I think there may be a bit of a misunderstanding here. RunKit does not send you a container for you to interact with manually, in fact there is nothing in the RunKit UI to "mess around" with the container itself. RunKit is a coding notebook that is backed by containers (and automatic shrink-wrapping of dependencies) to guarantee determinism over multiple runs. In other words, it is a code snippet, but with a run button attached.

Nothing prevents you from 1) copy pasting the code to your own computer to run it exactly the same way as you would have previously done, or even better 2) hitting the "download" link on the left which downloads the code + shrink-wrap file so you are using the same dependencies as the user. On top of that, we have also made stack traces and other elements of the UI a lot friendlier.

From a reproducibility perspective, the notebook represents an undeniable instance that the bug did happen, along with all the background information you are usually asked (what version of node? what version of package? any other dependencies?). The goal is to make that all apparent in the code itself, vs extraneous other files like package.json or such. Here is an example: https://runkit.com/tolmasky/my-bug/1.0.0

If you are interested in the underlying technology, we've documented it here: http://blog.runkit.com/2015/09/10/time-traveling-in-node.js-...