Glossary

Review the definitions for terms used across Cloudflare’s Turnstile documentation.

Term	Definition
CAPTCHA	A CAPTCHA test is designed to determine if an online user is really a human and not a bot. CAPTCHA is an acronym that stands for "Completely Automated Public Turing test to tell Computers and Humans Apart."
secret key	The secret key allows communication between your application backend and the Cloudflare Turnstile server to validate the widget response.
sitekey	The sitekey is used to invoke Turnstile on your site.