ELI5: What is Google captcha and how it works?

Google CAPTCHA is a little safety test that checks if you’re a real person and not a robot trying to use a website automatically.

Think of it like a digital “Are you a human?” doorman at a store.

• If a website sees something that looks a bit suspicious, it may ask you to do a quick task, like click a box, choose pictures, or solve a small puzzle.
• Easy tasks for people can be hard for robots, so this helps websites stop spam, fake sign-ups, and other automated attacks.
• Google’s newer reCAPTCHA often works quietly in the background first, watching things like how you move your mouse, click, or type. If it is still unsure, it may show you a puzzle or checkbox.

So, CAPTCHA is a way websites protect themselves by asking, “Prove you’re human,” using simple tasks that people can do more easily than robots.