Kit
Kit (formerly ConvertKit) is a creator email marketing platform whose REST API v4 covers subscribers, tags, custom fields, forms and landing pages, sequences, broadcasts, snippets, posts, purchases, segments and webhooks across 72 operations on https://api.kit.com/v4. It authenticates with an X-Kit-Api-Key header for personal automation or OAuth 2.0 (PKCE, dynamic client registration, rotating single-use refresh tokens) for apps published to the Kit App Store, and uses cursor-based pagination, an OAuth-only bulk namespace with async callbacks, and eventually-consistent list reads. Kit also runs two remote MCP servers - an OAuth-gated one that acts on a creator's account and an anonymous read-only documentation server - publishes an A2A agent card and an Agent Skill from its developer docs host, and ships llms.txt. Its only first-party API client is a PHP SDK.
Reference-quality API operations across every facet — a rich contract, published governance, transparent operations, and machine-readable commercial terms.
API Evangelist profiles Kit the way a machine reads it — 217 machine-readable artifacts across 1 API, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Kit scores 82.8/100 (exemplar), with a separate agent-readiness read of 55/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-09-08 · rubric v0.20.0
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How we profile Kit
Each block below is one kind of artifact we hold for Kit. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 16
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
Kit Accounts API
The Accounts API from Kit — 5 operation(s) for accounts.
Kit Broadcasts API
The Broadcasts API from Kit — 5 operation(s) for broadcasts.
Kit Custom Fields API
The Custom Fields API from Kit — 4 operation(s) for custom fields.
Kit Email Templates API
The Email Templates API from Kit — 1 operation(s) for email templates.
Kit Forms API
The Forms API from Kit — 4 operation(s) for forms.
Kit Posts API
The Posts API from Kit — 2 operation(s) for posts.
Kit Purchases API
The Purchases API from Kit — 2 operation(s) for purchases.
Kit Segments API
The Segments API from Kit — 1 operation(s) for segments.
Kit Sequence Emails API
The Sequence Emails API from Kit — 2 operation(s) for sequence emails.
Kit Sequences API
The Sequences API from Kit — 4 operation(s) for sequences.
Kit Snippets API
The Snippets API from Kit — 2 operation(s) for snippets.
Kit Subscribers API
The Subscribers API from Kit — 7 operation(s) for subscribers.
Kit Tags API
The Tags API from Kit — 6 operation(s) for tags.
Kit Webhooks API
The Webhooks API from Kit — 2 operation(s) for webhooks.
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
Scroll within the panel for all 16 ·
Open Collections 15
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
API Collection
OPEN COLLECTIONKit Accounts API
OPEN COLLECTIONKit Accounts Broadcasts API
OPEN COLLECTIONKit Accounts Custom Fields API
OPEN COLLECTIONKit Accounts Email Templates API
OPEN COLLECTIONKit Accounts Forms API
OPEN COLLECTIONKit Accounts Posts API
OPEN COLLECTIONKit Accounts Purchases API
OPEN COLLECTIONKit Accounts Segments API
OPEN COLLECTIONKit Accounts Sequence Emails API
OPEN COLLECTIONKit Accounts Sequences API
OPEN COLLECTIONKit Accounts Snippets API
OPEN COLLECTIONKit Accounts Subscribers API
OPEN COLLECTIONKit Accounts Tags API
OPEN COLLECTIONKit Accounts Webhooks API
OPEN COLLECTIONScroll within the panel for all 15 ·
MCP Servers 1
Model Context Protocol servers expose these APIs directly to AI agents. We profile them because agent-native access is the fastest-growing way this provider's capabilities actually get used.
Model Context Protocol servers that expose these APIs to AI agents.
Kit MCP Server
MCP SERVERGraphQL 1
Where a provider ships GraphQL, the schema is the contract. We profile it alongside the REST surface so the whole interface is legible in one place.
GraphQL schemas published by this provider.
Kit (ConvertKit) GraphQL API
Kit (formerly ConvertKit) is a creator email marketing platform. This conceptual GraphQL schema wraps the Kit REST API v4, providing queries for subscribers, tags, sequences, fo...
GRAPHQLPricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the things the Kin Score reads for access clarity — renamed from commercial clarity in rubric 0.12, because a free statutory interface has access terms and no commercial ones.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Convertkit Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
Convertkit Finops
FINOPSEvent Specifications 2
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Convertkit Webhooks
ASYNCAPIKit 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...
ASYNCAPISpectral Rules 1
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
Kit API Rules
SPECTRALJSON Schema 100
Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.
Standalone JSON Schema definitions for this provider's data models.
BroadcastAnyCondition
JSON SCHEMAFilterCondition
JSON SCHEMAFormsAnyCondition
JSON SCHEMAIdsAnyCondition
JSON SCHEMASubscriberFilterRequest
JSON SCHEMAUrlAnyCondition
JSON SCHEMAAdd subscriber to form Request
JSON SCHEMAAdd subscriber to form Response
JSON SCHEMAAdd subscriber to sequence Request
JSON SCHEMAAdd subscriber to sequence Response
JSON SCHEMABulk add subscribers to forms Request
JSON SCHEMABulk add subscribers to forms Response
JSON SCHEMABulk create custom fields Request
JSON SCHEMABulk create custom fields Response
JSON SCHEMABulk create subscribers Request
JSON SCHEMABulk create subscribers Response
JSON SCHEMABulk create tags Request
JSON SCHEMABulk create tags Response
JSON SCHEMABulk remove tags from subscribers Response
JSON SCHEMABulk tag subscribers Request
JSON SCHEMABulk tag subscribers Response
JSON SCHEMACreate a broadcast Request
JSON SCHEMACreate a broadcast Response
JSON SCHEMACreate a custom field Request
JSON SCHEMACreate a custom field Response
JSON SCHEMACreate a purchase Request
JSON SCHEMACreate a purchase Response
JSON SCHEMACreate a sequence email Request
JSON SCHEMACreate a sequence email Response
JSON SCHEMACreate a sequence Request
JSON SCHEMACreate a sequence Response
JSON SCHEMACreate a snippet Request
JSON SCHEMACreate a snippet Response
JSON SCHEMACreate a subscriber Request
JSON SCHEMACreate a subscriber Response
JSON SCHEMACreate a tag Request
JSON SCHEMACreate a tag Response
JSON SCHEMACreate a webhook Request
JSON SCHEMACreate a webhook Response
JSON SCHEMAGet a broadcast Response
JSON SCHEMAGet a post Response
JSON SCHEMAGet a purchase Response
JSON SCHEMAGet a sequence email Response
JSON SCHEMAGet a sequence Response
JSON SCHEMAGet a snippet Response
JSON SCHEMAGet a subscriber Response
JSON SCHEMAGet Creator Profile Response
JSON SCHEMAGet current account Response
JSON SCHEMAGet email stats Response
JSON SCHEMAGet growth stats Response
JSON SCHEMAGet link clicks for a broadcast Response
JSON SCHEMAGet stats for a broadcast Response
JSON SCHEMAGet stats for a list of broadcasts Response
JSON SCHEMAList broadcasts Response
JSON SCHEMAList colors Response
JSON SCHEMAList custom fields Response
JSON SCHEMAList email templates Response
JSON SCHEMAList forms Response
JSON SCHEMAList posts Response
JSON SCHEMAList purchases Response
JSON SCHEMAList segments Response
JSON SCHEMAList sequence emails Response
JSON SCHEMAList sequences Response
JSON SCHEMAList snippets Response
JSON SCHEMAList stats for a subscriber Response
JSON SCHEMAList subscribers for a form Response
JSON SCHEMAList subscribers for a sequence Response
JSON SCHEMAList subscribers for a tag Response
JSON SCHEMAList subscribers Response
JSON SCHEMAList tags for a subscriber Response
JSON SCHEMAList tags Response
JSON SCHEMAList webhooks Response
JSON SCHEMATag a subscriber by email address Request
JSON SCHEMATag a subscriber by email address Response
JSON SCHEMATag a subscriber Request
JSON SCHEMATag a subscriber Response
JSON SCHEMAUnsubscribe subscriber Request
JSON SCHEMAUpdate a broadcast Request
JSON SCHEMAUpdate a broadcast Response
JSON SCHEMAUpdate a custom field Request
JSON SCHEMAUpdate a custom field Response
JSON SCHEMAUpdate a sequence email Request
JSON SCHEMAUpdate a sequence email Response
JSON SCHEMAUpdate a sequence Request
JSON SCHEMAUpdate a sequence Response
JSON SCHEMAUpdate a snippet Request
JSON SCHEMAUpdate a snippet Response
JSON SCHEMAUpdate a subscriber Request
JSON SCHEMAUpdate a subscriber Response
JSON SCHEMAUpdate colors Request
JSON SCHEMAUpdate colors Response
JSON SCHEMAUpdate tag name Request
JSON SCHEMAUpdate tag name Response
JSON SCHEMAScroll within the panel for all 100 ·
Examples 72
Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.
