APIs.io Synthesis API

openapi: 3.1.0
info:
  title: .io Search APIs Synthesis API
  description: This is the technical API contract for the search API for the APIs.io search engine.
  version: 0.1.0
  contact:
    name: Kin Lane
    email: info@apievangelist.com
servers:
- url: https://search-api.apis.io
tags:
- name: Synthesis
  description: Decision-grade composites over the catalog — provider comparison, gap analysis, catalog change feed, and recommended-stack design. Pro.
paths:
  /compare:
    get:
      operationId: compareProviders
      x-tier: pro
      x-mcp-tool: compare_providers
      security: []
      tags:
      - Synthesis
      summary: Compare providers side by side (Pro).
      description: Compares 2+ providers — composite/band, per-facet leaders, and an artifact-coverage matrix. Pro tier.
      parameters:
      - name: providers
        in: query
        required: true
        description: Comma-separated provider slugs to compare (2+).
        schema:
          type: string
          maxLength: 1024
      responses:
        '200':
          description: Side-by-side comparison of the requested providers.
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '400':
          $ref: '#/components/responses/BadRequest'
        '403':
          $ref: '#/components/responses/UpgradeRequired'
  /gaps:
    get:
      operationId: gapAnalysis
      x-tier: pro
      x-mcp-tool: gap_analysis
      security: []
      tags:
      - Synthesis
      summary: Artifact + score gap analysis for a provider or stack (Pro).
      description: For each provider — the high-value artifacts it lacks, what its peers commonly publish but it lacks, and its score vs the peer median — plus stack-level gaps across the set. Pro tier.
      parameters:
      - name: providers
        in: query
        required: true
        description: Comma-separated provider slugs (1+). Multiple = treat as a stack.
        schema:
          type: string
          maxLength: 1024
      - name: min_share
        in: query
        description: Peer-share threshold for a gap (0–1, default 0.25).
        schema:
          type: number
          maximum: 1000000000
      responses:
        '200':
          description: Per-provider and stack-level gaps.
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '400':
          $ref: '#/components/responses/BadRequest'
        '403':
          $ref: '#/components/responses/UpgradeRequired'
  /changes:
    get:
      operationId: whatsChanged
      x-tier: pro
      x-mcp-tool: whats_changed
      security: []
      tags:
      - Synthesis
      summary: What changed in the catalog since a date (Pro).
      description: Providers added/updated since a date, plus rating movement (up/down) from the latest scoring build. Pro tier.
      parameters:
      - name: since
        in: query
        required: true
        description: Cutoff date, YYYY-MM-DD.
        schema:
          type: string
          format: date
          maxLength: 10
      - $ref: '#/components/parameters/Limit'
      responses:
        '200':
          description: Catalog changes since the given date.
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '400':
          $ref: '#/components/responses/BadRequest'
        '403':
          $ref: '#/components/responses/UpgradeRequired'
  /stack:
    get:
      operationId: recommendStack
      x-tier: free
      x-mcp-tool: recommend_stack
      x-agent-skill: assemble-api-stack
      tags:
      - Synthesis
      summary: Design a recommended API stack per capability.
      description: Decompose a domain into capabilities, then get the best-rated catalog provider per capability assembled into a stack. FREE returns a preview (top pick per capability); PRO returns alternatives, per-pick artifact gaps, and an exportable APIs.json + Arazzo hint.
      parameters:
      - name: capabilities
        in: query
        required: true
        description: Comma-separated capabilities the stack needs, e.g. `payments,email,identity,observability`.
        schema:
          type: string
          maxLength: 1024
      - name: region
        in: query
        description: Optional region slug to prefer, e.g. `europe`.
        schema:
          type: string
          maxLength: 1024
      responses:
        '200':
          description: A recommended stack (preview for free callers; full for Pro).
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '400':
          $ref: '#/components/responses/BadRequest'
      security: []
  /gaps/industry/{slug}:
    get:
      operationId: industryGapAnalysis
      x-tier: pro
      x-mcp-tool: industry_gap_analysis
      x-agent-skill: audit-api-estate
      security: []
      tags:
      - Synthesis
      summary: Artifact gaps across a whole industry.
