This section provides definitions for terms you’ll find throughout the Metawork docs.

An operation is an action in your software system, such as handling an HTTP request or a job from a queue.

A recording is the code execution of an instance of an operation. Recordings show the execution of all code that Metawork recorded.

A frame is the set of recorded data (context values, parameters, return values, etc) that represents a stack frame in your program. Frames can be generated by named or anonymous method calls or blocks, including blocks used for iterations. Recordings are made up of frames.


Context values

  • Context values are values implicitly defined and passed by runtimes as part of execution.
  • Context values are pink across the platform.
  • These values are distinct from function parameters in that they are not explicitly defined.
  • Context values include self values in Ruby, or this in Node.js.

Function arguments

  • Function arguments are values passed into functions.
  • Function arguments are green across the platform.
  • Each frame that has function parameters shows these in-line.

Return values

  • Return values are values returned as a result of a function’s execution.
  • Return values are blue across the platform.
  • Each frame that has a return value shows these in-line.


  • Exceptions are values that indicate a disruption of the normal flow of an operation.
  • Exceptions are red across the platform.

Call sites
Call sites show you where your code was called.

Sometimes during execution, intervening code that Metawork did not record calls your code. Call sites for this code are called “indirect” call sites, because Metawork doesn’t display where it was called.


Async function
Async functions are functions that execute asynchronously, outside the currently displayed thread of execution.



Flags are attached to recordings to indicate that they are of note and worth you noticing.

Metawork service
The Metawork service is a background process which processes recordings and makes Metawork accessible on a local port.