URL will look something like this:
onlinejsonviewer.dev/{unique_key}
onlinejsonviewer.dev/{unique_key}.json
When you edit any stored JSON string, tool will save the edited JSON on seprate link.
So your URL will look something like this,
onlinejsonviewer.dev/{unique_key}/{version}
onlinejsonviewer.dev/{unique_key}/{version}.json
Here {version} denotes the version number of the stored JSON string,
just like the normal URL version URL which ends with .json will return the output with application/json content type.