Stop Paying Klaviyo for Bot Subscribers

If you use Klaviyo, Mailchimp, or any email marketing platform with usage-based pricing, form spam might be silently inflating your bill every month.

The Hidden Cost

Here’s how it works: a bot submits your contact form with a fake email address. If your store is set up to add contact form submissions to a mailing list (a common setup), that fake address becomes a subscriber. You’re now paying to store and send emails to an address that will never open them.

At scale, this adds up fast. We’ve seen stores with 30-40% of their “subscribers” coming from bot submissions. On Klaviyo’s pricing tiers, that can mean hundreds of dollars per year in wasted spend.

The Deliverability Problem

It gets worse. Sending emails to fake or inactive addresses hurts your sender reputation. Email providers track bounce rates, and if yours climbs too high, your legitimate marketing emails start landing in spam folders too. You’re not just paying for bots. They’re actively undermining your ability to reach real customers.

How to Identify the Problem

Check your subscriber list for these red flags:

• Email addresses with random strings (xk4j2@example.com)
• Clusters of signups from the same time window
• Subscribers with zero opens across multiple campaigns
• Addresses from disposable email domains

If you’re seeing these patterns, form spam is likely the source.

Prevention Over Cleanup

Cleaning your list after the fact is tedious and doesn’t stop the flow. The better approach is to prevent fake submissions from reaching your marketing platform in the first place. By filtering spam at the form level, before it enters your pipeline, you keep your lists clean and your costs under control.

The Math

If FormSentry blocks even 50 bot submissions per month that would have become fake subscribers, and your email platform charges $0.01-$0.02 per subscriber per month, the app pays for itself many times over. And that’s before counting the deliverability improvements.