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OpenAPI Specification

openapi: 3.2.0
info:
  title: Fourzerotwo Si Seo API
  version: 1.1.0
  contact:
    url: https://fourzerotwo.si
  description: 'Operations tagged seo 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: SEO
  description: 'SEO Tools: On-page SEO audit of any URL, link extraction, robots.txt rules for any crawler, and keyword intent.'
paths:
  /v1/seo/robots-check:
    get:
      operationId: seo__robots_check
      summary: 'SEO Tools: robots.txt check'
      description: 'Whether a crawler (Googlebot, GPTBot, ClaudeBot…) may fetch a URL, the rule that decided it, and declared sitemaps. Price: $0.002 USDC per call via x402. 3 free calls/day with a free key.'
      tags:
      - SEO
      externalDocs:
        url: https://fourzerotwo.si/apis/seo/robots-check
      parameters:
      - name: url
        in: query
        required: true
        description: URL
        schema:
          type: string
          maxLength: 2000
        example: https://www.bbc.co.uk/news
      - name: user_agent
        in: query
        required: false
        description: Crawler user agent
        schema:
          type: string
        example: GPTBot
      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: sample
      x-mcp-tool: seo__robots-check
    servers:
    - url: https://fourzerotwo.si
  /v1/seo/page-audit:
    get:
      operationId: seo__page_audit
      summary: 'SEO Tools: On-page SEO audit'
      description: 'Title, meta, H1, canonical, noindex, hreflang, structured data, OG tags, word count, links, alt text, issues and a score. Price: $0.005 USDC per call via x402. 3 free calls/day with a free key.'
      tags:
      - SEO
      externalDocs:
        url: https://fourzerotwo.si/apis/seo/page-audit
      parameters:
      - name: url
        in: query
        required: true
        description: Page URL
        schema:
          type: string
          maxLength: 2000
        example: https://www.gov.uk/vehicle-tax-rate-tables
      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: '0.005000'
      x-free-tier: sample
      x-mcp-tool: seo__page-audit
    servers:
    - url: https://fourzerotwo.si
  /v1/seo/links:
    get:
      operationId: seo__links
      summary: 'SEO Tools: Extract links'
      description: 'Internal and external links on a page with anchor text and nofollow flags. Price: $0.003 USDC per call via x402. 3 free calls/day with a free key.'
      tags:
      - SEO
      externalDocs:
        url: https://fourzerotwo.si/apis/seo/links
      parameters:
      - name: url
        in: query
        required: true
        description: Page URL
        schema:
          type: string
          maxLength: 2000
        example: https://fourzerotwo.si
      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: sample
      x-mcp-tool: seo__links
    servers:
    - url: https://fourzerotwo.si
  /v1/seo/keyword-intent:
    get:
      operationId: seo__keyword_intent
      summary: 'SEO Tools: Keyword intent'
      description: 'Classify a search keyword as transactional, commercial, navigational or informational. Price: $0.0005 USDC per call via x402. 3 free calls/day with a free key.'
      tags:
      - SEO
      externalDocs:
        url: https://fourzerotwo.si/apis/seo/keyword-intent
      parameters:
      - name: keyword
        in: query
        required: true
        description: Keyword
        schema:
          type: string
          maxLength: 200
        example: best car history check uk
      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: '0.000500'
      x-free-tier: sample
      x-mcp-tool: seo__keyword-intent
    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