Campaign Monitor

Campaign Monitor, a Marigold brand, is an email marketing platform for marketers and agencies. Its REST API — served under the original createsend name at api.createsend.com/api/v3.3 — manages clients, subscriber lists, subscribers and custom fields, segments, campaigns, HTML templates, automated journeys, authenticated sending domains and transactional email, and returns per-recipient reporting for opens, clicks, bounces, unsubscribes and spam complaints. Authentication is OAuth 2.0 with twelve coarse permissions, or an API key over HTTP Basic. Per-list webhooks push Subscribe, Update and Deactivate events. Campaign Monitor publishes no OpenAPI, no AsyncAPI and no MCP server; the contract is HTML reference documentation plus seven official client libraries.

Campaign Monitor is listed with 3 APIs on the APIs.io network. Tagged areas include Email Marketing, Campaigns, Subscribers, Transactional Email, and Segments.

The Campaign Monitor catalog on APIs.io includes 1 event-driven AsyncAPI specification, 1 JSON-LD context, and 1 Spectral governance ruleset.

Campaign Monitor’s developer surface includes documentation, engineering blog, pricing, API reference, getting-started guide, support, signup flow, and 40 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

65.3/100 strong ▬ flat Agent 29/100 agent ready Front door AI 4/6 moderate Heartbeat 30/100 slowing saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessFreemiumSelf serveFree trial⚡ Free to try

3 APIs

Email Marketing Campaigns Subscribers Transactional Email Segments Newsletters Automation Marketing Automation Webhook Email Deliverability Marketing

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 65.3/100 · strong

Contract Quality 6.0 / 19

Developer Ergonomics 9.1 / 15

Access Clarity 15.0 / 15

Operational Transparency 8.2 / 10

Contract Governance 3.2 / 9

Discoverability 5.4 / 8

Regulatory Posture 6.6 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 29/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 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

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Telecommunications regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented)

7 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 31.8 — up to +17.1 composite points
Developer Ergonomics scores 60.7 — up to +7.9 composite points
Contract Governance scores 35.6 — up to +7.7 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/campaignmonitor/apis.yml: open an issue on github.com/api-evangelist/campaignmonitor to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
HubSpot App Marketplace (CRM add-ons, outbound, performance marketing, chat)	builds-on	20.3	-	-
IFTTT Services (service publishers)	builds-on	20.3	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

APIs 3

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

Campaign Monitor API

REST API for managing email campaigns, subscriber lists, transactional emails, segments, journeys, templates, and campaign performance analytics.

Campaign Monitor SOAP API (legacy createsend)

Legacy ASP.NET SOAP web service still served at api.createsend.com/api/api.asmx, the same host as the REST v3.3 API. Its WSDL (targetNamespace http://api.createsend.com/api/) de...

Campaign Monitor API

Campaign Monitor API as documented publicly: 6 operations. Contract generated from the documentation by API Evangelist (2026-10-21); not the provider's own document.

Campaign Monitor API pricing

Prices published by Campaign Monitor.

Plan	Price
Free Trial	500 contacts for the 30-day free trial
Lite	$/month
Essentials	$/month
Premier	$/month
Enterprise	Custom pricing tailored to your volume and goals.

Plan details, limits and sources →

Rate limits

Transactional endpoint rate limit: All /transactional endpoints are subject to API rate limiting

Rate-limit details →

Billed by: subscription · FinOps profile →

Pricing Plans 1

Published pricing tiers and plan structures.

Campaignmonitor Plans Pricing

5 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Campaignmonitor Rate Limits

1 limits

RATE LIMITS

FinOps 1

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

Campaignmonitor Finops

FINOPS

Event Specifications 1

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

Campaignmonitor Webhooks

ASYNCAPI

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Campaignmonitor Context

18 classes · 1 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Campaign Monitor API Rules

10 rules · 8 errors 1 warnings 1 info

SPECTRAL

JSON Schema 5

Standalone JSON Schema definitions for this provider's data models.

