Kit (ConvertKit) WordPress Integration: Subscribe From a Form

A Kit WordPress integration, still labeled ConvertKit in a lot of plugins, subscribes the person who submitted your form to a Kit form and can tag them. In Core Forms that is one action. It does not enroll a sequence and it does not map arbitrary custom fields.

I build Core Forms. The action on the Kit integration page is the one this guide uses. Kit’s own embed is the other way, and it is the right way if you want Kit’s form, not yours.

What you need

• A Kit account and an API key from that account.
• The numeric ID of the Kit form you want people added to.
• Tag IDs if you want tags. They are numbers, not the tag names.
• A form that already collects an email. A name is optional.

The action subscribes first and tags second. If a later step fails, a retry can continue without subscribing the same person again.

Add the action

1. In Kit, create an API key.
2. In the WordPress form, open Actions and add the ConvertKit action.
3. Paste the API key and the Kit form ID.
4. Choose the email field and, if you have one, the name field.
5. Enter any tag IDs, separated the way the field asks.
6. Save, submit the form with your own address, and check Kit before you trust it.

The confirmation on your site should say what happens next. If Kit is set to send its own confirmation, say that. The confirmation examples include a newsletter version.

What this action does not do

It does not pick a sequence. It does not write arbitrary custom fields. If the welcome series or a pile of custom properties is the point, use Kit’s form or an automation that starts from the subscriber this action creates.

A failed tag step is recorded so the retry does not repeat a subscription that already succeeded. That is the useful part. It is not a full two-way sync. Deleting someone in Kit does not delete the WordPress submission, and the other direction is just as separate.

When to use a different tool

Mailchimp, MailerLite and Brevo have their own actions if the list already lives there. The Mailchimp guide and the Brevo guide are those setups. If the list should stay in WordPress, MailerPress does not need an API key.

FAQ

Does Core Forms support Kit or ConvertKit?

Both names, one action. The product is Kit. The action is still set up with a ConvertKit API key, a form ID and tag IDs.

Can I add someone to a Kit sequence from the form?

Not with this action. Subscribe them to the Kit form, then let a Kit automation enroll the sequence. The WordPress action stops at the subscriber and the tags.

What if the email is already in Kit?

The action updates that subscriber rather than inventing a second person. Check Kit’s own confirmation rules if a new address must click a link before they are counted as subscribed.