As Fuse Network is EVM compatible it also supports the JSON-RPC API. JSON-RPC API is a standard way to communicate with blockchain nodes on EVM compatible chains. It is extensively used by Fuse API's under the hood, MetaMask, and various dApps (Decentralized Applications) on the network. Fuse Network EVM compatibility is a great strength that makes Fuse Network part of the global Ethereum ecosystem.
The goal of Fuse API is to provide more convenient interface with a lean learning curve, keeping the blockchain technology hidden an as engine under the hood. Though:
Sometimes we didn't invented yet or customized properly what you need
You want to port an existing dApp from other blockchain, or you already experienced in crypto and want to build a product on Fuse without the reliance on Fuse API's.