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

# Check Contacts Existence

> This identifies whether a contact is already registered using a given query parameter such as `email` or `phone` or `contactId`.
**Note**: You must provide only one of the parameters in the request.

**Required permission**: `view-livechat-contact`.

### Changelog
| Version      | Description |
| ---------------- | ------------|
|7.2.0             | Added       |

## OpenAPI

````json GET /api/v1/omnichannel/contacts.checkExistence
{
  "openapi": "3.0.0",
  "info": {
    "version": "1.0.0",
    "title": "Omnichannel"
  },
  "servers": [
    {
      "url": "https://apiexplorer.support.rocket.chat"
    }
  ],
  "tags": [
    {
      "name": "Omnichannel Users"
    },
    {
      "name": "Omnichannel Agents"
    },
    {
      "name": "Omnichannel Monitors"
    },
    {
      "name": "Omnichannel Visitors"
    },
    {
      "name": "Omnichannel Contacts"
    },
    {
      "name": "Omnichannel Rooms"
    },
    {
      "name": "Omnichannel Departments"
    },
    {
      "name": "Omnichannel Custom Fields"
    },
    {
      "name": "Omnichannel Business Hours"
    },
    {
      "name": "Omnichannel Priorities"
    },
    {
      "name": "Omnichannel Tags"
    },
    {
      "name": "Omnichannel Units"
    },
    {
      "name": "SLA Policies"
    },
    {
      "name": "Canned Responses"
    },
    {
      "name": "Omnichannel Transcript"
    },
    {
      "name": "Omnichannel Statistics"
    },
    {
      "name": "Omnichannel Agent Stats"
    },
    {
      "name": "Omnichannel Dashboards"
    },
    {
      "name": "Reports"
    },
    {
      "name": "Omnichannel Inquiries"
    },
    {
      "name": "Omnichannel Webhooks"
    },
    {
      "name": "Livechat"
    },
    {
      "name": "Livechat Appearance"
    },
    {
      "name": "Livechat Triggers"
    },
    {
      "name": "Livechat Messages"
    },
    {
      "name": "Livechat Page Visited"
    }
  ],
  "paths": {
    "/api/v1/omnichannel/contacts.checkExistence": {
      "get": {
        "summary": "Check Contacts Existence",
        "tags": [
          "Omnichannel Contacts"
        ],
        "responses": {
          "200": {
            "description": "OK",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "exists": {
                      "type": "boolean"
                    },
                    "success": {
                      "type": "boolean"
                    }
                  }
                },
                "examples": {
                  "Contact found": {
                    "value": {
                      "exists": true,
                      "success": true
                    }
                  },
                  "contact not found": {
                    "value": {
                      "exists": false,
                      "success": true
                    }
                  }
                }
              }
            }
          },
          "400": {
            "description": "Bad Request",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "success": {
                      "type": "boolean"
                    },
                    "error": {
                      "type": "string"
                    },
                    "errorType": {
                      "type": "string"
                    }
                  }
                },
                "examples": {
                  "Error from missing query parameters": {
                    "value": {
                      "success": false,
                      "error": "must have required property 'contactId'\n must have required property 'email'\n must have required property 'phone'\n must match exactly one schema in oneOf [invalid-params]",
                      "errorType": "invalid-params"
                    }
                  }
                }
              }
            }
          }
        },
        "operationId": "get-api-v1-omnichannel-contacts.checkExistence",
        "parameters": [
          {
            "$ref": "#/components/parameters/AuthToken"
          },
          {
            "$ref": "#/components/parameters/UserId"
          },
          {
            "name": "contactId",
            "in": "query",
            "description": "The contact's unique ID.",
            "required": false,
            "schema": {
              "type": "string",
              "example": "673c76df47a6c9b89dd263d8"
            }
          },
          {
            "schema": {
              "type": "string",
              "example": "example@mail.com"
            },
            "in": "query",
            "name": "email",
            "description": "The omnichannel contact's email address."
          },
          {
            "schema": {
              "type": "string",
              "example": "01234567843"
            },
            "in": "query",
            "name": "phone",
            "description": "Phone number of the omnichannel contact."
          }
        ],
        "description": "This identifies whether a contact is already registered using a given query parameter such as `email` or `phone` or `contactId`.\n**Note**: You must provide only one of the parameters in the request.\n\n**Required permission**: `view-livechat-contact`.\n\n### Changelog\n| Version      | Description |\n| ---------------- | ------------|\n|7.2.0             | Added       |"
      }
    }
  },
  "components": {
    "parameters": {
      "AuthToken": {
        "name": "X-Auth-Token",
        "in": "header",
        "description": "The `authToken` of the authenticated user.",
        "required": true,
        "schema": {
          "type": "string"
        },
        "example": "RScctEHSmLGZGywfIhWyRpyofhKOiMoUIpimhvheU3f"
      },
      "UserId": {
        "name": "X-User-Id",
        "in": "header",
        "description": "The `userId` of the authenticated user.",
        "required": true,
        "schema": {
          "type": "string"
        },
        "example": "rbAXPnMktTFbNpwtJ"
      }
    }
  }
}
````