validate a text when we enter in TextField in mashup

Instead of using validators, you could have the service where you create the thing return a status message with either success or failure message.

Hi @Pratik_Aswale 

You cannot use the validator function to check whether Thing exists.

As @Rocko said you can use the service to validate it. Something like this

let result = "Thing already exist";
if(!Things[thingName])
{
 //Put your Script to create Thing
 
 result = "Thing created successfully";
}

/VR