telGuarder is one by clicking here, but also mobile phone app, which can tell you if the unknown number that called you is a nuisance call or not.
If you've been receiving nuisance calls and want to know who the caller is and what they're trying to say, then the most likely thing to do is just Google their number. There are websites such as White-pages that will reveal to you not only who he is but also his history.
telGuarder is one such website that talks except from Greek and many languages and provides corresponding information for each country you declare to it. In its Greek version it is particularly useful tool as it shows all recent phone number ratings along with user reviews.
In addition to having a free app for Android and iOS, it can simply work from a browser. Simply go to their website, enter in the relevant field the number you want and see what other users write about this number.
You will also see various statistics, such as how many searches this number has had, how many mentions, what date it was last search, and a graphical table with the percentages scamor security.
Also an equally worthwhile app is truecaller and you can find it for free on the Play Store.
How I would like a machine. Unfulfilled dream.