New charges for reCaptcha spur web security firm Cloudflare to develop its own identity-checking software

The days of clicking on traffic lights to prove you are not a robot could be ending after Google’s decision to charge for the tool prompted one of the web’s biggest infrastructure firms to ditch it for a competitor.

“Captcha” – an awkward acronym for “completely automated public Turing test to tell computers and humans apart” – is used by sites to fight automated abuses of their services. For years, Google’s version of the test, branded reCaptcha, has dominated, after it acquired the company that developed it in 2009 and offered the technology for free worldwide.