Whenever we want to read data from a blockchain, call a function, or make a transaction, we need to connect to the blockchain network. If we send a transaction, we need to send the signed transaction to one blockchain node so that it can send it out to all the other blockchain nodes in the network. You might have used an RPC URL from Alchemy, Infura, or Moralis Speedy Nodes in your blockchain applications before. These are all “node-as-a-service” providers, and give us an HTTP endpoint to send requests to a blockchain node. The same happens with cryptocurrency wallets, our Metamasks have a connection to a blockchain node built-in. In fact, if you go to your Metamask “networks” tab, you can see the exact RPC URL your Metamask is using!