reCAPTCHA keys overview

This document provides an overview of reCAPTCHA keys (also known as keys ).

A reCAPTCHA key is a unique, case-sensitive string of 40 characters that needs to be installed on web pages, in mobile applications, or at the WAF layer to integrate reCAPTCHA.

A reCAPTCHA key returns a score for each request, which is based on the user interactions with your site or application. By interpreting these scores, you can take appropriate actions for your site or application, such as allowing or blocking users.

Example reCAPTCHA key: 6Lcm3XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX5mfX

reCAPTCHA keys can have one of the following integration types:

  • SCORE : Returns risk scores. It doesn't display the I'm not a robotcheckbox and never shows CAPTCHA challenges.
  • CHECKBOX : Displays the I'm not a robotcheckbox and might show CAPTCHA challenges after the checkbox is checked.
  • POLICY_BASED_CHALLENGE ( preview ): Triggers CAPTCHA challenges based on a score threshold and challenge difficulty.
  • INVISIBLE : Doesn't display the I'm not a robotcheckbox, but might show CAPTCHA challenges after risk analysis.
The following table lists reCAPTCHA keys that are supported for each platform:
Platform
Description
Supported keys
Challenge type
web
For integration on web pages.
Score-based keys
SCORE
Checkbox keys
CHECKBOX
Policy-based challenge keys ( preview )
POLICY_BASED_CHALLENGE
mobile
For integration with Android and iOS apps.
reCAPTCHA keys for Android
SCORE
reCAPTCHA keys for iOS
SCORE
WAF
For web pages and APIs served through WAF or Edge compute servers.
action-token keys
SCORE and CHECKBOX
session-token keys
SCORE
challenge-page keys
INVISIBLE
API
For integration with APIs or clients like IoT devices that do not support the reCAPTCHA JavaScript or mobile SDKs.
express keys
SCORE

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