Example request and response payloads for these APIs.
Add Subscriber To Form
EXAMPLEAdd Subscriber To Sequence
EXAMPLEBulk Create Custom Fields
EXAMPLEBulk Create Subscribers
EXAMPLEBulk Create Tags
EXAMPLEBulk Tag Subscribers
EXAMPLECreate A Broadcast
EXAMPLECreate A Custom Field
EXAMPLECreate A Purchase
EXAMPLECreate A Sequence Email
EXAMPLECreate A Sequence
EXAMPLECreate A Snippet
EXAMPLECreate A Subscriber
EXAMPLECreate A Tag
EXAMPLECreate A Webhook
EXAMPLEDelete A Broadcast
EXAMPLEDelete A Sequence Email
EXAMPLEDelete A Sequence
EXAMPLEDelete A Webhook
EXAMPLEDelete Custom Field
EXAMPLEGet A Broadcast
EXAMPLEGet A Post
EXAMPLEGet A Purchase
EXAMPLEGet A Sequence Email
EXAMPLEGet A Sequence
EXAMPLEGet A Snippet
EXAMPLEGet A Subscriber
EXAMPLEGet Creator Profile
EXAMPLEGet Current Account
EXAMPLEGet Email Stats
EXAMPLEGet Growth Stats
EXAMPLEGet Stats For A Broadcast
EXAMPLEList Broadcasts
EXAMPLEList Colors
EXAMPLEList Custom Fields
EXAMPLEList Email Templates
EXAMPLEList Forms
EXAMPLEList Posts
EXAMPLEList Purchases
EXAMPLEList Segments
EXAMPLEList Sequence Emails
EXAMPLEList Sequences
EXAMPLEList Snippets
EXAMPLEList Stats For A Subscriber
EXAMPLEList Subscribers For A Form
EXAMPLEList Subscribers For A Tag
EXAMPLEList Subscribers
EXAMPLEList Tags For A Subscriber
EXAMPLEList Tags
EXAMPLEList Webhooks
EXAMPLERemove Tag From Subscriber
EXAMPLETag A Subscriber
EXAMPLEUnsubscribe Subscriber
EXAMPLEUpdate A Broadcast
EXAMPLEUpdate A Custom Field
EXAMPLEUpdate A Sequence Email
EXAMPLEUpdate A Sequence
EXAMPLEUpdate A Snippet
EXAMPLEUpdate A Subscriber
EXAMPLEUpdate Colors
EXAMPLEUpdate Tag Name
EXAMPLEScroll within the panel for all 72 ·
Security Posture 4
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Scopes 1
OAuth scopes are the vocabulary of least-privilege access. Profiling them shows exactly what an integration — or an agent acting on a user's behalf — is allowed to do.
OAuth scopes governing access to this provider's APIs.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Kit — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 3
Portal, sign-up, and the first successful call
Documentation 2
Reference material describing how the API behaves
Agent Surfaces 5
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 11
Pagination, idempotency, versioning, errors, and events
Scroll within the panel for all 11 ·
Build 76
SDKs, sample code, and the tooling you integrate with
Scroll within the panel for all 76 ·
Access & Security 7
Authentication, authorization, and security posture
Scroll within the panel for all 7 ·
Operate 6
Status, limits, changes, and where to get help
Commercial 5
Pricing, plans, and the legal terms of use
Company 3
The organization behind the API
Other 3
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/convertkit · machine-readable index on apis.io
This is an independent, third-party profile of Kit, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
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