Optimism

1curl https://optimism.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H 'Content-Type: application/json' \
4  -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'

1await window.ethereum.request({
2  method: 'wallet_addEthereumChain',
3  params: [{
4    chainId: '0xa',
5    chainName: 'Optimism',
6    rpcUrls: ['https://optimism.therpc.io/<YOUR_KEY>'],
7    nativeCurrency: {
8      name: 'Ether',
9      symbol: 'ETH',
10      decimals: 18,
11    },
12    blockExplorerUrls: ['https://optimistic.etherscan.io'],
13  }],
14});