A system creates and monitors virtual threads within a node.js application. Callbacks executing within an event loop for a node.js system are identified and may be traced. The callbacks are associated with a context, and resources associated with execution flow during each context may be identified. Callback registrations, callback calls, and callback completion messages may each be detected and recorded. Each registration, call, and completion message is associated with a virtual thread or other transaction identifier. The timing information for each virtual thread and other resource usage for each context may then be identified, stitched together for distributed transactions and reported to a user to provide more detail for node.js application processing.