Change effective on 24 April 2018
To provide more visibility into the Node.js runtime, the Node.js Language Metrics feature surfaces additional Node.js-specific time series metrics within Application Metrics on the Heroku Dashboard. These additional metrics include Aggregate Time Spent in Garbage Collection, Aggregate Garbage Collections, Event Loop Latency, and Event Loop Usage.
If you are interested in participating in the private beta, send an email to firstname.lastname@example.org with the names of the applications on which you would like the feature to be enabled on.
For more information regarding Node.js Language Metrics, including setup instructions, please refer to the Devcenter Article.