Hashids

Hashids is a small open-source library that generates short, unique, non-sequential ids from numbers. It converts numbers like 347 into strings like “yr8”, or array of numbers like [27, 986] into “3kTMd”. You can also decode those ids back. This is useful in bundling several parameters into one or simply using them as short UIDs. Hashids works similarly to the way integers are converted to hex, but with a few exceptions. The alphabet is not base16, but base base62 by default. The alphabet is also shuffled based on salt. We need ids to be nice and friendly especially if they end up being in the URL. Therefore, the algorithm tries to avoid generating most common English curse words by never placing the following letters (and their uppercase equivalents) next to each other. There are no collisions because the method is based on integer to hex conversion. As long as you don't change constructor arguments midway, the generated output will stay unique to your salt.