Option 1:


Sample Apex Class:


public class Utility {

    public static Boolean sandboxBool;
    
    public static Boolean isSandbox() {
        if ( sandboxBool == null ) 
        sandboxBool = URL.getSalesforceBaseUrl().getHost().left(2).equalsignorecase(‘cs’);
        return sandboxBool;
    }



}


Controller/Trigger calling:


system.debug(‘ o ‘ + Utility.isSandbox());


Option 2:


Sample SOQL:

SELECT Id, IsSandbox, Name FROM Organization LIMIT 1

If IsSandbox is true, then it is Sandbox else it is Production.