This site was created by Patrick Kaeding in 2014. I created an older site, almost a decade earlier, that solved this same basic problem, albeit with less polish and more rough edges all around.
If you find this service useful, please consider making a donation. I work on this in my spare time, and don't make any money from it other than the advertisements. The revenue from that is very small, and only covers a portion of my hosting fees. Thank you!