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"
    }
}

What's the problem with pasting what you posted here in Postman? Should work if I'm not mistaken. Just make sure the quotes are escaped with `\"` instead of just `"` — Kevin, Jan 18 '18 at 08:55
If this is in JavaScript, can’t you just do `JSON.stringify(userPropertiesAsJsonString)` there? — Sebastian Simon, Jan 18 '18 at 08:55

score 32 · Accepted Answer · answered Jan 18 '18 at 08:56

32

Try this :

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

answered Jan 18 '18 at 08:56

sanatsathyan

1,713
12
18

3

This has to be in one line, and it is quite a crappy solution. I wish we could use `''` or (back ticks) – Paul Kruger Apr 17 '19 at 07:16

score 23 · Answer 2 · answered Jul 30 '20 at 19:39

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.

Using JSON.stringify twice is brilliant, it is the only solution that worked for me in Postman, thank you. — Brett, Jul 20 '21 at 00:25

score 8 · Answer 3 · answered Aug 27 '19 at 01:07

8

pre-request script:

let query = {}

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

body:

{{query}}

answered Aug 27 '19 at 01:07

Jason Mullings

850
14
10

Nested JSON needs to be escaped, so doesn't work – cmart Oct 05 '21 at 14:09

dwettstein · Answer 4 · 2018-01-18T09:26:43.710

As JSON means JavaScript Object Notation, so you can just copy the userPropertiesAsJsonString into the original JSON:

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

Copy and paste this JSON into the Postman request body (raw formatted) and set the header "Content-Type: application/json".

If you have to do more fancy stuff before the request you can execute a pre-request script in Postman: https://www.getpostman.com/docs/postman/scripts/pre_request_scripts

For more about JSON see here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON

This is what i would go for, just use the original JSON and not a string - As it's using Postman to `POST` the request payload, `JSON.stringify()` won't work as the app will fail the validation as it checking that the schema is valid JSON. — Danny Dainton, Jan 18 '18 at 09:20

score 1 · Answer 5 · answered Apr 06 '22 at 22:01

1

How to send JSON object as JSON String with Postman?

5 Answers5