How to limit the access to a specific webpage only to holders of a certain token/NFT

Hi Ethereans!

I'm looking to a way to limit the access to a specific webpage only to holders of a certain token/NFT. I've seen there is a platform called MintGate that does something similar but I couldn't find their GitHub repo. Do you have any hint of how to implement it or can you point me to any other projects that do something similar?

Thanks