For the producers who like to sample songs, and need to know what key it is in, there are several options. A simple, new option has arisen, created by redditor /u/r-morris.
Called "What's That Key", it is a website that uses Spotify's data on tracks to tell you both the BPM and Key signature of a track entered into the search bar.
Tools like this are useful because they allow you to easily know what songs are compatible for sampling, and which ones need to have pitch/BPM alterations for them to fit into your song.
While these tools can never be 100% effective - especially in the case of songs which change key, they are an incredibly handy tool to use alongside your ears, saving time for more hands-on parts of production.
It is also super handy for DJs who use software that doesn't detect these song attributes, or for those wanting to double check their software is reading it correctly.
Other software which does both at once are hard to find, normally meaning you need two apps/websites to get both bits of information.
If you like this, check out Key Finder by Ibrahim Sha'ath which also writes the key signature into the track's metadata and allows the use of custom codes such as Camelot or your own system.