Unless it's a big site that will get targeted specifically, custom solutions can be made without being such a hassle. Lichess have you move a chess piece. Forum

Unless it's a big site that will get targeted specifically, custom solutions can be made without being such a hassle. Lichess have you move a chess piece. Forums I've used have had a simple question ala "what is 4 + five". A newspaper has a question based on the article before you can comment to prove you read it. These are much better for the users, you share less data with Google and others, and are fairly trivial to implement. Easy to circumvent, but spammers aren't looking at you specifically.