curl --request PUT \
  --url https://api.sandbox.paypathiq.com/v1/clients/{clientCode}/customers/{externalCustomerId} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": {
    "firstName": "Avery",
    "lastName": "Example"
  },
  "type": "person"
}
'

{
  "contacts": [
    {
      "address": {
        "countryCode": "IE",
        "line1": "1 Example Street",
        "line2": "Example Building",
        "locality": "Dublin",
        "postalCode": "D02 X285",
        "region": "Dublin",
        "type": "home"
      },
      "email": {
        "address": "avery@example.test",
        "type": "personal"
      },
      "externalContactId": "CON_7F3K2Q",
      "fullName": "Avery Example",
      "isCustomerSelf": true,
      "isMain": true,
      "phone": {
        "number": "+35315550123",
        "type": "mobile"
      }
    }
  ],
  "name": {
    "firstName": "Avery",
    "lastName": "Example"
  },
  "sourceReference": "member-ref-example",
  "type": "person",
  "externalCustomerId": "CUS_123",
  "updatedAt": "2026-08-29T12:00:00Z"
}

{
  "contacts": [
    {
      "address": {
        "countryCode": "IE",
        "line1": "1 Example Street",
        "line2": "Example Building",
        "locality": "Dublin",
        "postalCode": "D02 X285",
        "region": "Dublin",
        "type": "home"
      },
      "email": {
        "address": "avery@example.test",
        "type": "personal"
      },
      "externalContactId": "CON_7F3K2Q",
      "fullName": "Avery Example",
      "isCustomerSelf": true,
      "isMain": true,
      "phone": {
        "number": "+35315550123",
        "type": "mobile"
      }
    }
  ],
  "name": {
    "firstName": "Avery",
    "lastName": "Example"
  },
  "sourceReference": "member-ref-example",
  "type": "person",
  "externalCustomerId": "CUS_123",
  "updatedAt": "2026-08-29T12:00:00Z"
}

{
  "detail": "Request body is not valid JSON.",
  "requestId": "29400000-0000-4000-8000-000000000001",
  "status": 400,
  "title": "Request body is not valid JSON.",
  "type": "https://docs.paypathiq.com/problems/malformed_json"
}

{
  "detail": "API key is invalid, inactive, revoked, or for another environment.",
  "requestId": "29400000-0000-4000-8000-000000000001",
  "status": 401,
  "title": "API key is invalid, inactive, revoked, or for another environment.",
  "type": "https://docs.paypathiq.com/problems/invalid_api_key"
}

{
  "detail": "The Client code is unknown, the grant lacks the required scope, or the calling address is outside the grant's IP allowlist.",
  "requestId": "29400000-0000-4000-8000-000000000001",
  "status": 403,
  "title": "The Client code is unknown, the grant lacks the required scope, or the calling address is outside the grant's IP allowlist.",
  "type": "https://docs.paypathiq.com/problems/client_scope_denied"
}

{
  "detail": "Contacts can change only when every existing and submitted Contact has an externalContactId.",
  "requestId": "29400000-0000-4000-8000-000000000001",
  "status": 409,
  "title": "Contacts can change only when every existing and submitted Contact has an externalContactId.",
  "type": "https://docs.paypathiq.com/problems/contact_update_unsupported"
}

{
  "detail": "Request body exceeds the 256 KiB resource limit.",
  "requestId": "29400000-0000-4000-8000-000000000001",
  "status": 413,
  "title": "Request body exceeds the 256 KiB resource limit.",
  "type": "https://docs.paypathiq.com/problems/request_too_large"
}

{
  "detail": "Media type or content encoding is unsupported. Send uncompressed application/json for PUT and POST, and application/merge-patch+json for PATCH.",
  "requestId": "29400000-0000-4000-8000-000000000001",
  "status": 415,
  "title": "Media type or content encoding is unsupported. Send uncompressed application/json for PUT and POST, and application/merge-patch+json for PATCH.",
  "type": "https://docs.paypathiq.com/problems/unsupported_media_type"
}

{
  "detail": "Route parameters or the representation are invalid. Route parameters are checked before authentication. Field errors carry a code such as invalid_format, unrecognized_keys, custom, sensitive_external_id, or sensitive_source_reference.",
  "errors": [
    {
      "code": "invalid_format",
      "detail": "Invalid ISO date",
      "pointer": "/dueDate"
    }
  ],
  "requestId": "29400000-0000-4000-8000-000000000001",
  "status": 422,
  "title": "Route parameters or the representation are invalid. Route parameters are checked before authentication. Field errors carry a code such as invalid_format, unrecognized_keys, custom, sensitive_external_id, or sensitive_source_reference.",
  "type": "https://docs.paypathiq.com/problems/validation_error"
}

{
  "detail": "Each API key may send 60 requests per minute and run 1 request at a time. In sandbox, the same limits also apply per Client across all of its keys. Every request, including GET, counts.",
  "requestId": "29400000-0000-4000-8000-000000000001",
  "status": 429,
  "title": "Each API key may send 60 requests per minute and run 1 request at a time. In sandbox, the same limits also apply per Client across all of its keys. Every request, including GET, counts.",
  "type": "https://docs.paypathiq.com/problems/rate_limit_exceeded"
}

{
  "detail": "An unexpected error prevented a safe commit, and nothing was saved. Retry with backoff.",
  "requestId": "29400000-0000-4000-8000-000000000001",
  "status": 503,
  "title": "An unexpected error prevented a safe commit, and nothing was saved. Retry with backoff.",
  "type": "https://docs.paypathiq.com/problems/projection_unavailable"
}