> ## Documentation Index
> Fetch the complete documentation index at: https://docs.surnex.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Link gap between domains

> Referring domains that link to the competitors but not to the target.



## OpenAPI

````yaml https://api.surnex.io/docs/openapi.json post /v1/backlinks/gap
openapi: 3.1.0
info:
  title: Surnex API
  version: 1.0.0
  description: >-
    The SEO platform's API.


    **The API is the product.** The dashboard is one client and the MCP server
    at `/mcp` is another. If a number needs deriving, a service derives it —
    never a React component, or the two clients drift.


    **Two kinds of auth.** The dashboard sends a Supabase access token as a
    Bearer JWT. MCP agents send `X-API-Key`, and the organization is resolved
    from the key.


    **Two data modes.** SERP results and Google Trends are fetched live on
    request. Everything else is written by the worker and read from Postgres, so
    a freshly-created project returns empty until its jobs complete.
servers:
  - url: https://api.surnex.io
    description: Surnex API
security: []
paths:
  /v1/backlinks/gap:
    post:
      tags:
        - backlinks
      summary: Link gap between domains
      description: Referring domains that link to the competitors but not to the target.
      parameters:
        - schema:
            type: string
            format: uuid
          required: false
          name: org_id
          in: query
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                target_domain:
                  type: string
                  minLength: 1
                competitor_domains:
                  type: array
                  items:
                    type: string
                    minLength: 1
                  minItems: 1
                  maxItems: 20
                limit:
                  type: integer
                  minimum: 1
                  maximum: 1000
                  default: 100
              required:
                - target_domain
                - competitor_domains
      responses:
        '200':
          description: Opportunities
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    enum:
                      - true
                  data:
                    type: object
                    nullable: true
                    properties:
                      data:
                        type: array
                        items:
                          nullable: true
                      cached:
                        type: boolean
                    required:
                      - data
                      - cached
                required:
                  - success
                  - data
        '402':
          description: No research lookups left this month, or no active plan
          content:
            application/json:
              schema:
                type: object
                properties: {}

````

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