To interact with Darwinia nodes, you can use web3.js library.
Getting Started — web3.js 1.0.0 documentation
https://web3js.readthedocs.io/en/v1.8.2/getting-started.html
Connecting with MetaMask
typescriptimport Web3 from 'web3'; const web3 = new Web3(Web3.givenProvider); // web3.eth
Connecting through RPC
typescriptimport Web3 from 'web3'; // const web3 = new Web3("https://pangolin-rpc.darwinia.network"); // const web3 = new Web3("https://pangoro-rpc.darwinia.network"); // const web3 = new Web3("https://crab-rpc.darwinia.network"); const web3 = new Web3("https://rpc.darwinia.network"); // web3.eth