This is a good start, however there are some useful features that could be expanded.
- Expand URL Template variable to header values
- Extract (JSonPath or XPath) results from request to a variable
- Keep the response of the request in the history
- Display/Esport the full raw transaction (back and forth) for debugging /sharing purposes

I am not fluent in Javascript enough to implement such features myself.

Thanks for this nice tool.

Edit: I don't seem to be able to add a request to a collection, the button does nothing whatever state the collections are in. Maybe am I missing something ?