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ConvertKit Integration

Subscribe the form submitter to a ConvertKit form or sequence, with optional tag assignment.

Action type: convertkit Class: Core_Forms\Actions\ConvertKit Source: src/actions/class-convertkit.php

Setup

  1. Log in to ConvertKit and go to Settings > Advanced > API.
  2. Copy your API Key.
  3. Find the Form ID of the ConvertKit form you want to subscribe to (visible in the form URL or settings).
  4. In WordPress, edit your form > Actions tab > Add Action > Add to ConvertKit.
  5. Enter the API Key and ConvertKit Form ID.

Settings Reference

Setting Required Default Description
API Key Yes -- ConvertKit API key
ConvertKit Form ID Yes -- Numeric ID of the ConvertKit form to subscribe to
Email Field No email Form field name containing the email address
Name Field No name Form field name containing the subscriber's name
Tag IDs No -- Comma-separated tag IDs to apply to the subscriber

Tags

To apply tags, enter their numeric IDs separated by commas:

123,456,789

Find tag IDs in ConvertKit under Subscribers > Tags. Each tag subscription is sent as a separate API call to tags/{tag_id}/subscribe.

How It Works

  1. Validates the API key, form ID, and that the email field contains a valid address.
  2. Builds a subscriber payload with api_key, email, and first_name.
  3. If tag IDs are configured, subscribes the email to each tag individually via POST /v3/tags/{id}/subscribe.
  4. Subscribes the email to the ConvertKit form via POST /v3/forms/{id}/subscribe.
  5. All requests are sent as JSON to https://api.convertkit.com/v3/.
  6. The request times out after 15 seconds.
  7. Returns true if the form subscription succeeds (status below 400).

Example

Form with name and email fields, subscribing to ConvertKit form 12345 with tags for "website-lead" (tag 100) and "newsletter" (tag 200):

  • API Key: your_api_key
  • ConvertKit Form ID: 12345
  • Email Field: email
  • Name Field: name
  • Tag IDs: 100,200

Troubleshooting

  • Subscriber not appearing: Verify the API key is correct and the ConvertKit form ID exists. Check the form is not archived.
  • Tags not applied: Ensure tag IDs are numeric and exist in your ConvertKit account.
  • Invalid email: The action requires a valid email address. If the email field is empty or invalid, the action silently skips.
  • Name field: Only the full value of the name field is sent as first_name. ConvertKit does not split first/last names.