A note sharing service where all the data is stored in the URL.
The entered text is read as an array of Unicode codepoints. The maximum numerical value of a codepoint is 0x10FFFF. Then we turn the array into a decimal number by interpreting each codepoint as a single digit of a large, base-10FFFF number. This decimal number is then converted to a base-83 number, which uses the 83 URL-safe characters to represent the number. This encoding algorithm is slow for longer messages, but it is also the most efficient.
This is just a proof-of-concept. Please do not store any important data using this service. I might change the encoding algorithm later and then all old URLs stop working and your data is quite difficult to recover.