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

# Update localized content

> Partially updates message content.

Optional `content` uses exactly one of `mjml`, `html`, `text`, or `payload`; the API
infers the editor type from that key. Content can only be updated while the parent
campaign is in `draft`. Non-workflow messages reject duplicate locales with `409 Conflict`.




## OpenAPI

````yaml /api-reference/campaigns-v2/campaigns-v2.yaml patch /campaign-messages/{campaign_message_id}/content/{id}
openapi: 3.0.3
info:
  title: Vero Open API v2
  version: 2.0.0
  description: >
    OpenAPI description for the API key-authenticated `api/v2` campaign and

    broadcast endpoints.


    Authentication uses the `Authorization` header. Both of these forms are
    accepted:


    - `Authorization: sk_valid_123`

    - `Authorization: Bearer sk_valid_123`

    - `revision: 2026-03-01`


    Campaign read endpoints require the `campaign:read` permission, and campaign

    write endpoints require the `campaign:write` permission.


    Broadcast read endpoints require the `broadcast:read` permission. A
    broadcast

    is a one-off or recurring message sent to an audience.
servers:
  - url: https://api.getvero.com/api/v2
security:
  - ApiKeyAuth: []
tags:
  - name: Broadcasts
  - name: Broadcast Messages
  - name: Broadcast Message Contents
  - name: Journeys
  - name: Journey Messages
  - name: Journey Message Contents
  - name: Campaigns
  - name: Campaign Messages
  - name: Campaign Message Contents
paths:
  /campaign-messages/{campaign_message_id}/content/{id}:
    patch:
      tags:
        - Campaign Message Contents
      summary: Update localized content
      description: >
        Partially updates message content.


        Optional `content` uses exactly one of `mjml`, `html`, `text`, or
        `payload`; the API

        infers the editor type from that key. Content can only be updated while
        the parent

        campaign is in `draft`. Non-workflow messages reject duplicate locales
        with `409 Conflict`.
      operationId: updateCampaignContent
      parameters:
        - name: campaign_message_id
          in: path
          required: true
          description: Campaign message ID.
          schema:
            type: integer
        - name: id
          in: path
          required: true
          description: Campaign content record ID.
          schema:
            type: integer
        - name: revision
          in: header
          required: false
          description: >-
            Optional dated API revision for the request. Must use `YYYY-MM-DD`
            format.
          schema:
            type: string
            pattern: ^\d{4}-\d{2}-\d{2}$
            example: '2026-03-01'
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/UpdateCampaignContentRequest'
            examples:
              HTML:
                summary: HTML
                value:
                  subject: Updated
                  content:
                    html: <p>Updated</p>
              Push:
                summary: Push
                value:
                  content:
                    payload:
                      payloads:
                        ios:
                          aps:
                            dasherized-key: dashed
                            underscored_key: underscored
        required: true
      responses:
        '200':
          description: Campaign content updated.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CampaignContent'
        '401':
          description: Missing or invalid API key.
        '403':
          description: The API key lacks permission to access this project.
        '404':
          description: Resource not found in this project.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/NotFoundError'
        '409':
          description: Content for this locale already exists on the message.
        '422':
          description: >-
            Invalid request payload, the campaign is not in draft, or
            unsupported content format.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorList'
        '503':
          description: API key validation is temporarily unavailable.
      security:
        - ApiKeyAuth: []
components:
  schemas:
    UpdateCampaignContentRequest:
      type: object
      properties:
        name:
          type: string
          nullable: true
        subject:
          type: string
          nullable: true
        preheader_text:
          type: string
          nullable: true
        locale:
          type: string
          nullable: true
          description: >-
            Localized rows may update locale; the default content variant cannot
            be localized in place.
        content:
          $ref: '#/components/schemas/CampaignContentBody'
      additionalProperties: false
    CampaignContent:
      allOf:
        - $ref: '#/components/schemas/CampaignContentListItem'
        - type: object
          required:
            - content
          properties:
            content:
              $ref: '#/components/schemas/CampaignContentBody'
              description: >
                Full body: exactly one of `mjml`, `html`, `text`, or `payload`
                is set.
    NotFoundError:
      type: object
      required:
        - error
      properties:
        error:
          type: string
          enum:
            - not_found
    ErrorList:
      type: object
      required:
        - errors
      properties:
        errors:
          type: array
          items:
            type: object
            required:
              - message
            properties:
              message:
                type: string
    CampaignContentBody:
      type: object
      description: >
        Exactly one of `mjml`, `html`, `text`, or `payload` must be present in
        write requests.

        Email messages accept `mjml`, `html`, or `text`. SMS accepts `text`.
        Push accepts `payload`.
      properties:
        mjml:
          type: string
          nullable: true
        html:
          type: string
          nullable: true
        text:
          type: string
          nullable: true
        payload:
          type: object
          nullable: true
          additionalProperties: true
    CampaignContentListItem:
      type: object
      description: >-
        List response item; body copy is omitted — fetch a single record for
        `content`.
      required:
        - id
        - locale
        - name
        - is_default
        - created_at
        - updated_at
      properties:
        id:
          type: integer
        locale:
          type: string
          nullable: true
          description: '`null` for the default content variant.'
        name:
          type: string
          nullable: true
        is_default:
          type: boolean
        subject:
          type: string
          nullable: true
        preheader_text:
          type: string
          nullable: true
        created_at:
          type: string
          format: date-time
        updated_at:
          type: string
          format: date-time
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: Authorization
      description: Accepts either a raw API key or `Bearer <key>`.

````