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Calendarific

Worldwide public holidays REST API covering 230+ countries. Calendarific provides national, local, religious, and observance holiday data with localization across many ISO-639 languages. Used for ecommerce scheduling, HR systems, travel planning, payroll, and global operations.

agent ready

Solid contracts, transparent operations, and an easy start — typically complete on four or five facets with one clear soft spot.

Kin Score

API Evangelist profiles Calendarific the way a machine reads it — 41 machine-readable artifacts across 3 APIs, 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 — Calendarific scores 65.2/100 (strong), with a separate agent-readiness read of 48/100 (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.

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 65.2/100 · strong
Contract Quality 19.5 / 25
Developer Ergonomics 7.8 / 20
Commercial Clarity 16.8 / 20
Operational Transparency 0.7 / 13
Governance 10.4 / 12
Discoverability 10.0 / 10
Agent readiness — 48/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 15 / 15
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 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3

How we profile Calendarific

Each block below is one kind of artifact we hold for Calendarific. 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 3

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.

Calendarific Countries API

List supported countries and their ISO codes.

Calendarific Holidays API

Retrieve holiday data for any country and year.

Calendarific Languages API

List supported languages and their ISO codes.

Open Collections 1

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).

Calendarific Holiday API

OPEN COLLECTION

Pricing 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 six things the Kin Score reads for commercial clarity.

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.

Calendarific Rate Limits

0 limits

RATE LIMITS

FinOps 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.

Features 7

The notable capabilities this provider advertises, captured as structured features so they can be searched and compared instead of read one landing page at a time.

Notable capabilities this provider offers.

230+ Countries

Coverage of national holidays across more than 230 countries.

Multi-Language Localization

Holiday names and descriptions in many ISO-639 languages (premium).

Holiday Type Filtering

Filter by national, local, religious, or observance categories.

Sub-Region Filtering

Filter by ISO-3166-2 state or region codes.

Historical and Future Data

Holidays from historical years through 2049.

CSV and XLS Export

Download holiday data as flat files in addition to API access.

Multiple API Keys

Multiple keys per account for environment separation.

Scroll within the panel for all 7 ·

Semantic Vocabularies 1

JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.

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

Calendarific Context

18 classes · 2 properties

JSON-LD

Spectral Rules 2

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.

Calendarific API Rules

5 rules · 4 warnings

SPECTRAL

Calendarific API Rules

6 rules · 2 errors · 4 warnings

SPECTRAL

JSON Schema 3

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.

Country

5 properties

JSON SCHEMA

Holiday

11 properties

JSON SCHEMA

Language

2 properties

JSON SCHEMA

JSON Structure 3

JSON Structure captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.

JSON Structure definitions describing this provider's data shapes.

Calendarific Country Structure

5 properties

JSON STRUCTURE

Calendarific Holiday Structure

10 properties

JSON STRUCTURE

Calendarific Language Structure

2 properties

JSON STRUCTURE

Examples 3

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.

Security Posture 2

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.

Calendarific Authentication

apiKey · 1 scheme

SECURITY

Calendarific Domain Security

TLSv1.3 · DMARC

SECURITY

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.

Calendarific Agentic Access

3 operations

3 operations · 0 acting

AGENTIC

Use Cases 6

What developers actually build with this provider — captured so the catalogue answers 'what is this for', not just 'what does this expose'.

What developers build with this provider.

Ecommerce Scheduling

Plan promotions, shipping cutoffs, and customer service hours around local holidays.

HR and Payroll

Populate localized leave calendars and statutory holiday pay.

Travel Planning

Surface holiday windows that affect bookings, demand, and pricing.

Workforce Scheduling

Plan global team staffing around local public holidays.

Calendar Sync

Hydrate enterprise calendars (Google, Outlook) with localized holidays.

Financial Markets

Identify country-specific trading and settlement closures.

Integrations 4

Pre-built integrations with other platforms tell you where this provider already fits in a stack.

Pre-built integrations with other platforms and tools.

Google Calendar

Imported holiday data into Google Calendar via custom calendars.

Microsoft Outlook

Hydrate Outlook calendars with localized holiday events.

Home Assistant

Community Home Assistant sensor uses Calendarific as a data source.

ETL Pipelines

Community ETL examples using Python, SQLite, and Apache Airflow.

Solutions 2

Packaged solutions the provider offers on top of the raw API surface.

Packaged solutions this provider offers.

Developer API

REST API for embedding holiday data into apps and services.

Data Downloads

CSV and XLS bulk exports for analytics and offline use.

Resources

Every other property we hold for Calendarific — 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

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Access & Security 2

Authentication, authorization, and security posture

Operate 3

Status, limits, changes, and where to get help

Company 1

The organization behind the API

← All providers · Data indexed from github.com/api-evangelist/calendarific · machine-readable index on apis.io