Has anyone here used a CAPTCHA alternative for Knack? The issue is that for most you need a TXT file on the DNS and Knack uses its own servers, so it won’t work
Hi Bradley, if you’re dealing with bot spam on public Knack forms, here’s a simple alternative that requires no external integrations:
Add a custom validation question to your form that only accepts a specific answer. For example:
Then set a field-level validation rule that only allows the correct value (in this case, “3”).
Why this works: Most spam bots auto-fill form fields with random data and can’t parse natural language or perform simple calculations. This stops the majority of generic bot submissions.
Limitations: This won’t stop sophisticated AI-powered bots, but it’s effective against the common automated spam most public forms receive. If you need stronger protection, a CAPTCHA solution outside of Knack would be the next step.
It’s a quick, no-cost solution worth trying before investing in more complex alternatives.
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