It wasn’t difficult to solve, and it seemed to work when I used it on my own websites." Munsell goes on to state, after encountering a series of unintelligible images that despite refreshing "Again, and again, and again.
The captchas were not only difficult for a computer to read, but impossible for a human." Munsell then provided numerous examples.
Distributed Proofreaders was the first project to volunteer its time to decipher scanned text that could not be read by OCR.
This is done through a Java Script API with the server making a callback to re CAPTCHA after the request has been submitted.
The re CAPTCHA project provides libraries for various programming languages and applications to make this process easier.
In 2017, Google improved this mechanism, calling it an "invisible re CAPTCHA".
According to former Google "click fraud czar" Shuman Ghosemajumder, this capability "creates a new sort of challenge that very advanced bots can still get around, but introduces a lot less friction to the legitimate human." The re CAPTCHA tests are displayed from the central site of the re CAPTCHA project, which supplies the words to be deciphered.