Connect Ninja Forms to Kit (formerly ConvertKit)
Connect Ninja Forms to Kit, the email platform formerly known as ConvertKit, and every form submission becomes a subscriber in the Kit form you choose. The free ClickSyncr for Kit plugin adds a ClickSyncr Kit action in the Ninja Forms builder: connect your v4 API key once, pick a Kit form, map your fields, save. So there is no code, and it takes about two minutes per form.
Before you begin
You need three things: the ClickSyncr for Kit plugin activated, Ninja Forms active, and a Kit account (free accounts work, including accounts from the ConvertKit era) with permission to create a v4 API key. You store the key once, and every supported builder on the site then shares it.
Get your Kit v4 API key
- Log in to Kit and open your account settings, then go to the Developer (API Keys) section.
- Create a v4 API key. Accounts from the ConvertKit era work the same way.
- Copy it and paste it into any ClickSyncr Kit panel. One key serves the whole site, and free Kit accounts work.
Treat the key like a password. Anyone holding it can read and modify your Kit subscribers.
Ninja Forms setup, step by step
- Open the form and add the ClickSyncr Kit action. From Ninja Forms → Dashboard, edit a form, open the Emails & Actions drawer and add ClickSyncr Kit.
- Paste your Kit v4 API key and connect. Also, you store the key once, and every other form and builder reuses it across every ClickSyncr Kit surface on the site, so other forms and builders reuse the same connection.
- Choose the Kit form. In fact, the dropdown lists every form in your Kit account, so each WordPress form can feed a different Kit form.
- Map your form fields. Then Email is the required mapping; first name and every custom field in your Kit account load automatically once the key connects.
- Optional: set a consent field. Also, choose a checkbox, acceptance or radio field to drive opt-in. Ticked adds the subscriber to the Kit form you chose; unticked saves them in Kit as a subscriber only, without joining the form, so no form emails or automations fire.
- Publish the form. In addition, the action now runs on every submission.
Email, first name, and custom fields
Kit identifies subscribers by email, so Email is the one required mapping. First name has its own field, and every custom field in your Kit account loads automatically once the key connects, ready to receive any other form input. Also, ClickSyncr simply skips an unmapped field and never overwrites existing subscriber data with a blank value. Because subscribers are matched by email, a repeat submission updates the existing subscriber instead of creating a duplicate.
Double opt-in, the Kit way
Kit handles confirmation at the form level: each Kit form carries its own incentive email and double opt-in settings inside Kit. ClickSyncr subscribes the visitor to the Kit form you chose, and your form’s own settings decide whether a confirmation email goes out first. That means your opt-in behaviour stays exactly where Kit users expect to manage it.
Verify the sync
First, submit the form on the front end (not the admin preview) with a test address you can recognise, filling every mapped field. Then, in Kit, open Subscribers and confirm the subscriber exists with the mapped values, and check the Kit form’s own reporting for the new entry. In short, that one minute catches almost every configuration mistake.
Troubleshooting
| Symptom | Cause and fix |
|---|---|
| The Kit form dropdown is empty | The key is missing or mistyped, or it is not a v4 key. Create a v4 API key in Kit’s Developer section, re-paste it and reconnect. |
| Submissions do not appear in Kit | Nine times out of ten the Email field is not mapped. It is the one required mapping. Fix it, then submit a fresh test. |
| A new Kit form or custom field is not listed | The catalog is cached briefly. Use the refresh control in the Ninja Forms settings. |
| The subscriber syncs but a field is empty | Either that field is unmapped, or it was blank on the submission. ClickSyncr skips empty values, so they never wipe existing Kit data. |
| The subscriber shows as unconfirmed in Kit | Your Kit form has double opt-in enabled, so Kit sent a confirmation email first. The Kit form’s own settings control that, not the plugin. |
Does the action work with the free Ninja Forms?
Yes. The ClickSyncr Kit action appears in the free Ninja Forms builder; no paid extension is needed.
Can I use the action on only some forms?
Yes. The action syncs only the forms you add it to, each with its own Kit form and mapping.
Other form builders
ClickSyncr for Kit also connects Contact Form 7 · WPForms · Gravity Forms · Fluent Forms · Formidable Forms · Forminator. Overview, features and pricing: Kit integration for WordPress. Browse all ClickSyncr integrations.
“Kit” and “ConvertKit” are trademarks of Kit, Inc. ClickSyncr for Kit is an independent integration and is not affiliated with, endorsed by, or sponsored by Kit, Inc.