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

# Create measurement source

> Register a measurement data source (e.g. MMM, brand lift study) for an advertiser.



## OpenAPI

````yaml /v2/buyer-api-v2.yaml post /advertisers/{advertiserId}/measurement-sources
openapi: 3.0.0
info:
  title: Scope3 Buyer API
  version: 2.0.0
  description: |-
    REST API for advertisers to manage advertisers, campaigns, and reporting.

    ## Authentication

    All endpoints require a Bearer token in the Authorization header:
    ```
    Authorization: Bearer your-api-key
    ```

    ## Base URL

    `https://api.interchange.io/api/v2/buyer`

    ## For AI Agents

    AI agents can use the MCP endpoint at `/mcp/v2/buyer` with three tools:
    - `initialize`: Start an MCP session
    - `api_call`: Make REST API calls
    - `ask_about_capability`: Learn about API features
servers:
  - url: https://api.interchange.io/api/v2/buyer
    description: Production server
security: []
tags:
  - name: Signup
    description: Request reviewed access to Interchange
  - name: Account
    description: Account management, service tokens, and preferences
  - name: Asks
    description: >-
      What you are waiting on Scope3 for — support, product, and supply asks in
      one list
  - name: Advertisers
    description: Manage advertisers
  - name: Product Discovery
    description: Discover and select products
  - name: Campaigns
    description: Manage advertising campaigns
  - name: Creatives
    description: Build, manage, and sync campaign creatives via AdCP Creative Protocol
  - name: Reporting
    description: Access performance metrics
  - name: Event Sources
    description: >-
      Manage event source configurations and log conversion/marketing events for
      attribution
  - name: Property Lists
    description: Validate property lists against AAO registry
  - name: Sales Agents
    description: View and connect sales agents
  - name: Measurement
    description: Measurement sources, records, context, and freshness
  - name: Syndication
    description: Syndicate resources to ADCP agents
  - name: Tasks
    description: Track async operation status
  - name: Buyer Billing
    description: >-
      Consolidated invoicing for buyers — invoices and pending invoice items
      issued by Scope3 across the buyer customer.
  - name: MCP
    description: Model Context Protocol endpoints for AI agents
paths:
  /advertisers/{advertiserId}/measurement-sources:
    post:
      tags:
        - Measurement
      summary: Create measurement source
      description: >-
        Register a measurement data source (e.g. MMM, brand lift study) for an
        advertiser.
      operationId: createMeasurementSource
      parameters:
        - in: path
          name: advertiserId
          schema:
            description: Unique identifier for the advertiser
            example: '12345'
            type: string
            minLength: 1
          required: true
          description: Unique identifier for the advertiser
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                sourceKey:
                  type: string
                  minLength: 1
                name:
                  type: string
                  minLength: 1
                outcomeType:
                  type: string
                  minLength: 1
                outcomeTypes:
                  type: array
                  items:
                    type: string
                granularity:
                  type: string
                  minLength: 1
                lagWeeks:
                  default: 1
                  type: integer
                  minimum: 0
                  maximum: 9007199254740991
                cadence:
                  type: string
                  enum:
                    - continuous
                    - daily
                    - weekly
                    - biweekly
                    - monthly
                    - quarterly
                provider:
                  type: string
                  minLength: 1
                ingestionMethod:
                  type: string
                attributionConfig:
                  type: object
                  additionalProperties: {}
                signalWeight:
                  default: 1
                  type: number
                  minimum: 0
                  maximum: 1
                status:
                  default: pending
                  type: string
                  enum:
                    - pending
                    - active
                    - paused
                notes:
                  type: string
              required:
                - sourceKey
                - name
                - outcomeType
                - granularity
                - cadence
                - provider
      responses:
        '201':
          description: Create measurement source
        '400':
          description: Bad request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '401':
          description: Unauthorized
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '500':
          description: Internal server error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
      security:
        - bearerAuth: []
components:
  schemas:
    ErrorResponse:
      description: Standard error response
      type: object
      properties:
        data:
          type: string
          nullable: true
          enum:
            - null
        error:
          $ref: '#/components/schemas/ApiError'
      required:
        - data
        - error
      additionalProperties: false
    ApiError:
      description: Structured error object
      type: object
      properties:
        code:
          description: Machine-readable error code
          type: string
        message:
          description: Human-readable error message
          type: string
        field:
          description: Field path associated with the error
          type: string
        details:
          description: Additional error context
          type: object
          additionalProperties: {}
      required:
        - code
        - message
      additionalProperties: false
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: API key or access token

````