Kit (ConvertKit)

This connector uses the Kit v4 API (Kit was renamed from ConvertKit in 2024 — the API still works at api.convertkit.com under v4).

Setup:

1. Sign in to https://app.kit.com → Advanced Settings → API → Show v4 API key.
2. Copy the v4 API key. Set CONVERTKIT_API_KEY.
3. (Optional, only for older v3 endpoints not used here): the v3 API uses an api_secret — not needed for this connector.

Authentication: Authorization: Bearer ${CONVERTKIT_API_KEY}. The adapter handles this via BEARER_TOKEN.

Subscriber model: every email is a 'subscriber'. State machine: active, inactive (manually paused), bounced, complained, cancelled. New subscribers default to active. Adding to a sequence does NOT create an active subscriber automatically — they must be active first.

Tags vs Forms vs Sequences:

• Forms: capture points (signup widgets, landing pages). When a subscriber fills a form, they're added to the form's list AND tagged with any default tags the form applies.
• Tags: free-form labels. The primary segmentation primitive. A subscriber can have unlimited tags.
• Sequences: timed email courses (used to be 'autoresponder courses'). You subscribe a contact to a sequence and they receive its emails on a schedule.
• Broadcasts: one-time emails to a subset (by tags/forms/sequences). The newsletter primitive.

Custom fields are at the account level — define them in the UI, then set values per subscriber via fields object in create/update.

Pagination: cursor-based. List responses include pagination: {has_previous_page, has_next_page, start_cursor, end_cursor, per_page}. Pass after=$end_cursor (or before=$start_cursor) on the next call. Default per_page=500, max 5000 for some endpoints.

Rate limits: 600 requests per minute per API key. On 429, back off — X-RateLimit-Reset header tells you when.

Webhooks out of scope (Kit supports them, configured in UI to point at your hosted endpoint).

Out of scope here: writing automation rules, landing-page builder, commerce / digital products, deliverability headers config.