How to send JSON object as JSON String with Postman?

Question

I want to send a JSON request but problem is I need to send my userPropertiesAsJsonString field as JSON string.

How can I send userPropertiesAsJsonString as JSON string?

{
    "User" : {
        "userId" : "11111",
        "userPropertiesAsJsonString" : ?
    }
}

userPropertiesAsJsonString is;

{
    "properties" : {
        "propertyName" : "test",
        "propertyDesc" : "desc"
    }
}

Answer 1

Jason Mullings' answer did not work for me, but it was an excellent base that allowed me to come up with a solution to a problem very similar to yours.

In the Pre-request Script tab,

const userPropertiesAsJsonString = {
    "properties" : {
        "propertyName" : "test",
        "propertyDesc" : "desc"
    }
}

pm.environment.set(
    'userPropertiesAsJsonString',
    JSON.stringify(JSON.stringify(userPropertiesAsJsonString))
);

Then, in the Body tab,

{
    "User" : {
        "userId" : "11111",
        "userPropertiesAsJsonString" : {{userPropertiesAsJsonString}}
    }
}

Stringifying the userPropertiesAsJsonString variable twice will allow you to escape the JSON string (solution obtained from this answer; refer to this gist for a more detailed explanation) which will then allow you to obtain a request body that looks like the one in the answer provided by sanatsathyan.

Answer 2

Try this :

{
    "User" : {
        "userId" : "11111",
        "userPropertiesAsJsonString" : "{\"properties\" : {\"propertyName\" : \"test\",\"propertyDesc\" : \"desc\"}}"
    }
}