---
title: "Add Contacts to Audience"
method: POST
path: "/v1/audiences/{audience_id}/contacts"
tags: ["Audiences"]
---

# Add Contacts to Audience

`POST /v1/audiences/{audience_id}/contacts`

## Request

- Base URL: `https://api.monaco.com`
- URL: `https://api.monaco.com/v1/audiences/{audience_id}/contacts`
- Auth: none declared

Adds one or more contacts to an audience by their IDs.

Audiences are reusable and may be attached to multiple campaigns, so adding a contact here enrolls them in every campaign that uses this audience.

## Path parameters

- `audience_id` string, uuid, required

## Request body

- AudienceContactsRequest
  - `contact_ids` string[], required: IDs of the contacts to add or remove

## Response `200`

Successful Response

- PublicItemResponseAddAudienceContactsResponse
  - `data` AddAudienceContactsResponse, required
    - `audience_id` string, required: ID of the audience that was modified
    - `failures` AudienceContactFailureGroup[]: Contacts that exist but could not be added or removed, grouped by reason
      - `reason` string, required: Reason code for the failure
      - `contact_ids` string[], required: Contact IDs that failed for this reason
    - `added_count` integer, required: Number of contacts this call added to the audience
    - `unknown_contact_ids` string[]: Contact IDs that do not exist in the organization and were skipped
  - `meta` ResponseMeta
    - `timestamp` string, date-time: Server timestamp of the response

## Other responses

- `4XX`: Client error

## Changes

- **2026-11-03** `fc720ada2a81`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/monaco/apis/monaco-public-api/changes/v1/audiences/:audience_id/contacts/post.md)

---

[API](https://skmtc.dev/monaco/apis/monaco-public-api.md) - [All operations](https://skmtc.dev/monaco/apis/monaco-public-api/llms.txt) - [OpenAPI document](https://skmtc.dev/monaco/apis/monaco-public-api/revisions/fc720ada2a81?raw)