Kit website screenshot

Kit

Kit (formerly ConvertKit) is an email marketing and creator platform. The Kit API V4 exposes subscribers, broadcasts, sequences, tags, custom fields, forms, purchases, and webhooks. V3 is deprecated.

Kit publishes 3 APIs on the APIs.io network: Account API, Broadcasts API, and Subscribers API. Tagged areas include Email Marketing, Creator Economy, Newsletters, Automation, and Subscribers.

The Kit catalog on APIs.io includes 1 event-driven AsyncAPI specification and 1 Spectral governance ruleset.

Kit’s developer surface includes authentication, developer portal, signup flow, pricing, engineering blog, and 10 more developer resources.

🌐 Visit website 📡 Source on GitHub
48.8/100 developing ▬ flat Agent 36/100 agent ready Full breakdown ↓
scored 2026-07-28 · rubric v0.6
AccessPaidSelf serve
4 APIs
Email MarketingCreator EconomyNewslettersAutomationSubscribers

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-28 · rubric v0.6
Composite quality — 48.8/100 · developing
Contract Quality 18.0 / 25
Developer Ergonomics 4.3 / 20
Commercial Clarity 11.6 / 20
Operational Transparency 3.4 / 13
Governance 5.0 / 12
Discoverability 6.5 / 10
Agent readiness — 36/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 6 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/kit: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 4

Individual APIs this provider publishes, each with its own machine-readable definition.

Kit API V3 (Deprecated)

The legacy ConvertKit V3 API is deprecated and slated for discontinuation; new integrations should target V4.

Kit Account API

Account, creator profile, and account-level statistics

Kit Broadcasts API

One-off email broadcasts

Kit Subscribers API

Subscriber records and lifecycle

Open Collections 1

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Kit API V4

OPEN COLLECTION

Pricing Plans 1

Published pricing tiers and plan structures.

Kit Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Kit Rate Limits

1 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Kit Finops

FINOPS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Kit Webhooks

AsyncAPI 2.6 description of the Kit (formerly ConvertKit) webhook surface. Kit delivers webhook notifications via HTTP `POST` requests with a JSON body to a `target_url` registe...

ASYNCAPI

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Kit API Rules

7 rules · 1 errors 6 warnings

SPECTRAL

Security Posture 4

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Kit Authentication

apiKey/oauth2 · 2 schemes

SECURITY

Kit Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Kit Vulnerability Disclosure

Bugcrowd

SECURITY

Kit Trust Center

SOC 2, ISO 27001, ISO 27018, GDPR

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Kit Scopes

1 scope · authorizationCode

1 scopes

SCOPES

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Kit Agentic Access

9 operations · 3 acting

9 operations · 3 acting

AGENTIC

Resources

Get Started 2

Portal, sign-up, and the first successful call

Portal
Portal
 Signup
Signup

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization

Access & Security 5

Authentication, authorization, and security posture

TrustCenter
TrustCenter
 VulnerabilityDisclosure
VulnerabilityDisclosure
 DomainSecurity
DomainSecurity
 Authentication
Authentication
 OAuthScopes
OAuthScopes

Operate 1

Status, limits, changes, and where to get help

RateLimits
RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

Pricing
Pricing
 Plans
Plans
 FinOps
FinOps

Company 2

The organization behind the API

Website
Website
 Blog
Blog

Source (apis.yml)

