How do we figure out if APM agent in node.js is capturing & Sending data to ElasticSearch for Successful transactions?

As mentioned here Does APM support loopback? we don't have built-in support for Loopback yet. Your best bet at the moment is to try and use the Node.js Agent API to set it up: Get started with a custom Node.js stack | APM Node.js Agent Reference [4.x] | Elastic

best,
Ron Cohen