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

# Estimate broadcast audience

> Estimate the number of contacts matching an audience filter.



## OpenAPI

````yaml /api-reference/openapi.json post /api/broadcasts/estimate
openapi: 3.1.0
info:
  title: Tedro API
  version: 1.0.0
  description: REST API for the Tedro communication operations platform.
servers:
  - url: https://api.tedro.io
    description: Production
security:
  - sessionCookie: []
    workspaceId: []
paths:
  /api/broadcasts/estimate:
    post:
      tags:
        - Broadcasts
      summary: Estimate broadcast audience
      description: Estimate the number of contacts matching an audience filter.
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/EstimateAudience'
      responses:
        '200':
          description: Audience estimate
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AudienceEstimateResponse'
        '401':
          description: Unauthorized - missing or invalid session cookie
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '404':
          description: Not Found - resource does not exist or belongs to another tenant
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '500':
          description: Internal Server Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
      security:
        - sessionCookie: []
          workspaceId: []
components:
  schemas:
    EstimateAudience:
      type: object
      properties:
        audienceFilter: {}
        groupId:
          type: string
          format: uuid
      additionalProperties: false
      description: Estimate broadcast audience count
      example:
        groupId: 550e8400-e29b-41d4-a716-446655440000
    AudienceEstimateResponse:
      type: object
      properties:
        count:
          type: number
      required:
        - count
    ErrorResponse:
      type: object
      properties:
        error:
          type: string
      required:
        - error
  securitySchemes:
    sessionCookie:
      type: apiKey
      in: cookie
      name: better-auth.session_token
      description: Session cookie set by Better Auth on sign-in.
    workspaceId:
      type: apiKey
      in: header
      name: x-workspace-id
      description: Workspace UUID. Required on all /api/* endpoints.

````