engagement.
Impact on deliverability and sender reputation
It's crucial to understand that security scanners generating no-JS clicks are generally a sign that your emails are being successfully delivered to inboxes and scanned for safety. This is a normal part of the email ecosystem, not necessarily an indication of a deliverability problem. Your emails are making it through, but the interaction is by a machine, not a human. Your ESP tracking links might appear active, even if no user JavaScript is run.
While these clicks can skew your analytics, they don't inherently harm your sender reputation or deliverability, as long as the underlying email content and sending practices are legitimate. Focus on fundamental deliverability practices, such as proper authentication (DMARC, SPF, and DKIM), maintaining a clean list, and sending relevant content. These factors are far more impactful on your inbox placement than the presence of security scanner clicks. Ensuring secure HTTPS links within your emails also contributes positively to trust signals.
Views from the trenches
Best practices
Implement server-side tracking alongside client-side JavaScript analytics to capture activity from all sources, including security scanners and environments where JavaScript is disabled.
Segment your audience by behavior, separating confirmed human engagement from suspicious activity to gain a more accurate view of your campaign performance.
Regularly monitor your email engagement metrics for anomalies that could indicate bot activity, such as spikes in clicks without corresponding web traffic.
Use A/B testing with slight variations in link structure to see if different security scanners react differently, helping to isolate bot behavior.
Common pitfalls
Over-relying on client-side JavaScript for all email analytics can lead to skewed data due to security scanners not executing JavaScript.
Ignoring
no-JS
clicks as a deliverability issue instead of an analytics interpretation challenge can cause unnecessary concern.
Expert tips
Leverage log file analysis from your web server to identify and filter out clicks from known bot user agents or suspicious IP ranges.
Consider using a
Blocklist monitoring
service to proactively identify if your domains or IPs are being flagged, which could indicate a more serious underlying deliverability issue beyond bot clicks.
Marketer view
Marketer from Email Geeks says: A high amount of immediate clicks reporting as no-JS often indicates automated security clicking. It's a common observation.
2023-01-13 - Email Geeks
Expert view
Expert from Email Geeks says: Link security checkers can indeed register in analytics as browsers not supporting JavaScript, skewing click data.
2023-01-13 - Email Geeks
Navigating email analytics in a secure world
False "no-JS" reports in email analytics are a common byproduct of robust email security practices. While these automated clicks can inflate your click-through rates and complicate data interpretation, they generally do not indicate a problem with your email deliverability or content. They are, in fact, a sign that your messages are reaching their intended destinations and undergoing security screening, which is a positive indicator.
By understanding the behavior of security checkers and implementing strategies to filter out bot-generated data, you can achieve more accurate email campaign analytics. This allows you to focus on genuine subscriber engagement and optimize your email marketing efforts based on reliable performance metrics. Remember, good email hygiene and authentication remain the most critical factors for successful inbox placement, irrespective of how link checkers operate.
Microsoft, have indicated concerns about using invisible links in emails. Although some organizations report no issues using them, it is important to be aware of this potential guidance from major mailbox providers. The risk is that these tactics, if abused, could be seen as deceptive and negatively impact your sender reputation, potentially leading to your email being flagged as spam or even triggering a blacklist (or blocklist) action against your domain or IP.
