I can't understand what it is for
We provide Sandbox mode that allows you to see and solve your captchas by yourself.
please note that captchas sent in Sandbox mode are also charged
When Sandbox mode is enabled your captchas will not be distributed to wokers.
Normal captchas will be availble in Workers Cabinet
Token-based captchas like ReCaptcha V2, hCaptcha, GeeTest, etc are available in Workers' software
to use wokers' software you need to switch to "Worker" mode using the top right dropdown menu. Then copy workers' key and use it in the software.
ReCaptcha V3 is not supported
in SandBox and will be distributed to workers.