apis.yml Raw ↑ 
aid: kit
url: https://raw.githubusercontent.com/api-evangelist/kit/refs/heads/main/apis.yml
name: Kit
kind: company
description: Kit (formerly ConvertKit) is an email marketing and creator platform. The Kit API V4 exposes subscribers, broadcasts,
  sequences, tags, custom fields, forms, purchases, and webhooks. V3 is deprecated.
accessModel:
  pricing: paid
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Paid · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/kit.png
tags:
- Email Marketing
- Creator Economy
- Newsletters
- Automation
- Subscribers
created: '2026-05-08'
modified: '2026-05-30'
specificationVersion: '0.19'
apis:
- aid: kit:kit-api-v3
  name: Kit API V3 (Deprecated)
  humanURL: https://developers.kit.com/v3/api-reference
  baseURL: https://api.convertkit.com/v3
  tags:
  - Email Marketing
  - Subscribers
  - Deprecated
  description: The legacy ConvertKit V3 API is deprecated and slated for discontinuation; new integrations should target V4.
  properties:
  - type: Documentation
    url: https://developers.kit.com/v3/api-reference
  - type: Deprecation
    url: https://developers.kit.com/v4/api-reference/v3-to-v4-upgrade-guide
- aid: kit:kit-account-api
  name: Kit Account API
  description: Account, creator profile, and account-level statistics
  humanURL: https://developers.kit.com/v4/api-reference
  baseURL: https://api.kit.com/v4
  tags:
  - Account
  properties:
  - type: OpenAPI
    url: openapi/kit-account-api-openapi.yml
  - type: Documentation
    url: https://developers.kit.com/v4/api-reference
  - type: Authentication
    url: https://developers.kit.com/v4/api-reference/authentication
  - type: Webhooks
    url: https://developers.kit.com/v4/api-reference/webhooks
  - type: Migration
    url: https://developers.kit.com/v4/api-reference/v3-to-v4-upgrade-guide
  - type: AsyncAPI
    url: asyncapi/kit-webhooks-asyncapi.yml
- aid: kit:kit-broadcasts-api
  name: Kit Broadcasts API
  description: One-off email broadcasts
  humanURL: https://developers.kit.com/v4/api-reference
  baseURL: https://api.kit.com/v4
  tags:
  - Broadcasts
  properties:
  - type: OpenAPI
    url: openapi/kit-broadcasts-api-openapi.yml
  - type: Documentation
    url: https://developers.kit.com/v4/api-reference
  - type: Authentication
    url: https://developers.kit.com/v4/api-reference/authentication
  - type: Webhooks
    url: https://developers.kit.com/v4/api-reference/webhooks
  - type: Migration
    url: https://developers.kit.com/v4/api-reference/v3-to-v4-upgrade-guide
  - type: AsyncAPI
    url: asyncapi/kit-webhooks-asyncapi.yml
- aid: kit:kit-subscribers-api
  name: Kit Subscribers API
  description: Subscriber records and lifecycle
  humanURL: https://developers.kit.com/v4/api-reference
  baseURL: https://api.kit.com/v4
  tags:
  - Subscribers
  properties:
  - type: OpenAPI
    url: openapi/kit-subscribers-api-openapi.yml
  - type: Documentation
    url: https://developers.kit.com/v4/api-reference
  - type: Authentication
    url: https://developers.kit.com/v4/api-reference/authentication
  - type: Webhooks
    url: https://developers.kit.com/v4/api-reference/webhooks
  - type: Migration
    url: https://developers.kit.com/v4/api-reference/v3-to-v4-upgrade-guide
  - type: AsyncAPI
    url: asyncapi/kit-webhooks-asyncapi.yml
common:
- type: AgenticAccess
  url: agentic-access/kit-agentic-access.yml
- type: TrustCenter
  url: security/kit-trust-center.yml
- type: VulnerabilityDisclosure
  url: security/kit-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/kit-domain-security.yml
- type: Authentication
  url: authentication/kit-authentication.yml
- type: OAuthScopes
  url: scopes/kit-scopes.yml
- type: GitHubOrganization
  url: https://github.com/kit
- type: Website
  url: https://kit.com/
- type: Portal
  url: https://developers.kit.com/
- type: Signup
  url: https://app.kit.com/users/signup
- type: Pricing
  url: https://kit.com/pricing
- type: Plans
  url: plans/kit-plans-pricing.yml
- type: RateLimits
  url: rate-limits/kit-rate-limits.yml
- type: FinOps
  url: finops/kit-finops.yml
- url: https://kit.com/resources/blog
  type: Blog
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com