I strongly suggest to not use this. Instead, create URIs that contain arbitrary ...

I strongly suggest to not use this. Instead, create URIs that contain arbitrary content with the data URI scheme: https://en.wikipedia.org/wiki/Data_URI_scheme

The data URI scheme is standard and widely supported, does not rely on the host bitty.site being reachable and does not need JavaScript. One can even create data URIs with a small shell script that is given a filename argument:

  #!/bin/sh -eu
  printf 'data:%s;base64,%s' "$(file -bi "$1"|tr -d ' ')" "$(base64 -w 0 "$1")"