What is prefetching and why does it cause false clicks?
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You check your dashboard five minutes after sending and see clicks rolling in. But your email just went out to 8,000 subscribers. That's prefetching, not real readers.
Prefetching happens when something other than a human follows the links in your email. There are two main sources:
Security gateway scanners. Corporate email security tools follow every link in incoming messages to check for malware and phishing. They do this immediately after delivery, before any human has opened the email. If your subscribers work at large companies using these tools, you'll see click events fire within seconds of sending.
Link preview services. Some email clients and messaging apps pre-load link content to display previews. This triggers a request to your tracking redirect, which your ESP counts as a click.
Both behaviors look identical to a legitimate click from your ESP's perspective. The request hits the tracking server, a click event gets logged, and your CTR goes up.
Why this matters: if your CTR looks great but conversions in your analytics tool are nowhere close, prefetching is a likely cause. Some ESPs have bot filtering that catches known scanner signatures. Others don't. Check your ESP's documentation on bot click filtering, and look at whether clicks are clustering in the first 1-3 minutes after send. That's a strong signal you're seeing scanners, not subscribers.
For more context on how bots inflate click counts more broadly, and how to tell them apart from real engagement, that's worth a read alongside this.
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