Google offers reCAPTCHA (v3 and v2) and reCAPTCHA Enterprise to help you protect your sites from fraudulent activities, spam, and abuse. To know more about the features of reCAPTCHA and reCAPTCHA Enterprise, see Comparison of features between reCAPTCHA versions.
This document provides an overview of Google reCAPTCHA v3 and v2. For information about reCAPTCHA Enterprise, see the reCAPTCHA Enterprise documentation.
This documentation is designed for people familiar with HTML forms, server-side processing or mobile application development. To install reCAPTCHA, you might need to edit some code.
We hope you find this documentation easy to follow. You can ask a question about reCAPTCHA on
Stack Overflow, using the tag
To start using reCAPTCHA, you need to sign up for an API key pair for your site. The key pair consists of a site key and secret key. The site key is used to invoke reCAPTCHA service on your site or mobile application. The secret key authorizes communication between your application backend and the reCAPTCHA server to verify the user's response. The secret key needs to be kept safe for security purposes.
Now, perform the following steps to add reCAPTCHA to your site or mobile application:
- Choose the client-side integration:
- Verify the user's response.
Comparison of features between reCAPTCHA v3 and reCAPTCHA v2
The following table shows a comparison of the features in reCAPTCHA v3 and reCAPTCHA v2.
|Feature||reCAPTCHA v3||reCAPTCHA v2|
For more information, see Pricing.
|Free up to 1 million assessments per month*||Free up to 1 million assessments per month*|
|"I'm not a robot" widget support||No||Yes|
|Score granularity (security-review required)||4 levels||None|