GetApiApiidClientsJsonResponse

2 properties

JSON SCHEMA

GetApiV32ClientsXmlResponse

2 properties

JSON SCHEMA

PostApiV32ClientsJsonRequest

5 properties

JSON SCHEMA

PostApiV32ClientsXmlRequest

5 properties

JSON SCHEMA

PostDeactivateRequest

2 properties

JSON SCHEMA

Security Posture 4

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

Campaignmonitor Authentication

oauth2/http · 2 schemes

SECURITY

Campaignmonitor Domain Security

TLSv1.3 · DMARC

SECURITY

Campaignmonitor Vulnerability Disclosure

Bugcrowd · security.txt · contact published

SECURITY

Campaignmonitor Trust Center

SOC 2, GDPR

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Campaignmonitor Scopes

12 scopes

SCOPES

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Login

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

WellKnown

WellKnown

X-MCPServerCandidate

X-MCPServerCandidate

Design & Contract 10

Pagination, idempotency, versioning, errors, and events

Spectral

JSONLD

Vocabulary

JSONLDContext

Conformance

Conventions

ErrorCatalog

Lifecycle

DataModel

Webhooks

Scroll for all 10

Build 4

SDKs, sample code, and the tooling you integrate with

IntegrationEdges

GitHubOrg

Packages

SDKs

Access & Security 8

Authentication, authorization, and security posture

TrustCenter

TrustCenter

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

SecurityTxt

Security

Compliance

Authentication

OAuthScopes

Scroll for all 8

Operate 5

Status, limits, changes, and where to get help

Deprecation

StatusPage

RateLimits

Support

ChangeLog

Commercial 5

Pricing, plans, and the legal terms of use

Pricing

Plans

FinOps

TermsOfService

PrivacyPolicy

Company 4

The organization behind the API

Website

Website

LinkedIn

Blog

Blog

BlogPosts

BlogPosts

Other 3

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: campaignmonitor
name: Campaign Monitor
description: Campaign Monitor, a Marigold brand, is an email marketing platform for marketers and agencies. Its REST API —
  served under the original createsend name at api.createsend.com/api/v3.3 — manages clients, subscriber lists, subscribers
  and custom fields, segments, campaigns, HTML templates, automated journeys, authenticated sending domains and transactional
  email, and returns per-recipient reporting for opens, clicks, bounces, unsubscribes and spam complaints. Authentication
  is OAuth 2.0 with twelve coarse permissions, or an API key over HTTP Basic. Per-list webhooks push Subscribe, Update and
  Deactivate events. Campaign Monitor publishes no OpenAPI, no AsyncAPI and no MCP server; the contract is HTML reference
  documentation plus seven official client libraries.
type: Index
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: true
  try_now: true
  public: false
  gated: none
  gated_source:
  - onboarding
  label: Freemium (free trial) · Self-serve signup
  confidence: high
  probe_state: covered
  source:
  - plans
  - authentication
  - scopes
  - rate-limits
  - security
  generated: '2026-11-06'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/campaignmonitor.png
url: https://raw.githubusercontent.com/api-evangelist/campaignmonitor/refs/heads/main/apis.yml
created: '2026-06-13'
modified: '2026-10-21'
specificationVersion: '0.23'
tags:
- Email Marketing
- Campaigns
- Subscribers
- Transactional Email
- Segments
- Newsletters
- Automation
- Marketing Automation
- Webhook
- Email Deliverability
- Marketing
tags_raw:
- Email Marketing
- Campaigns
- Subscribers
- Transactional Email
- Segments
- Newsletters
- Automation
- Marketing Automation
- Webhooks
- Email Deliverability
- Marketing
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
common:
- type: Spectral
  url: rules/campaignmonitor-rules.yml
- type: JSONLD
  url: json-ld/campaignmonitor-context.jsonld
- type: Vocabulary
  url: vocabulary/campaignmonitor-vocabulary.yml
- type: Deprecation
  url: lifecycle/campaignmonitor-lifecycle.yml
- type: Hosts
  url: hosts/campaignmonitor-hosts.yml
- type: IntegrationEdges
  url: integrations/campaignmonitor-integration-edges.yml
- type: Vendors
  url: vendors/campaignmonitor-vendors.yml
- type: TrustCenter
  url: security/campaignmonitor-trust-center.yml
- type: VulnerabilityDisclosure
  url: security/campaignmonitor-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/campaignmonitor-domain-security.yml
- type: Website
  url: https://www.campaignmonitor.com/
- type: Documentation
  url: https://www.campaignmonitor.com/api/
- type: GitHubOrg
  url: https://github.com/campaignmonitor
- type: LinkedIn
  url: https://www.linkedin.com/company/campaign-monitor
- type: Blog
  url: https://www.campaignmonitor.com/blog/
- type: Pricing
  url: https://www.campaignmonitor.com/pricing/
- type: StatusPage
  url: https://status.campaignmonitor.com/
- type: X
  url: https://x.com/campaignmonitor
