CoWin gets captcha; end game for coders trying to cheat COVID vaccination portal Critics say captcha verification while booking vaccination slot only makes the process cumbersome. CoWin shows vaccination successful without giving jab After India expanded its vaccination drive to include people aged between 18-44 years, booking an appointment on CoWin, the COVID-19 vaccine scheduling platform, has been nothing short of a tedious task. But techies and coders found a workaround to book the slots by running scripts to automate the process. It was good alternative for end users, but only while it lasted. To put an end to this practice, CoWin app has now been updated to include Captcha verification.