How do sites like Opensea get all their data so fast? Because getting the data from the blockchain and fetching the tokenURi's takes a lot of time. So I thought they might store all the assets, events, users in a database, but wouldn't that be a huge amount of data?
How do sites like Opensea get all their data so fast?
They run their own client node. And you can too - see the Nodes and Clients section of the official site.