openapi: 3.0.1
info:
  title: Linkup API
  description: >-
    Production-grade web search and answer API for AI agents and LLMs. The
    /search endpoint grounds model responses in real-time web context, returning
    ranked results, sourced answers with inline citations, or schema-driven
    structured output. /fetch converts a URL into clean LLM-ready markdown,
    /research starts an asynchronous deep-research task, and /credits/balance
    reports remaining account credits. All endpoints authenticate with a Bearer
    API key.
  termsOfService: https://www.linkup.so/terms-of-service
  contact:
    name: Linkup
    url: https://www.linkup.so
  version: '1.0'
servers:
  - url: https://api.linkup.so/v1
security:
  - bearerAuth: []
paths:
  /search:
    post:
      operationId: search
      tags:
        - Search
      summary: Run a web search and return context for an AI agent or LLM.
      description: >-
        Runs a natural-language query against the live web at fast, standard, or
        deep precision and returns ranked search results, a sourced answer with
        optional inline citations, or schema-driven structured output.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/SearchRequest'
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SearchResponse'
        '400':
          description: Bad Request
        '401':
          description: Unauthorized
        '402':
          description: Payment Required (insufficient credits)
        '429':
          description: Too Many Requests
  /fetch:
    post:
      operationId: fetch
      tags:
        - Fetch
      summary: Fetch a URL as clean LLM-ready markdown.
      description: >-
        Retrieves the content of a given URL and returns it as clean markdown,
        with options to render JavaScript, include raw HTML, and extract images.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/FetchRequest'
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FetchResponse'
        '400':
          description: Bad Request
        '401':
          description: Unauthorized
        '402':
          description: Payment Required (insufficient credits)
        '429':
          description: Too Many Requests
  /research:
    post:
      operationId: createResearch
      tags:
        - Research
      summary: Start an asynchronous deep-research task (beta).
      description: >-
        Starts an autonomous web investigation. Returns immediately with a task
        id and a non-terminal status; poll GET /research/{id} until the task
        reaches a terminal state to retrieve the synthesized, cited result.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ResearchRequest'
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ResearchTask'
        '401':
          description: Unauthorized
        '402':
          description: Payment Required (insufficient credits)
        '429':
          description: Too Many Requests
  /research/{id}:
    get:
      operationId: getResearch
      tags:
        - Research
      summary: Retrieve the state and result of a research task.
      parameters:
        - name: id
          in: path
          required: true
          schema:
            type: string
          description: Identifier of the research task.
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ResearchTask'
        '401':
          description: Unauthorized
        '404':
          description: Not Found
        '429':
          description: Too Many Requests
  /credits/balance:
    get:
      operationId: getCreditsBalance
      tags:
        - Credits
      summary: Retrieve the remaining credits balance for the account.
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/BalanceResponse'
        '401':
          description: Unauthorized
components:
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: 'Pass your Linkup API key as `Authorization: Bearer <API_KEY>`.'
  schemas:
    SearchRequest:
      type: object
      required:
        - q
        - depth
        - outputType
      properties:
        q:
          type: string
          description: Natural-language question used to retrieve web context.
        depth:
          type: string
          enum:
            - fast
            - standard
            - deep
          description: Search precision mode.
        outputType:
          type: string
          enum:
            - searchResults
            - sourcedAnswer
            - structured
          description: Shape of the returned payload.
        structuredOutputSchema:
          type: string
          description: >-
            JSON Schema (as a string) describing the desired structured output.
            Required when outputType is `structured`.
        includeImages:
          type: boolean
          default: false
          description: Include images in the results.
        includeInlineCitations:
          type: boolean
          default: false
          description: Include inline citations. Applies only to `sourcedAnswer`.
        includeSources:
          type: boolean
          default: false
          description: Include sources. Applies only to `structured`.
        fromDate:
          type: string
          format: date
          description: Restrict results to this date forward (YYYY-MM-DD).
        toDate:
          type: string
          format: date
          description: Restrict results up to this date (YYYY-MM-DD).
        includeDomains:
          type: array
          items:
            type: string
          description: Restrict the search to these domains (max 100).
        excludeDomains:
          type: array
          items:
            type: string
          description: Exclude these domains from the search.
        maxResults:
          type: integer
          minimum: 1
          description: Maximum number of results to return.
    SearchResponse:
      type: object
      description: >-
        Shape varies by outputType. For `searchResults`, an array of results;
        for `sourcedAnswer`, an answer plus sources; for `structured`, a custom
        object optionally accompanied by sources.
      properties:
        answer:
          type: string
          description: The sourced answer (outputType `sourcedAnswer`).
        results:
          type: array
          description: Ranked search results (outputType `searchResults`).
          items:
            $ref: '#/components/schemas/SearchResult'
        sources:
          type: array
          items:
            $ref: '#/components/schemas/Source'
    SearchResult:
      type: object
      properties:
        type:
          type: string
          enum:
            - text
            - image
        name:
          type: string
        url:
          type: string
          format: uri
        content:
          type: string
    Source:
      type: object
      properties:
        name:
          type: string
        url:
          type: string
          format: uri
        snippet:
          type: string
    FetchRequest:
      type: object
      required:
        - url
      properties:
        url:
          type: string
          format: uri
          description: The URL of the webpage to fetch.
        renderJs:
          type: boolean
          default: false
          description: Whether the API should render the JavaScript of the webpage.
        includeRawHtml:
          type: boolean
          default: false
          description: Whether to include the raw HTML of the webpage in the response.
        extractImages:
          type: boolean
          default: false
          description: Whether to extract images from the webpage in the response.
    FetchResponse:
      type: object
      required:
        - markdown
      properties:
        markdown:
          type: string
          description: The webpage content as clean markdown.
        rawHtml:
          type: string
          description: The raw HTML of the webpage (when includeRawHtml is true).
        images:
          type: array
          items:
            type: object
            required:
              - alt
              - url
            properties:
              alt:
                type: string
              url:
                type: string
                format: uri
    ResearchRequest:
      type: object
      required:
        - query
      properties:
        query:
          type: string
          description: Natural-language research question.
        mode:
          type: string
          enum:
            - answer
            - investigate
            - research
          description: >-
            Type of investigation. Omit to let Linkup classify the question.
        reasoningDepth:
          type: string
          enum:
            - S
            - M
            - L
            - XL
          default: L
          description: How much reasoning effort the task spends.
    ResearchTask:
      type: object
      properties:
        id:
          type: string
          description: Identifier of the research task.
        status:
          type: string
          enum:
            - pending
            - processing
            - completed
            - failed
          description: Current state of the task.
        output:
          type: object
          description: The synthesized, cited result when status is `completed`.
        error:
          type: string
          description: Failure reason when status is `failed`.
    BalanceResponse:
      type: object
      properties:
        balance:
          type: number
          description: The number of credits remaining in your account.
          example: 123.456