Request Body is going empty when sending a REST API request outbound

[maneesh3]

Hi Team,

I am working on a REST API integration with a third party application and while sending data from ServiceNow, I am unable to send the parameters in Request Body. Client is asking for to send data through Request Body: Following I have approached:

Below I have given in PUT method:

Although Request body is null.

Please suggest where I am doing wrong.

Thank you!

[Ankur Bawiskar]

@maneesh3 

you can grab the preview script from the REST Message itself

what debugging did you do?

💡 If my response helped, please mark it as correct ✅ and close the thread 🔒— this helps future readers find the solution faster! 🙏

[maneesh3]

Hi Ankur,

I have used preview script code in BR and debugging is just I have tested with static sample with 3rd party and static sample testing is working but not dynamic :

code used:

 try {

    var r = new sn_ws.RESTMessageV2('vCx360', 'Default PUT');

    // Basic fields

    r.setStringParameterNoEscape('comments', current.comments);

    r.setStringParameterNoEscape('number', current.number);

    r.setStringParameterNoEscape('description', current.description);

    r.setStringParameterNoEscape('short_description', current.short_description);

    r.setStringParameterNoEscape('state', current.state);

    r.setStringParameterNoEscape('correlation_id', current.correlation_id);

    // Attachment handling

    var attachmentGR = new GlideRecord('sys_attachment');

    attachmentGR.addQuery('table_sys_id', current.sys_id);

    attachmentGR.addQuery('table_name', current.getTableName());

    attachmentGR.orderByDesc('sys_created_on');

    attachmentGR.setLimit(1); // only latest attachment

    attachmentGR.query();

    if (attachmentGR.next()) {

        var fileName = attachmentGR.file_name + '';

        var fileType = attachmentGR.content_type + '';

        // Get file content in Base64

        var gsa = new GlideSysAttachment();

        var fileContent = gsa.getBytes(attachmentGR);

        var encodedContent = GlideStringUtil.base64Encode(fileContent);

        // Set parameters

        r.setStringParameterNoEscape('file_name', fileName);

        r.setStringParameterNoEscape('file_type', fileType);

        r.setStringParameterNoEscape('file_content', encodedContent);

    } else {

        // No attachment found

        r.setStringParameterNoEscape('file_name', '');

        r.setStringParameterNoEscape('file_type', '');

        r.setStringParameterNoEscape('file_content', '');

    }

    // Execute REST call

    var response = r.execute();

    var responseBody = response.getBody();

    gs.info("Response: " + responseBody);

} catch (ex) {

    gs.error("REST message failed: " + ex.message);

}

})(current, previous);

static sample:

{
  "correlation_id": "73",
  "short_description": "Network outage in Bangalore office",
  "description": "Users are unable to connect to VPN and internal applications since 9 AM IST. The issue appears to be network related.",
  "comments": "Initial investigation started. Network team has been notified and working on root cause analysis."
"number": "CSV0028225",

"state": "open",

  "attachments": [
    {
      "file_name": "network_logs.txt",
      "content_type": "text/plain",
      "content": "U2FtcGxlIGxvZ3MgY29udGFpbmluZyBuZXR3b3JrIGVycm9ycyBhbmQgY29ubmVjdGlvbiB0aW1lb3V0cw=="
    }
  ]
}

Static sample test shows 200 code but when running dynamic it is not even triggering

[maneesh3]

Hi Ankur,

Can you please look below my comment

[MaxMixali]

✅ Issue: REST API request body is null when sending PUT from ServiceNow

You’re sending a PUT but the request body is empty. This happens when parameters are sent as query params instead of the body, or Content-Type/body template is missing.

-----------------------------------------------------------
A) REST Message + Method (classic)
-----------------------------------------------------------
1. Create REST Message → your endpoint.
2. HTTP Method = PUT.
3. HTTP Headers:
- Content-Type: application/json
4. Request body template:
{
"id": "${id}",
"status": "${status}",
"notes": "${notes}"
}
5. Define variables (id, status, notes).

Script test:
```javascript
var m = new sn_ws.RESTMessageV2('THIRD_PARTY_MSG','put');
m.setStringParameter('id', '12345');
m.setStringParameter('status', 'OPEN');
m.setStringParameter('notes', 'Updated from ServiceNow');
m.setRequestHeader('Content-Type','application/json');
var payload = { id: '12345', status: 'OPEN', notes: 'Updated from ServiceNow' };
m.setRequestBody(JSON.stringify(payload));
var resp = m.execute();
gs.info('HTTP ' + resp.getStatusCode() + ' body=' + resp.getBody());
```

-----------------------------------------------------------
B) Flow Designer → REST Step
-----------------------------------------------------------
1. Add REST Action → Method: PUT.
2. Content type: application/json.
3. Use Request Body mapping, not Request Parameters.
Example JSON:
{
"id": "{{trigger.record.number}}",
"status": "OPEN",
"notes": "Updated by flow {{now}}"
}

-----------------------------------------------------------
C) Fully Scripted Example
-----------------------------------------------------------
```javascript
var r = new sn_ws.RESTMessageV2();
r.setEndpoint('https://api.thirdparty.com/v1/tickets/12345');
r.setHttpMethod('PUT');
r.setRequestHeader('Content-Type','application/json');
var body = { id: '12345', status: 'OPEN', notes: 'Updated from ServiceNow' };
r.setRequestBody(JSON.stringify(body));
var res = r.execute();
gs.info('Status=' + res.getStatusCode() + ' Body=' + res.getBody());
```

-----------------------------------------------------------
Troubleshooting Checklist
-----------------------------------------------------------
- Empty Request body field → must fill it or call setRequestBody().
- Only Parameters mapped → move to Request Body.
- Content-Type must be application/json.
- Verify parameter placeholders resolve properly.
- Outbound HTTP Logs → check sys_http_request/sys_http_response.
- Add gs.info('REQ BODY=' + r.getRequestBody()); to verify.

-----------------------------------------------------------
✅ Minimal Working PUT
-----------------------------------------------------------
```javascript
var m = new sn_ws.RESTMessageV2('MY_MSG','put');
m.setRequestHeader('Content-Type','application/json');
m.setRequestBody('{"ping":"pong"}');
var res = m.execute();
gs.info(res.getStatusCode() + ' ' + res.getBody());
```

If this works, your issue is parameter mapping or Content-Type.