Json object not passed to GoogleApi.post call

[brandflownet]

I am trying to make POST call towards Search Console API. I got my example running under API Explorer, however when I try to make the same call from my meteor project, I am getting error:

Object {error: Object} error: Object code: 400 errors: Array[1] message: "Parse Error"
My code:

function fetchSEOForWebsite(website) {

    var call = 'webmasters/v3/sites/' + 'mdbootstrap.com' + '/searchAnalytics/query'
    var params = {
        "searchType": "web",
        "dimensions": [
            "query",
            "date",
            "page"
        ],
        "startDate": "2016-02-06",
        "endDate": "2016-02-08"
    }


    GoogleApi.post(call, {
        params: params
    }, function(error, answer) {

        console.log(answer);

    });
}

From Chrome console I can see POST payload:

searchType=web&dimensions=query%2Cdate%2Cpage&startDate=2016-02-06&endDate=2016-02-08

The same query works perfectly fine from API Explorer :

POST https://www.googleapis.com/webmasters/v3/sites/http%3A%2F%2Fmdbootstrap.com/searchAnalytics/query?key={YOUR_API_KEY}

{
 "searchType": "web",
 "dimensions": [
  "query",
  "date",
  "page"
 ],
 "startDate": "2016-02-06",
 "endDate": "2016-02-08"
}

I also checked paylod sent via API Explorer and it's different:

{ "searchType": "web", "dimensions": ["query","date","page"
], "startDate": "2016-02-06", "endDate": "2016-02-08" }

So it looks like for some reason my params are not passed as a JSON object to call...