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

# Add Contacts to Audience

> Adds one or more contacts to an audience by their IDs. Audiences are reusable and may be attached to multiple campaigns; adding a contact here enrolls them in every campaign that uses this audience. To target a single campaign, create a new audience for the contact (create_audience) and attach it to that campaign instead of editing an existing shared one.



## OpenAPI

````yaml https://api.monaco.com/openapi.json post /v1/audiences/{audience_id}/contacts
openapi: 3.1.0
info:
  title: Monaco Public API
  description: Public API for Monaco
  version: 1.0.0
servers:
  - url: https://api.monaco.com
security: []
paths:
  /v1/audiences/{audience_id}/contacts:
    post:
      tags:
        - Audiences
      summary: Add Contacts to Audience
      description: >-
        Adds one or more contacts to an audience by their IDs. Audiences are
        reusable and may be attached to multiple campaigns; adding a contact
        here enrolls them in every campaign that uses this audience. To target a
        single campaign, create a new audience for the contact (create_audience)
        and attach it to that campaign instead of editing an existing shared
        one.
      operationId: add_contacts_to_audience
      parameters:
        - name: audience_id
          in: path
          required: true
          schema:
            type: string
            format: uuid
            title: Audience Id
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/AudienceContactsRequest'
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                $ref: >-
                  #/components/schemas/PublicItemResponse_AudienceContactsResponse_
              example:
                data:
                  audience_id: aud_abc123
                  failures: []
                meta:
                  timestamp: '2026-05-11T10:30:00Z'
        4XX:
          description: Client error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/PublicErrorResponse'
components:
  schemas:
    AudienceContactsRequest:
      properties:
        contact_ids:
          items:
            type: string
            format: uuid
          type: array
          maxItems: 10000
          minItems: 1
          title: Contact Ids
          description: IDs of the contacts to add or remove
      type: object
      required:
        - contact_ids
      title: AudienceContactsRequest
    PublicItemResponse_AudienceContactsResponse_:
      properties:
        data:
          $ref: '#/components/schemas/AudienceContactsResponse'
        meta:
          $ref: '#/components/schemas/ResponseMeta'
      type: object
      required:
        - data
      title: PublicItemResponse[AudienceContactsResponse]
    PublicErrorResponse:
      properties:
        error:
          $ref: '#/components/schemas/ErrorDetail'
      type: object
      required:
        - error
      title: PublicErrorResponse
    AudienceContactsResponse:
      properties:
        audience_id:
          type: string
          title: Audience Id
          description: ID of the audience that was modified
        failures:
          items:
            $ref: '#/components/schemas/AudienceContactFailureGroup'
          type: array
          title: Failures
          description: >-
            Contacts that exist but could not be added or removed, grouped by
            reason
      type: object
      required:
        - audience_id
      title: AudienceContactsResponse
    ResponseMeta:
      properties:
        timestamp:
          type: string
          format: date-time
          title: Timestamp
          description: Server timestamp of the response
      type: object
      title: ResponseMeta
    ErrorDetail:
      properties:
        code:
          type: string
          title: Code
          description: Machine-readable error code
          examples:
            - not_found
        message:
          type: string
          title: Message
          description: Human-readable error message
          examples:
            - Resource not found
      type: object
      required:
        - code
        - message
      title: ErrorDetail
    AudienceContactFailureGroup:
      properties:
        reason:
          type: string
          title: Reason
          description: Reason code for the failure
          examples:
            - not_in_audience
        contact_ids:
          items:
            type: string
          type: array
          title: Contact Ids
          description: Contact IDs that failed for this reason
      type: object
      required:
        - reason
        - contact_ids
      title: AudienceContactFailureGroup

````