Crossref

Crossref is a non-profit organization that provides digital infrastructure for scholarly communications. Best known for Digital Object Identifier (DOI) registration, Crossref also operates a public REST API offering searchable, filterable access to metadata for tens of millions of scholarly works, journals, members, funders, prefixes, types, licenses, and DOI registration agency information. The Crossref REST API supports free-form queries, field queries, filters, facets, deep-paging cursors, and selection of specific elements, and is used by reference managers, repositories, discovery layers, and analytics platforms.

Crossref publishes 8 APIs on the APIs.io network, including Agency API, Funders API, Journals API, and 5 more. Tagged areas include Citations, DOI, Funders, Identifiers, and Journals.

The Crossref catalog on APIs.io includes 1 JSON-LD context and 2 Spectral governance rulesets.

Crossref’s developer surface includes documentation, engineering blog, and 14 more developer resources.

🌐 Visit website 📡 Source on GitHub

31.6/100 thin ▬ flat Agent 20/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessFreemium

1 APIs

Citations DOI Funders Identifiers Journals Licenses Members Metadata Open Access ORCID Prefixes PublishersReference LinkingROR Scholarly

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 31.6/100 · thin

Contract Quality 11.0 / 21

Developer Ergonomics 3.6 / 17

Access Clarity 0.0 / 17

Operational Transparency 2.9 / 11

Contract Governance 2.9 / 10

Discoverability 5.8 / 9

Regulatory Posture 4.7 / 15

Agent readiness — 20/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 9 / 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

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 4 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Education & Research 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 does not apply to this provider. The published contracts declare no write operations, and a read-only API cannot create-or-update. The facet is excluded from this provider's denominator entirely — not scored zero. A reference or data API is not deficient for being unable to upsert.

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/. 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 github.com/api-evangelist/crossref: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 8

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

Crossref Agency API

The Agency API from Crossref — 1 operation(s) for agency.

Crossref Funders API

Endpoints that expose funder related data

Crossref Journals API

Endpoints that expose journal related data

Crossref Licenses API

Endpoints that expose license related data

Crossref Members API

Endpoints that expose member related data

Crossref Prefixes API

Endpoints that expose prefix related data

Crossref Types API

Endpoints that expose type related data

Crossref Works API

Endpoints that expose works related data

Scroll for all 8

Open Collections 10

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

API Collection

OPEN COLLECTION

Crossref Agency API

OPEN COLLECTION

Crossref Agency Funders API

OPEN COLLECTION

Crossref Agency Journals API

OPEN COLLECTION

Crossref Agency Licenses API

OPEN COLLECTION

Crossref Agency Members API

OPEN COLLECTION

Crossref Agency Prefixes API

OPEN COLLECTION

Crossref Agency Types API

OPEN COLLECTION

Crossref Agency Works API

OPEN COLLECTION

Crossref

OPEN COLLECTION

Scroll for all 10

Pricing Plans 1

Published pricing tiers and plan structures.

Crossref Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Crossref Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Crossref Finops

FINOPS

Semantic Vocabularies 1

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

Crossref Context

36 classes · 12 properties

JSON-LD

Spectral Rules 2

Spectral governance rulesets for linting and validating these APIs.

Crossref API Rules

6 rules · 4 warnings 2 info

SPECTRAL

Crossref API Rules

6 rules · 5 errors 1 warnings

SPECTRAL

JSON Schema 1

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

Crossref Work

38 properties

JSON SCHEMA

Security Posture 2

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

Crossref Domain Security

TLSv1.3 · DMARC

SECURITY

Crossref Vulnerability Disclosure

security.txt · contact published

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Crossref Agentic Access

18 operations

18 operations · 0 acting

AGENTIC

Resources

Documentation 3

Reference material describing how the API behaves

JSONSchema

JSONSchema

Documentation

Documentation

APIDocumentation

APIDocumentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Vocabulary

Vocabulary

JSONLD

JSONLD

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

StatusPage

StatusPage

Community

Community

Commercial 1

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

Company 3

The organization behind the API

LinkedIn

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

CapabilityMap

CapabilityMap

Source (apis.yml)