- type: Plans
  url: plans/campaignmonitor-plans-pricing.yml
- type: RateLimits
  url: rate-limits/campaignmonitor-rate-limits.yml
- type: FinOps
  url: finops/campaignmonitor-finops.yml
- type: BlogPosts
  url: blogs/blogs.json
- type: JSONLDContext
  url: json-ld/campaignmonitor-context.jsonld
- type: DeveloperPortal
  url: https://www.campaignmonitor.com/api/
- type: APIReference
  url: https://www.campaignmonitor.com/api/v3-3/
- type: GettingStarted
  url: https://www.campaignmonitor.com/api/v3-3/getting-started/
- type: Support
  url: https://help.campaignmonitor.com/
- type: SignUp
  url: https://www.campaignmonitor.com/signup/
- type: Login
  url: https://login.createsend.com/
- type: TermsOfService
  url: https://www.campaignmonitor.com/policies/#terms-of-use
- type: PrivacyPolicy
  url: https://www.campaignmonitor.com/policies/#privacy-policy
- type: Integrations
  url: https://www.campaignmonitor.com/integrations/
- type: Packages
  url: packages/campaignmonitor-packages.yml
- type: SDKs
  url: packages/campaignmonitor-packages.yml
- type: WellKnown
  url: well-known/campaignmonitor-well-known.yml
- type: SecurityTxt
  url: well-known/campaignmonitor-security.txt
- type: Security
  url: security/campaignmonitor-vulnerability-disclosure.yml
- type: Compliance
  url: conformance/campaignmonitor-conformance.yml
- type: Conformance
  url: conformance/campaignmonitor-conformance.yml
- type: Authentication
  url: authentication/campaignmonitor-authentication.yml
- type: OAuthScopes
  url: scopes/campaignmonitor-scopes.yml
- type: Conventions
  url: conventions/campaignmonitor-conventions.yml
- type: ErrorCatalog
  url: errors/campaignmonitor-error-codes.yml
- type: Lifecycle
  url: lifecycle/campaignmonitor-lifecycle.yml
- type: ChangeLog
  url: changelog/campaignmonitor-changelog.yml
- type: DataModel
  url: data-model/campaignmonitor-data-model.yml
- type: Webhooks
  url: asyncapi/campaignmonitor-webhooks.yml
- type: X-MCPServerCandidate
  url: mcp/campaignmonitor-mcp.yml
  note: 'Renamed from MCPServer 2026-09-03 (roadmap#247): the manifest self-describes as status: candidate — a tool list derived
    from the published API contracts, not an existing server. The scorer already read the manifest and reported mcp_server
    correctly; the MCPServer type was crediting the artifact-type surfaces with a server that does not exist.'
apis:
- aid: campaignmonitor:campaign-monitor-api
  name: Campaign Monitor API
  description: REST API for managing email campaigns, subscriber lists, transactional emails, segments, journeys, templates,
    and campaign performance analytics.
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  humanURL: https://www.campaignmonitor.com/api/
  baseURL: https://api.createsend.com/api/v3.3/
  tags:
  - Email Marketing
  - Campaigns
  - Subscribers
  - Transactional Email
  - Segments
  - Webhook
  tags_raw:
  - Email Marketing
  - Campaigns
  - Subscribers
  - Transactional Email
  - Segments
  - Webhooks
  properties:
  - type: Documentation
    url: https://www.campaignmonitor.com/api/v3-3/getting-started/
  - type: GettingStarted
    url: https://www.campaignmonitor.com/api/v3-3/getting-started/
  - type: Authentication
    url: authentication/campaignmonitor-authentication.yml
  - type: OAuthScopes
    url: scopes/campaignmonitor-scopes.yml
  - type: ErrorCatalog
    url: errors/campaignmonitor-error-codes.yml
  - type: DataModel
    url: data-model/campaignmonitor-data-model.yml
  - type: Webhooks
    url: asyncapi/campaignmonitor-webhooks.yml
  - type: Conventions
    url: conventions/campaignmonitor-conventions.yml
  contact:
  - FN: Campaign Monitor Support
    url: https://help.campaignmonitor.com/
- aid: campaignmonitor:createsend-soap-api
  name: Campaign Monitor SOAP API (legacy createsend)
  description: Legacy ASP.NET SOAP web service still served at api.createsend.com/api/api.asmx, the same host as the REST
    v3.3 API. Its WSDL (targetNamespace http://api.createsend.com/api/) declares 50 SOAP operations (plus HTTP GET/POST bindings)
    for subscribers, lists, clients and campaigns, such as AddSubscriberWithCustomFields, Unsubscribe and GetSubscribers.
    The current developer docs describe only the REST API; the WSDL is saved verbatim as served.
  humanURL: https://api.createsend.com/api/api.asmx
  baseURL: https://api.createsend.com/api/api.asmx
  tags:
  - Email Marketing
  - Subscribers
  - SOAP
  properties:
  - type: WSDL
    url: wsdl/campaignmonitor-createsend-api.wsdl
  - type: WSDL
    name: WSDL (provider-hosted)
    url: https://api.createsend.com/api/api.asmx?wsdl
- aid: campaignmonitor:campaignmonitor-api
  name: Campaign Monitor API
  description: 'Campaign Monitor API as documented publicly: 6 operations. Contract generated from the documentation by API
    Evangelist (2026-10-21);

