Cannot access tokens to integrate webhook in developer sandbox account

You don't need an access token to post a Glip webhook message. However, if you don't know your Glip Webhook address and want to detect it programmatically, then you can login your app and call the glip/webhooks endpoint to get a list of webhooks addresses.

To post a message to a Glip Webhook, read this blog for details on how to set it up and use any http POST request to send.

Here is some snippet code to post a message in Node JS, provided that you have the webhook_url

function post_message_to_group(){

  webhook_url = "https://hooks-glip.devtest.ringcentral.com/webhook/v2/f4baa67a-xx"

  var https = require('https');

  var url = webhook_url.replace("https://", "")

  var urlArr = url.split("/")

  var host = urlArr[0]

  var path = url.replace(host, "")

  var body = {

    "icon": "http://tinyurl.com/pn46fgp",

    "activity": "Beer consumed",

    "title": "Let's stop working and go to WaterDog to have a bear.",

    "body": "This is the body of the post"

  }

  var post_options = {

      host: host,

      path: path,

      method: "POST",

      headers: {

        'Content-Type': 'application/json'

      }

  }

  var post_req = https.request(post_options, function(res) {

      var response = ""

      res.on('data', function (chunk) {

          response += chunk

      });

      res.on("end", function(){

        console.log(response)

      });

  });

  post_req.write(JSON.stringify(body));

  post_req.end();

}