aid: crossref
name: Crossref
kind: company
description: Crossref is a non-profit organization that provides digital infrastructure for scholarly communications. Best
  known for Digital Object Identifier (DOI) registration, Crossref also operates a public REST API offering searchable, filterable
  access to metadata for tens of millions of scholarly works, journals, members, funders, prefixes, types, licenses, and DOI
  registration agency information. The Crossref REST API supports free-form queries, field queries, filters, facets, deep-paging
  cursors, and selection of specific elements, and is used by reference managers, repositories, discovery layers, and analytics
  platforms.
url: https://raw.githubusercontent.com/api-evangelist/crossref/refs/heads/main/apis.yml
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/crossref.png
tags:
- Citations
- DOI
- Funders
- Identifiers
- Journals
- Licenses
- Members
- Metadata
- Open Access
- ORCID
- Prefixes
- Publishers
- Reference Linking
- ROR
- Scholarly
created: '2024-07-02'
modified: '2026-05-19'
specificationVersion: '0.23'
type: Index
access: Public
position: Producing
apis:
- aid: crossref:crossref-agency-api
  name: Crossref Agency API
  description: The Agency API from Crossref — 1 operation(s) for agency.
  humanURL: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  baseURL: https://api.crossref.org
  tags:
  - Agency
  properties:
  - type: OpenAPI
    url: openapi/crossref-agency-api-openapi.yml
  - type: Documentation
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  - type: SwaggerUI
    url: https://api.crossref.org/swagger-ui/
  - type: PolitePool
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/#etiquette
  - type: Tips
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/
  - type: Rules
    url: rules/crossref-rules.yml
  - type: JSONSchema
    url: json-schema/crossref-work-schema.json
  - type: JSONLD
    url: json-ld/crossref-context.jsonld
- aid: crossref:crossref-funders-api
  name: Crossref Funders API
  description: Endpoints that expose funder related data
  humanURL: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  baseURL: https://api.crossref.org
  tags:
  - Funders
  properties:
  - type: OpenAPI
    url: openapi/crossref-funders-api-openapi.yml
  - type: Documentation
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  - type: SwaggerUI
    url: https://api.crossref.org/swagger-ui/
  - type: PolitePool
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/#etiquette
  - type: Tips
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/
  - type: Rules
    url: rules/crossref-rules.yml
  - type: JSONSchema
    url: json-schema/crossref-work-schema.json
  - type: JSONLD
    url: json-ld/crossref-context.jsonld
- aid: crossref:crossref-journals-api
  name: Crossref Journals API
  description: Endpoints that expose journal related data
  humanURL: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  baseURL: https://api.crossref.org
  tags:
  - Journals
  properties:
  - type: OpenAPI
    url: openapi/crossref-journals-api-openapi.yml
  - type: Documentation
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  - type: SwaggerUI
    url: https://api.crossref.org/swagger-ui/
  - type: PolitePool
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/#etiquette
  - type: Tips
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/
  - type: Rules
    url: rules/crossref-rules.yml
  - type: JSONSchema
    url: json-schema/crossref-work-schema.json
  - type: JSONLD
    url: json-ld/crossref-context.jsonld
- aid: crossref:crossref-licenses-api
  name: Crossref Licenses API
  description: Endpoints that expose license related data
  humanURL: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  baseURL: https://api.crossref.org
  tags:
  - Licenses
  properties:
  - type: OpenAPI
    url: openapi/crossref-licenses-api-openapi.yml
  - type: Documentation
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  - type: SwaggerUI
    url: https://api.crossref.org/swagger-ui/
  - type: PolitePool
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/#etiquette
  - type: Tips
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/
  - type: Rules
    url: rules/crossref-rules.yml
  - type: JSONSchema
    url: json-schema/crossref-work-schema.json
  - type: JSONLD
    url: json-ld/crossref-context.jsonld
