fourzerotwo-si

fourzerotwo-si Crossref API

Crossref DOI Metadata: Resolve DOIs to bibliographic metadata and search scholarly works, journals and funders.

GitHub OpenAPI

Operations 5

GET /v1/crossref/doi Crossref DOI Metadata: DOI lookup #
GET /v1/crossref/search Crossref DOI Metadata: Search works #
GET /v1/crossref/journal Crossref DOI Metadata: Journal by ISSN #
GET /v1/crossref/funders Crossref DOI Metadata: Search funders #
GET /v1/crossref/members Crossref DOI Metadata: Search publishers #

Specifications

⚙
OpenAPI
https://artifacts.apis.io/fourzerotwo-si/openapi/fourzerotwo-si-crossref-api-openapi.yml

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OpenAPI Specification

fourzerotwo-si-crossref-api-openapi.yml Raw ↑ 
openapi: 3.2.0
info:
  title: Fourzerotwo Si Crossref API
  version: 1.1.0
  contact:
    url: https://fourzerotwo.si
  description: 'Operations tagged crossref across 2 of this provider''s published API definitions: openapi.json, fourzerotwo-si-openapi.json. Each path carries the servers of the definition it was published in.'
servers:
- url: https://fourzerotwo.si
tags:
- name: crossref
  description: 'Crossref DOI Metadata: Resolve DOIs to bibliographic metadata and search scholarly works, journals and funders.'
paths:
  /v1/crossref/doi:
    get:
      operationId: crossref__doi
      summary: 'Crossref DOI Metadata: DOI lookup'
      description: 'Title, authors, journal, dates, references count and licence for a DOI. Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - crossref
      externalDocs:
        url: https://fourzerotwo.si/apis/crossref/doi
      parameters:
      - name: doi
        in: query
        required: true
        description: DOI
        schema:
          type: string
        example: 10.1038/nature14539
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: crossref__doi
    servers:
    - url: https://fourzerotwo.si
  /v1/crossref/search:
    get:
      operationId: crossref__search
      summary: 'Crossref DOI Metadata: Search works'
      description: 'Bibliographic search across Crossref works. Price: $0.003 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - crossref
      externalDocs:
        url: https://fourzerotwo.si/apis/crossref/search
      parameters:
      - name: q
        in: query
        required: true
        description: Query
        schema:
          type: string
        example: deep learning review
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.003000'
      x-free-tier: free
      x-mcp-tool: crossref__search
    servers:
    - url: https://fourzerotwo.si
  /v1/crossref/journal:
    get:
      operationId: crossref__journal
      summary: 'Crossref DOI Metadata: Journal by ISSN'
      description: 'Journal title, publisher and DOI counts by ISSN. Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - crossref
      externalDocs:
        url: https://fourzerotwo.si/apis/crossref/journal
      parameters:
      - name: issn
        in: query
        required: true
        description: ISSN
        schema:
          type: string
        example: 0028-0836
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: crossref__journal
    servers:
    - url: https://fourzerotwo.si
  /v1/crossref/funders:
    get:
      operationId: crossref__funders
      summary: 'Crossref DOI Metadata: Search funders'
      description: 'Research funders by name, with Funder Registry ids. Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - crossref
      externalDocs:
        url: https://fourzerotwo.si/apis/crossref/funders
      parameters:
      - name: q
        in: query
        required: true
        description: Funder
        schema:
          type: string
        example: Wellcome
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: crossref__funders
    servers:
    - url: https://fourzerotwo.si
  /v1/crossref/members:
    get:
      operationId: crossref__members
      summary: 'Crossref DOI Metadata: Search publishers'
      description: 'Crossref member publishers by name. Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - crossref
      externalDocs:
        url: https://fourzerotwo.si/apis/crossref/members
      parameters:
      - name: q
        in: query
        required: true
        description: Publisher
        schema:
          type: string
        example: Elsevier
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: crossref__members
    servers:
    - url: https://fourzerotwo.si
components:
  responses:
    PaymentRequired:
      description: x402 payment required. The body (also base64 in the PAYMENT-REQUIRED header) lists accepted payments.
      headers:
        PAYMENT-REQUIRED:
          schema:
            type: string
          description: Base64 JSON x402 v2 PaymentRequired
      content:
        application/json:
          schema:
            type: object
            properties:
              x402Version:
                type: integer
              error:
                type: string
              accepts:
                type: array
                items:
                  type: object
    Error:
      description: 400 = invalid input, 404 = not found at the source, 502 = the source failed. Never charged.
      content:
        application/json:
          schema:
            type: object
            properties:
              error:
                type: string
              charged:
                type: boolean
  securitySchemes:
    freeKey:
      type: apiKey
      in: header
      name: X-API-Key
      description: Optional free key (fzt_…) for the free tier.
x-refined-from:
- openapi.json
- fourzerotwo-si-openapi.json