Learn About reCaptcha Technology
Before getting into the details, it's worth seeing a high-level overview of how reCAPTCHA works.
reCAPTCHA is a Web service, meaning that the CAPTCHA images are served directly from our servers to the end users. Below is the basic lifecycle of a reCAPTCHA challenge:
- The user loads the web page with the reCAPTCHA challenge JavaScript embedded.
- The user's browser requests a challenge (an image with distorted text) from reCAPTCHA. reCAPTCHA gives the user a challenge and a token that identifies the challenge.
- The user fills out the web page form, and submits the result to your application server, along with the challenge token.
- reCAPTCHA checks the user's answer, and gives you back a response.
- If true, generally you will allow the user access to some service or information. E.g. allow them to comment on a forum, register for a wiki, or get access to an email address. If false, you can allow the user to try again.
