I want to have my website check to see if a user has any erc-20 or NFT 721 tokens when they visit my site. They will be using metamask (or something better?) And I would like to be able to assign specific data to be displayed depending on what tokens are present in their wallet.
Any help will be greatly appreciated! 
please ask if you need me to clarify or explain my question more accurately
Hi @Sensatori thanks for reaching out, I’m pinged our friends at MetaMask to get some information to point you in the right direction. A good place to start is here, https://metamask.github.io/metamask-docs/Main_Concepts/Getting_Started and here, https://metamask.github.io/metamask-docs/API_Reference/Ethereum_Provider.
Will write back once I get info from the MetaMask team.
Heard back from the MetaMask team, here’s their response,
MetaMask does not currently provide a method to query the user’s tokens, although there is an EIP for this feature. https://ethereum-magicians.org/t/eip-2256-add-wallet-getownedassets-json-rpc-method/3600/5