Mailchimp for WordPress includes several checks to help block spam sign-ups. Forms include a hidden honeypot field and a timestamp check. Submissions from obvious bots are rejected.

Some bots still get through. They may target your site directly, or they may use browser automation that looks more like a real visitor. If your Mailchimp audience receives spam sign-ups, use the methods below to reduce or stop them.

Enable double opt-in

Double opt-in requires every new subscriber to confirm their email address before they are added to your Mailchimp audience. Most bots cannot complete the confirmation email step. That makes double opt-in the first setting to check.

Mailchimp for WordPress double opt-in setting enabled

You can find this setting when editing your form. Scroll down to Mailchimp Settings and set Use double opt-in? to Yes.

Double opt-in should prevent most spam sign-ups. If spam continues, add a captcha or anti-bot service.

Enable Prosopo Procaptcha

Mailchimp for WordPress includes an integration with Prosopo Procaptcha. Prosopo adds privacy-friendly bot protection to your Mailchimp sign-up forms.

To enable it:

  1. Create a Prosopo account and get your site key and secret key from the Prosopo portal.
  2. In WordPress, go to Mailchimp for WP > Integrations.
  3. Open Procaptcha (by Prosopo).
  4. Enter your site key and secret key.
  5. Choose a theme and captcha type, then save the settings.

Prosopo supports light and dark themes. You can also choose frictionless protection, proof-of-work, or an image captcha. Use the frictionless option first unless you need a stronger challenge.

Use hCaptcha

The free hCaptcha plugin and service provide an integration with Mailchimp for WordPress forms.

Download the hCaptcha plugin from the WordPress.org plugin repository.

After installing the plugin, create an hCaptcha account and add your site key and secret key in the hCaptcha settings.

What to try first

Start with double opt-in. It is simple, reliable, and usually enough to stop fake subscribers from reaching your Mailchimp audience.

If spam continues, enable Prosopo Procaptcha. If you already use hCaptcha on your site, the hCaptcha plugin is also a good option.