AddCal

AddCal provides a suite of tools that let users create calendar event links, manage RSVPs, and embed calendars on websites. Their platform supports smart links, subscription calendars, and automated email invites, aiming to increase event attendance. The service offers a free tier with unlimited events and paid plans for advanced features, targeting event organizers, marketers, and developers needing seamless calendar integration.

AddCal is profiled on the APIs.io network. Tagged areas include Calendar, Event Management, Software-as-a-Service, Integration, and Productivity.

AddCal’s developer surface includes support, changelog, getting-started guide, documentation, API reference, pricing, engineering blog, and 17 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

18.3/100 emerging ▼ -11.5 Agent 25/100 agent aware Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

0 APIs

Calendar Event Management Software-as-a-Service Integration Productivity Company

Kin Score

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

Composite quality — 18.3/100 · emerging

Contract Quality 0.0 / 21

Developer Ergonomics 3.0 / 17

Access Clarity 5.8 / 17

Operational Transparency 1.5 / 11

Contract Governance 0.0 / 10

Discoverability 4.1 / 9

Regulatory Posture 3.6 / 15

Agent readiness — 25/100 · agent aware

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 4 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 6 / 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 Horizontal (data, software, accessibility, platform) 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 could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

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/.

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

Machine-Readable Contract +18 pts — api_specs includes an OpenAPI document
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)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (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 0.0 — up to +25.0 composite points
Developer Ergonomics scores 17.9 — up to +16.4 composite points
Access Clarity scores 34.2 — up to +13.2 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/addcal-co/apis.yml: open an issue on github.com/api-evangelist/addcal-co 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 →

Standards implemented 3

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

Model Context Protocol (MCP)

measured — observed by APIs.io (documented)

OAuth 2.0 Protected Resource Metadata

measured — observed by APIs.io (verified)

Dynamic Client Registration

measured — observed by APIs.io (published)

Security Posture 3

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

Addcal Co Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Addcal Co Vulnerability Disclosure

security.txt · contact published

SECURITY

Addcal Co Trust Center

SOC 2, PCI DSS, HIPAA, GDPR

SECURITY

Resources

Get Started 2

Portal, sign-up, and the first successful call

Login

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

WellKnown

WellKnown

Access & Security 9

Authentication, authorization, and security posture

Compliance

SecurityTxt

SecurityTxt

SecurityTxt

SecurityTxt

Security

TrustCenter

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Scroll for all 9

Operate 2

Status, limits, changes, and where to get help

Support

Support

ChangeLog

ChangeLog

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 2

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: addcal-co
name: AddCal
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  probe_state: unreadable
  source:
  - security
  generated: '2026-11-06'
  method: derived
image: https://cdn.addcal.co/static/og.webp
description: AddCal provides a suite of tools that let users create calendar event links, manage RSVPs, and embed calendars
  on websites. Their platform supports smart links, subscription calendars, and automated email invites, aiming to increase
  event attendance. The service offers a free tier with unlimited events and paid plans for advanced features, targeting event
  organizers, marketers, and developers needing seamless calendar integration.
url: https://artifacts.apis.io/addcal-co/apis.yml
x-type: company
x-source: harvest:mcp-registry
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-31 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-31'
modified: '2026-10-31'
tags:
- Calendar
- Event Management
- Software-as-a-Service
- Integration
- Productivity
- Company
tags_raw:
- Calendar
- Event Management
- SaaS
- Integration
- Productivity
- Company
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Compliance
  url: https://addcal.co/security
- type: LLMsTxt
  url: llms/addcal-co-llms.txt
- type: SecurityTxt
  url: well-known/addcal-co-security.txt
- type: SecurityTxt
  url: well-known/addcal-co-help-security.txt
- type: SecurityTxt
  url: well-known/addcal-co-dev-security.txt
- type: SecurityTxt
  url: well-known/addcal-co-cdn-security.txt
- type: WellKnown
  url: well-known/addcal-co-well-known.yml
- type: Hosts
  url: hosts/addcal-co-hosts.yml
- type: Vendors
  url: vendors/addcal-co-vendors.yml
- type: Support
  url: https://help.addcal.co/en/
- type: Security
  url: https://addcal.co/security
- type: Login
  url: https://addcal.co/login
- type: ChangeLog
  url: https://addcal.co/changelog
- type: GettingStarted
  url: https://help.addcal.co/en/articles/12087166-rsvp-quick-start-guide-addcal
- type: TrustCenter
  url: security/addcal-co-trust-center.yml
- type: VulnerabilityDisclosure
  url: security/addcal-co-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/addcal-co-domain-security.yml
- type: Website
  url: https://addcal.co/
- type: Documentation
  url: https://addcal.co/documentation
- type: APIReference
  url: https://addcal.co/documentation/api
- type: Pricing
  url: https://addcal.co/pricing
- type: Blog
  url: https://addcal.co/blog
- type: TermsOfService
  url: https://addcal.co/terms-of-service
- type: PrivacyPolicy
  url: https://addcal.co/privacy-policy
apis: []
x-coverage:
  state: unreadable
  reason: no-machine-readable-spec
  detail: Documentation page provides only HTML without a downloadable OpenAPI spec.
  evidence:
  - url: https://addcal.co/documentation/api
    status: 200
  checked: '2026-10-31'
x-enrichment:
  date: '2026-10-31'
  status: enriched
  artifacts_added: 21
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

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