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

# Check whether a phone can receive messages



## OpenAPI

````yaml /openapi/sinjapp-business.v1.yaml get /contacts/lookup
openapi: 3.0.3
info:
  title: Sinjapp Business API
  version: 1.0.0
  description: |
    Sinjapp Business exposes a Tenant API for customer messaging operations.
  license:
    name: Proprietary
    url: https://sinjapp.com/legal/terms
servers:
  - url: '{tenantBaseUrl}/api/v1'
    description: Tenant API
    variables:
      tenantBaseUrl:
        default: https://your-tenant.sinjapp.org
        description: >-
          Full customer tenant URL, including https://. Use the exact tenant
          workspace domain shown in the dashboard.
security:
  - ApiKeyAuth: []
tags:
  - name: Auth
    description: Tenant identity and runtime context.
  - name: Subscription
    description: >-
      Tenant subscription status. Payment and plan changes happen inside the
      tenant dashboard.
  - name: API Keys
    description: Tenant API credentials and scopes.
  - name: Sender Numbers
    description: Sender number registration and activation state.
  - name: Messages
    description: Sending and reading message logs.
  - name: Contacts
    description: Contact reachability checks.
  - name: Usage
    description: Usage counters and limits.
paths:
  /contacts/lookup:
    get:
      tags:
        - Contacts
      summary: Check whether a phone can receive messages
      operationId: lookupContact
      parameters:
        - name: phone
          in: query
          required: true
          schema:
            type: string
          example: '{recipient_phone}'
        - name: sender_number_id
          in: query
          schema:
            type: integer
        - name: sender_phone
          in: query
          schema:
            type: string
      responses:
        '200':
          description: Lookup result from Sinjapp.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ContactLookup'
        '422':
          $ref: '#/components/responses/ValidationError'
      security:
        - ApiKeyAuth:
            - contacts.lookup
components:
  schemas:
    ContactLookup:
      type: object
      properties:
        exists:
          type: boolean
        can_receive:
          type: boolean
        reason_code:
          type: string
          example: ok
        recipient_id:
          type: integer
          nullable: true
        is_verified:
          type: boolean
        phone_verified_at:
          type: string
          format: date-time
          nullable: true
  responses:
    ValidationError:
      description: Validation failed.
      content:
        application/json:
          schema:
            type: object
            properties:
              message:
                type: string
              errors:
                type: object
                additionalProperties:
                  type: array
                  items:
                    type: string
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: X-Api-Key

````