often there is a audio version of captcha when it is being used, as for a firefox specific alternative, it's dependent on the websites implementation, firefox just reads what the website provides, and can't really replace a third parties verification process with our own, unfortunately. There are some solvers that might be of assistance as extensions https://addons.mozilla.org/en-US/firefox/addon/buster-captcha-solver/?src=search https://addons.mozilla.org/en-US/firefox/addon/recaptcha-solver/?src=search I can't verify how useful these are, as I haven't personally used them