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I guess very much time because I've started working on it on my very first days on STEEM.

This tool was originally created by @omeratagun and I've done the redesign and refactoring.

So I guess, from the very first second until now, something between 50 and 60 hours.

It would take about 20 if I've started on it today, knowing all things I've learned so far.

But hey, that's the way of knowledge!