- aid: crossref:crossref-members-api
  name: Crossref Members API
  description: Endpoints that expose member related data
  humanURL: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  baseURL: https://api.crossref.org
  tags:
  - Members
  properties:
  - type: OpenAPI
    url: openapi/crossref-members-api-openapi.yml
  - type: Documentation
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  - type: SwaggerUI
    url: https://api.crossref.org/swagger-ui/
  - type: PolitePool
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/#etiquette
  - type: Tips
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/
  - type: Rules
    url: rules/crossref-rules.yml
  - type: JSONSchema
    url: json-schema/crossref-work-schema.json
  - type: JSONLD
    url: json-ld/crossref-context.jsonld
- aid: crossref:crossref-prefixes-api
  name: Crossref Prefixes API
  description: Endpoints that expose prefix related data
  humanURL: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  baseURL: https://api.crossref.org
  tags:
  - Prefixes
  properties:
  - type: OpenAPI
    url: openapi/crossref-prefixes-api-openapi.yml
  - type: Documentation
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  - type: SwaggerUI
    url: https://api.crossref.org/swagger-ui/
  - type: PolitePool
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/#etiquette
  - type: Tips
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/
  - type: Rules
    url: rules/crossref-rules.yml
  - type: JSONSchema
    url: json-schema/crossref-work-schema.json
  - type: JSONLD
    url: json-ld/crossref-context.jsonld
- aid: crossref:crossref-types-api
  name: Crossref Types API
  description: Endpoints that expose type related data
  humanURL: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  baseURL: https://api.crossref.org
  tags:
  - Types
  properties:
  - type: OpenAPI
    url: openapi/crossref-types-api-openapi.yml
  - type: Documentation
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  - type: SwaggerUI
    url: https://api.crossref.org/swagger-ui/
  - type: PolitePool
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/#etiquette
  - type: Tips
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/
  - type: Rules
    url: rules/crossref-rules.yml
  - type: JSONSchema
    url: json-schema/crossref-work-schema.json
  - type: JSONLD
    url: json-ld/crossref-context.jsonld
- aid: crossref:crossref-works-api
  name: Crossref Works API
  description: Endpoints that expose works related data
  humanURL: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  baseURL: https://api.crossref.org
  tags:
  - Works
  properties:
  - type: OpenAPI
    url: openapi/crossref-works-api-openapi.yml
  - type: Documentation
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
  - type: SwaggerUI
    url: https://api.crossref.org/swagger-ui/
  - type: PolitePool
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/#etiquette
  - type: Tips
    url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/
  - type: Rules
    url: rules/crossref-rules.yml
  - type: JSONSchema
    url: json-schema/crossref-work-schema.json
  - type: JSONLD
    url: json-ld/crossref-context.jsonld
common:
- type: CapabilityMap
  url: capabilities/crossref-capability-edges.yml
  name: Crossref Business Capability Map
- type: AgenticAccess
  url: agentic-access/crossref-agentic-access.yml
- type: VulnerabilityDisclosure
  url: security/crossref-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/crossref-domain-security.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/crossref
- type: Vocabulary
  url: vocabulary/crossref-vocabulary.yml
- type: JSONLD
  url: json-ld/crossref-context.jsonld
- type: JSONSchema
  url: json-schema/crossref-work-schema.json
- type: Website
  url: https://www.crossref.org/
- type: Documentation
  url: https://www.crossref.org/documentation/
- type: APIDocumentation
  url: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
- type: Blog
  url: https://www.crossref.org/blog/
- type: GitHubOrganization
  url: https://github.com/CrossRef
- type: StatusPage
  url: https://status.crossref.org/
- type: Community
  url: https://community.crossref.org/
- type: TermsOfService
  url: https://www.crossref.org/operations-and-sustainability/terms/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

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