Kit (formerly ConvertKit)

Email marketing platform for creators and newsletter businesses.

Capabilities

Integration	Available	Notes
API	✓	REST API for subscribers, forms, sequences
MCP	-	Not available
CLI	-	Not available
SDK	✓	JavaScript, Ruby gems available

Authentication

• Type: API Key or API Secret
• Parameter: api_key={key} or api_secret={secret} in query/body
• Get key: Settings > Advanced in Kit dashboard

Common Agent Operations

List subscribers

GET https://api.convertkit.com/v3/subscribers?api_secret={api_secret}&page=1

Get subscriber

GET https://api.convertkit.com/v3/subscribers/{subscriber_id}?api_secret={api_secret}

Add subscriber to form

POST https://api.convertkit.com/v3/forms/{form_id}/subscribe

{
  "api_key": "{api_key}",
  "email": "user@example.com",
  "first_name": "John",
  "fields": {
    "company": "Example Inc"
  }
}

Add subscriber to sequence

POST https://api.convertkit.com/v3/sequences/{sequence_id}/subscribe

{
  "api_key": "{api_key}",
  "email": "user@example.com"
}

Tag subscriber

POST https://api.convertkit.com/v3/tags/{tag_id}/subscribe

{
  "api_key": "{api_key}",
  "email": "user@example.com"
}

Remove tag from subscriber

DELETE https://api.convertkit.com/v3/subscribers/{subscriber_id}/tags/{tag_id}?api_secret={api_secret}

Update subscriber

PUT https://api.convertkit.com/v3/subscribers/{subscriber_id}

{
  "api_secret": "{api_secret}",
  "first_name": "Jane",
  "fields": {
    "plan": "pro"
  }
}

Unsubscribe

PUT https://api.convertkit.com/v3/unsubscribe

{
  "api_secret": "{api_secret}",
  "email": "user@example.com"
}

List forms

GET https://api.convertkit.com/v3/forms?api_key={api_key}

List sequences

GET https://api.convertkit.com/v3/sequences?api_key={api_key}

List tags

GET https://api.convertkit.com/v3/tags?api_key={api_key}

Create broadcast

POST https://api.convertkit.com/v3/broadcasts

{
  "api_secret": "{api_secret}",
  "subject": "Newsletter Subject",
  "content": "<p>Email content here</p>",
  "email_layout_template": "default"
}

Key Concepts

• Subscribers - Email contacts
• Forms - Signup forms
• Sequences - Automated email series
• Tags - Subscriber labels
• Broadcasts - One-time sends
• Custom Fields - Subscriber attributes

Subscriber States

• active - Can receive emails
• unsubscribed - Opted out
• bounced - Email bounced
• complained - Marked as spam
• inactive - Cold subscriber

When to Use

• Creator/newsletter businesses
• Simple email automation
• Form-based list building
• Tagging and segmentation
• Course email sequences

Rate Limits

• 120 requests per minute
• Batch endpoints available

Relevant Skills

• email-sequence
• content-strategy