Hi team Need your suggestions on following Terminologies Customer - our product customer client

Question

Hi team Need your suggestions on following Terminologies Customer - our product customer client

- our customer's customer (end client)

We are introducing a feature where customer can configure some redirect url (to his website or survey form) and client
will be redirected to it after session between them

One security concern is what if customer configures some malicious url(to a phising site etc) and client gets attacked

Is there any way to ensure that the provided url is safe always?

I mean even if we manually verify the url and approve , he could change the content next moment

Apart from warning clients before redirecting, is there any way to ensure safety?

Any suggestions are welcome

Thanks