The UUID standard has several versions. Version 4 for example is based on a completely random input. But it still encodes the version information and only uses 125bits of the possible 128 bits.
But for transferring these via HTTP, it is more efficient to encode them in BASE64. There are libraries for this (https://github.com/skorokithakis/shortuuid).
But what I am wondering: Is there an alternative standard for shorter ID-strings? Of course I could slap together a version-byte + n random bytes and encode them BASE64, having my own working 'short, random ID scheme', but I wonder if there is any alternative that someone already specified before I make my own.