> ## Documentation Index
> Fetch the complete documentation index at: https://onextel-09023014.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Check an audience

> Check a file or link for valid numbers and columns without saving it.



## OpenAPI

````yaml api-reference/truecaller/openapi.yaml POST /v1/lists/validate
openapi: 3.1.0
info:
  title: OneXtel Truecaller Business Messaging API
  version: 1.0.0
  description: >
    Send verified business messages to Truecaller users: single messages,
    templates with

    personalisation, images, files and buttons, and campaigns to contact lists.


    Every request carries a workspace API key in the `x-api-key` header. Create
    one in the

    Truecaller campaigns portal under **Developers → API keys**.


    Errors are JSON with a single `error` string (and `details` for validation
    errors):


    ```json

    { "error": "invalid phone number" }

    ```
servers:
  - url: https://truecaller.udchowdhury.me
    description: Production
security:
  - apiKey: []
tags:
  - name: Messages
    description: Send one message and read its status.
  - name: Templates
    description: Reusable messages with variables, media and buttons.
  - name: Media
    description: Upload files to attach to templates.
  - name: Contact lists
    description: Audiences for campaigns.
  - name: Campaigns
    description: Send a template to a whole contact list, now or later.
  - name: Senders
    description: The verified business profiles your workspace sends from.
paths:
  /v1/lists/validate:
    post:
      tags:
        - Contact lists
      summary: Check an audience
      description: >-
        Checks a file or link without saving it. Takes the same bodies as Add
        contacts and returns counts, invalid numbers, columns and a short
        preview.
      operationId: validateAudience
      requestBody:
        required: true
        content:
          text/csv:
            schema:
              type: string
          application/json:
            schema:
              type: object
              properties:
                source:
                  type: string
                  enum:
                    - sheet
                    - url
                url:
                  type: string
      responses:
        '200':
          description: The check.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UploadResult'
components:
  schemas:
    UploadResult:
      type: object
      properties:
        rows:
          type: integer
        added:
          type: integer
        updated:
          type: integer
        invalid:
          type: integer
        duplicates_in_file:
          type: integer
        invalid_samples:
          type: array
          items:
            type: object
            properties:
              row:
                type: integer
              value:
                type: string
        phone_column:
          type: string
          example: phone
        attribute_columns:
          type: array
          items:
            type: string
          example:
            - name
            - city
  securitySchemes:
    apiKey:
      type: apiKey
      in: header
      name: x-api-key
      description: >-
        Workspace API key from **Developers → API keys**. It starts with
        `tc_live_`.

````

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