Get a Record Using an External ID

You can use the GET method of the sObject Rows by External ID resource to get records with a specific external ID.

The following example assumes there is a Merchandise__c custom object with a MerchandiseExtID__c external ID field.

Example usage for retrieving a Merchandise__c record using an external ID
curl https://MyDomainName.my.salesforce.com/services/data/v64.0/sobjects/Merchandise__c/MerchandiseExtID__c/123 -H "Authorization: Bearer token"
Example request body
none required
Example response body
{ 
    "attributes" : {
        "type" : "Merchandise__c",
        "url" : "/services/data/v64.0/sobjects/Merchandise__c/a00D0000008oWP8IAM"
     },
    "Id" : "a00D0000008oWP8IAM",
    "OwnerId" : "005D0000001KyEIIA0",
    "IsDeleted" : false,
    "Name" : "Example Merchandise",
    "CreatedDate" : "2012-07-12T17:49:01.000+0000",
    "CreatedById" : "005D0000001KyEIIA0",
    "LastModifiedDate" : "2012-07-12T17:49:01.000+0000",
    "LastModifiedById" : "005D0000001KyEIIA0",
    "SystemModstamp" : "2012-07-12T17:49:01.000+0000",
    "Description__c" : "Merch with external ID",
    "Price__c" : 10.0,
    "Total_Inventory__c" : 100.0,
    "Distributor__c" : null,
    "MerchandiseExtID__c" : 123.0
}