    not the provider''s own document.'
  humanURL: https://www.campaignmonitor.com/api/v3-3/webhooks
  baseURL: https://api.createsend.com
  properties:
  - type: OpenAPI
    url: openapi/_ae-authored/campaignmonitor-openapi-generated.yml
    x-provenance: generated
  - type: JSONSchema
    url: json-schema/campaignmonitor-post-api-v32-clients-json-request-schema.json
  - type: JSONSchema
    url: json-schema/campaignmonitor-post-api-v32-clients-xml-request-schema.json
  - type: JSONSchema
    url: json-schema/campaignmonitor-post-deactivate-request-schema.json
  - type: JSONSchema
    url: json-schema/campaignmonitor-get-api-apiid-clients-json-response-schema.json
  - type: JSONSchema
    url: json-schema/campaignmonitor-get-api-v32-clients-xml-response-schema.json
x-coverage:
  state: covered
  reason: no-machine-readable-spec
  detail: 'The API is fully public and richly documented in HTML — 117 operations, 240 numeric error codes, 12 OAuth permissions
    and a webhook catalog were all read straight off campaignmonitor.com/api/v3-3/ — but Campaign Monitor publishes no OpenAPI:
    /openapi.json, /swagger.json, /api-docs and /docs all 404 on api.createsend.com, and there is no MCP server, no AsyncAPI
    and no agent card.'
  evidence:
  - url: https://api.createsend.com/openapi.json
    status: 404
  - url: https://api.createsend.com/swagger.json
    status: 404
  - url: https://www.campaignmonitor.com/api/v3-3/getting-started/
    status: 200
  - url: https://www.campaignmonitor.com/
    status: 200
  - url: https://www.campaignmonitor.com/api/v3-3/
    status: 200
  - url: https://www.campaignmonitor.com/.well-known/security.txt
    status: 200
  - url: https://www.campaignmonitor.com/.well-known/agent-card.json
    status: 404
  checked: '2026-08-13'
x-enrichment:
  date: '2026-10-21'
  status: enriched
  artifacts_added: 12
  pass: modular-v1
  engine: identity=anthropic,contract=anthropic,surfaces=anthropic,docs=anthropic,regulatory=anthropic

Campaign Monitor API — frequently asked questions

Does Campaign Monitor have an API?

Yes. APIs.io lists 3 APIs from Campaign Monitor, including Campaign Monitor API, Campaign Monitor SOAP API (legacy createsend) and Campaign Monitor API.

Is there an OpenAPI specification for the Campaign Monitor API?

Yes. APIs.io indexes 1 OpenAPI specification for Campaign Monitor, each linked for download from this page.

How do I authenticate with the Campaign Monitor API?

Campaign Monitor uses bearer-token authentication (oauth2/http · 2 schemes). The details are profiled on APIs.io as Campaignmonitor Authentication.

How much does the Campaign Monitor API cost?

Campaign Monitor publishes its prices; its Lite plan is $/month as of 2026-10-21. APIs.io lists 5 pricing plans for Campaign Monitor, with each plan's price, limits and inclusions under Pricing on this page.

Is the Campaign Monitor API ready for AI agents?

Campaign Monitor has a Kin Score of 65.3 out of 100 (strong) and an Agent Readiness score of 29.2 (agent-ready), scored by API Evangelist on 2026-11-06.

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