Kit (ConvertKit) API + MCP (2026): v4 + Community MCP Coverage

Kit’s API v4 is the modern REST API for programmatic access to subscribers, tags, forms, sequences, broadcasts, and Kit Commerce. Simple API key authentication, JSON payloads, generous rate limits (600 requests per minute per API key), well-documented webhook subscriptions. What Kit does NOT ship in 2026: an official Model Context Protocol server. AI-agent access comes from community MCP wrappers rather than first-party — unusual for a modern ESP but consistent with Kit’s small engineering team and creator-first positioning.

At a glance

MCP integration in 2026

Model Context Protocol is the emerging standard for connecting LLM agents to external tools. Kit has not yet shipped a first-party MCP server, which is notable given the creator community’s early enthusiasm for AI workflows. Community wrappers fill the gap for now.

Available MCP servers for Kit

API v4 essentials

Authentication methods

API key (X-Kit-Api-Key header)

Simplest and most common for internal use. Generate an API key in your Kit account under Account › Settings › Advanced › API. Send it in the request header:

X-Kit-Api-Key: YOUR_API_KEY
Content-Type: application/json
Accept: application/json

API keys are account-scoped and inherit full account permissions. No granular scopes — a token can do anything the account allows. Rotate keys promptly if compromised.

OAuth 2.0 (for public apps)

Required for third-party apps published in the Kit integration marketplace. Standard three-leg authorization code flow. Register your app in the Kit Developer Portal. Access tokens have long lifetimes; no refresh required for most use cases.

Rate limits

The 600 req/min per API key ceiling is generous for typical creator workflows. Only large-scale migrations (100K+ subscribers moving in a batch) push near the limit — use batch endpoints for bulk operations.

Official SDKs

Kit’s official SDK footprint is thin (2 official). For Python, Ruby, .NET, and other languages, community wrappers exist but quality varies. Direct API calls with your language’s HTTP client are often safer than an unmaintained community SDK.

Endpoints reference

Code examples

Node.js: add subscriber and tag

const axios = require('axios');

const API_KEY = 'YOUR_API_KEY';
const BASE_URL = 'https://api.kit.com/v4';

async function subscribeWithTag(email, tagId) {
  // 1. Create subscriber
  const created = await axios.post(
    `${BASE_URL}/subscribers`,
    {
      email_address: email,
      first_name: 'Alaa',
      state: 'active'
    },
    { headers: { 'X-Kit-Api-Key': API_KEY } }
  );

  // 2. Add tag
  await axios.post(
    `${BASE_URL}/tags/${tagId}/subscribers`,
    { email_address: email },
    { headers: { 'X-Kit-Api-Key': API_KEY } }
  );

  console.log(`Subscribed and tagged: ${created.data.subscriber.id}`);
}

subscribeWithTag('user@example.com', 'YOUR_TAG_ID');

Common gotchas

Deprecations and changelog

• API v4 is current. Modern REST API with cleaner authentication and better documentation.
• API v3 deprecated. Legacy integrations should migrate to v4 promptly.
• No official MCP server as of 2026. Community MCPs (aplaceforallmystuff/mcp-kit, mcpmarket) fill the gap.
• ConvertKit renamed to Kit in 2024. API and product names transitioning; some docs still reference “ConvertKit”.
• Kit Commerce API endpoints matured in 2024-2025 for programmatic creator commerce integration.

Frequently asked questions