Business Use Cases
Creator Newsletters
Automatically push new blog readers straight into your main Kit Form.
Drip Courses
Instantly enroll respondents into a specific Kit Sequence when they sign up for a webinar.
Dynamic Tagging
Apply specific tags (e.g., “Enterprise Lead” vs “SMB Lead”) based on the exact answers they provide in Flex Forms.
Step 1: Global Connection
Before you can push data to Kit, you must authorize Flex Forms to communicate with your account.1
Locate your Kit v4 API Key
Log into your Kit dashboard. Navigate to Settings → Developer.
Locate and copy your v4 API Key.
2
Establish the Connection
In your Flex Forms dashboard, open Integrations in the left rail (next to Global Settings).
Locate the Kit (ConvertKit) card and enter your API Key.
3
Test and Verify
Click Save & Verify. Flex Forms will ping the
https://api.kit.com/v4 endpoint to ensure the credentials are valid and that your forms/sequences can be fetched.Step 2: Form-Level Configuration
Once the global connection is established, you must activate the integration on a per-form basis. Open your specific form in the Studio and navigate to the Integrations tab.The Masterclass: Data & Tag Mapping
Unlike older CRMs that use “Lists”, Kit is primarily organized around Forms, Sequences, and Tags. Flex Forms fetches all of your Kit assets live viaremote_select so you never have to hunt for internal IDs.
remote_select
required
Target Kit Form
Loaded live from your Kit account. Contacts must be subscribed to a Form to enter your Kit ecosystem.
remote_select
Kit Sequence (Optional)
Optionally add the subscriber directly to a Kit sequence (email course) upon submission.
remote_select
Primary Tag (Optional)
Select a primary tag to be applied to every respondent who fills out this form.
string
Extra Tag IDs
Comma-separated Kit tag IDs to apply in addition to the primary tag (e.g.,
12345, 67890).select
Dynamic Tags Field
Select a block from your form (like a Checkbox Group). If the respondent selects options that exactly match the names of Tags in your Kit account, the engine will automatically apply those tags to their profile.
textarea
Custom Field Mapping
Map your form block answers to Kit Custom Fields.Syntax:
KitCustomFieldKey=flex_forms_block_name (One per line).Example Mapping:Technical Resources & Troubleshooting
Does this update existing Kit subscribers?
Does this update existing Kit subscribers?
Yes. If a respondent submits the form and their email address already exists in your Kit account, the API performs an upsert. It will append any new Tags and update their Custom Fields without duplicating the contact.
Where do I find my Kit Custom Field Keys?
Where do I find my Kit Custom Field Keys?
Inside your Kit account, navigate to a Subscriber profile to view your Custom Fields. The exact lowercase key of that field must be placed on the left side of the
= sign in the mapping text area.Official Documentation Reference
Official Documentation Reference
For advanced architectural questions regarding the v4 payload, refer to the official Kit v4 API Documentation.
Configuration Reference
Global Settings
password
required
ConvertKit API Secret
The legacy master V3 API key. (Often labeled API Secret in ConvertKit).
password
required
ConvertKit Public API Key
The public API key used for some V3 endpoint requests.
Form-Level Settings
Subscriber Data
select
required
Email Field
The primary email field for the subscriber.
select
Name Field
The subscriber’s first name field.
Field Mapping
remote_select
Available custom fields (reference)
A read-only helper to fetch live custom fields from ConvertKit for mapping reference.
Advanced State
select
default:"active"
Subscriber State
Allows you to bypass Double Opt-in by explicitly setting the creation state (e.g.,
active, inactive).