      description: For an industry vertical, reports which valuable artifact types (MCP, Arazzo, Rules, Skills…) most member providers lack — where the vertical is under-served.
      parameters:
      - name: slug
        in: path
        required: true
        description: Industry slug (e.g. `financial-services`).
        schema:
          type: string
          maxLength: 1024
      - name: min_share
        in: query
        description: Coverage threshold below which a type counts as an industry gap (0–1, default 0.5).
        schema:
          type: number
          maximum: 1000000000
      responses:
        '200':
          description: The industry's valuable-artifact coverage and gaps.
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '404':
          $ref: '#/components/responses/NotFound'
  /stack/export:
    get:
      operationId: exportStack
      x-tier: pro
      x-mcp-tool: export_stack
      x-agent-skill: assemble-api-stack
      security: []
      tags:
      - Synthesis
      summary: Export a designed stack as APIs.json.
      description: Given a set of capabilities, returns the designed stack as an adoptable APIs.json document (with an Arazzo hint) the team can commit.
      parameters:
      - name: capabilities
        in: query
        required: true
        description: Comma-separated capabilities the stack needs, e.g. `payments,email,identity`.
        schema:
          type: string
          maxLength: 1024
      - name: region
        in: query
        description: Optional region slug to prefer.
        schema:
          type: string
          maxLength: 1024
      responses:
        '200':
          description: The exportable stack.
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '400':
          $ref: '#/components/responses/BadRequest'
components:
  parameters:
    Limit:
      name: limit
      in: query
      description: Items per page.
      schema:
        type: integer
        minimum: 1
        maximum: 100
        default: 25
  responses:
    BadRequest:
      description: Malformed request (bad parameter value).
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            type: https://apis.io/problems/invalid-parameter
            title: Invalid parameter
            status: 400
            detail: '`match` must be one of: any, all.'
            instance: /v1/search
            parameter: match
    NotFound:
      description: Resource not found.
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            type: https://apis.io/problems/not-found
            title: Resource not found
            status: 404
            detail: No API found with aid `twilio:nope`.
            instance: /v1/apis/twilio:nope
    UpgradeRequired:
      description: This operation requires the Pro tier. Send a valid `X-API-Key` for a paid tier.
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            type: https://apis.io/problems/upgrade-required
            title: Upgrade required
            status: 403
            detail: The areas endpoint requires the Pro or Business tier.
            instance: /v1/areas
  schemas:
    Problem:
      type: object
      description: 'A Problem Details object per [RFC 9457](https://www.rfc-editor.org/rfc/rfc9457).

        Served as `application/problem+json`. Extension members (e.g. `parameter`) may be

        added alongside the standard fields.

        '
      properties:
        type:
          type: string
          format: uri
          default: about:blank
          description: A URI identifying the problem type; dereferences to human-readable docs.
          examples:
          - https://apis.io/problems/invalid-parameter
          maxLength: 2048
        title:
          type: string
          description: A short, human-readable summary of the problem type.
          examples:
          - Invalid parameter
          maxLength: 1024
        status:
          type: integer
          minimum: 100
          maximum: 599
          description: The HTTP status code, repeated for convenience.
          examples:
          - 400
        detail:
          type: string
          description: A human-readable explanation specific to this occurrence.
          maxLength: 20000
        instance:
          type: string
          format: uri-reference
          description: A URI reference identifying the specific occurrence (typically the request path).
          maxLength: 2048
        parameter:
          type: string
          description: Extension member — the offending query/path parameter, when applicable.
          maxLength: 1024
      required:
      - type
      - title
      - status
      additionalProperties: true
  securitySchemes:
    api_key:
      type: apiKey
      name: x-api-key
      in: header