Possible to detect if URL is behind paywall?

I am writing a tool (in PHP) that will find broken links. It's meant to not only include HTTP 404, 500, etc. stati, but also links behind a paywall, region a.o.

I have thoroughly searched Stackoverflow, Google, and more places, but could not find the answer anywhere:

Is there any way to detect things like a paywall, making the URL unavailable (1-time payment, requiring sign up/in, region restricted)? Maybe a HTTP header, or some other indication?

Thanks in advance!