Campaign Monitor website screenshot

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 publishes 1 API 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 and 1 JSON-LD context.

Campaign Monitor’s developer surface includes documentation, engineering blog, pricing, getting-started guide, support, signup flow, authentication, and 33 more developer resources.

🌐 Visit website 📡 Source on GitHub
72.9/100 exemplar ▬ flat Agent 38/100 agent ready Full breakdown ↓
scored 2026-08-20 · rubric v0.12.0
AccessFreemiumFree trial
1 APIs 1 MCP Servers
Email MarketingCampaignsSubscribersTransactional EmailSegmentsNewslettersAutomationMarketing AutomationWebhookEmail DeliverabilityMarketing

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-20 · rubric v0.12.0
Composite quality — 72.9/100 · exemplar
Contract Quality 12.0 / 21
Developer Ergonomics 9.7 / 17
Access Clarity 17.0 / 17
Operational Transparency 8.4 / 11
Contract Governance 1.9 / 10
Discoverability 7.4 / 9
Regulatory Posture 11.0 / 15
Agent readiness — 38/100 · 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 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 6 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 3 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
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.
The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.
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/campaignmonitor: 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 1

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.

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

Campaign Monitor MCP Server

MCP SERVER

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

2 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

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

OAuth 2.0 · no documented scopes

0 scopes

SCOPES

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal
DeveloperPortal
 GettingStarted
GettingStarted
 SignUp
SignUp
 Login
Login

Documentation 1

Reference material describing how the API behaves

Documentation
Documentation

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

WellKnown
WellKnown
 MCPServer
MCPServer
 LLMsTxt
LLMsTxt

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

JSONLDContext
JSONLDContext
 Conformance
Conformance
 Conventions
Conventions
 ErrorCatalog
ErrorCatalog
 Lifecycle
Lifecycle
 DataModel
DataModel
 Webhooks
Webhooks

Scroll for all 7

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrg
GitHubOrg
 Packages
Packages
 SDKs
SDKs

Access & Security 8

Authentication, authorization, and security posture

TrustCenter
TrustCenter
 VulnerabilityDisclosure
VulnerabilityDisclosure
 DomainSecurity
DomainSecurity
 SecurityTxt
SecurityTxt
 Security
Security
 Compliance
Compliance
 Authentication
Authentication
 OAuthScopes
OAuthScopes

Scroll for all 8

Operate 4

Status, limits, changes, and where to get help

StatusPage
StatusPage
 RateLimits
RateLimits
 Support
Support
 ChangeLog
ChangeLog

Commercial 5

Pricing, plans, and the legal terms of use

Pricing
Pricing
 Plans
Plans
 FinOps
FinOps
 TermsOfService
TermsOfService
 PrivacyPolicy
PrivacyPolicy

Company 4

The organization behind the API

Website
Website
 LinkedIn
LinkedIn
 Blog
Blog
 BlogPosts
BlogPosts

Other 1

Properties that don't map to a standard resource type

X
X

Source (apis.yml)

apis.yml Raw ↑ 
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
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: true
  try_now: false
  public: false
  label: Freemium (free trial)
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  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: '2026-08-13'
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
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/
common:
- 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: 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: MCPServer
  url: mcp/campaignmonitor-mcp.yml
- type: LLMsTxt
  url: llms/campaignmonitor-llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
x-enrichment:
  date: '2026-08-13'
  status: enriched
  artifacts_added: 14
  pass: local-v1
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/.well-known/security.txt
    status: 200
  - url: https://www.campaignmonitor.com/.well-known/agent-card.json
    status: 404
  checked: '2026-08-13'