Seems like a lot of these can be replaced by a line of python (or javascript or gnu util).
- backslash escapes: `print(text)`
- b64 decode: `base64.b64decode('text')`
- html escape: `html.escape('<h1>hello</h1>')`
...
And you have that in terminal for piping, output redirection and all of that unix goodness. GUI for this seems like a very peculiar option here, especially when it integrates with the rest of the environment only through clipboard.
Other than that big fan of the business model though you don't have a license specified in your github repo.