In the polkadot docs under NFT's they write this:
A general-purpose blockchain is not built to natively understand the concept of NFTs. It is only natively aware and optimized for its own native tokens, but implementations built on such a chain are essentially "hacks".
Take Singular.app for example. When I log in and view my space. I INSTANTLY have my purchased NFT's. I see backend API calls to what I'm assuming involves the use of GraphQL, a query is passed with the Asset's remark ID.
Are they making writes to the block-chain, listening to the KSM chain on their serverd backend? They then filters any system.remark 'hacks' on the Kusama network, write it to their back-end to update any changes made to these NFTs, and then use GraphQL queries to fetch them?
When a user logs in, they query their Wallet address to their backend, which can then cross reference all NFT's associated with that walletAddress? Then retrieve the ipfs routed image?