Alternativeto is an old player in this game. They, definitely have a better database, but it's quicker to add software on Alternative and we have a complete set of tools.
We are covering website, software, toolkit, code, API, and library. You'll have this detail in the detail sheet. In addition, if you sign in, the comparator allows you to filter by type (for example "software").
Alternative is focusing on comparison tools to make your selection faster. The database is growing but it still new. Join us to make a difference!
Also, when I hear "software" I expect software for the computer, not websites that provide a service.
I recommend https://alternativeto.net/ -- very easy to recommend alternatives and add new ones.