const axios = require('axios');
const httpEndpoint = 'https://octet-fullhistory.hexlant.com/v1/ETH';
const accessToken = '[[YOUR_ACCESS_TOKEN]]';
​
const instance = axios.create({
  baseURL: httpEndpoint,
  timeout: 1000,
  headers: {'Authorization': accessToken}
});

instance.post('/rpc', {
  jsonrpc: '2.0',
  method: 'eth_getBalance',
  params: ['0xa90742CDD09750829ee41E484C4dD89bEe425479'],
  id: 1
}).then((response) => {
  console.log(response.data);
}, (error) => {
  console.log(error);
});

{ 
    jsonrpc: '2.0', 
    result: '0x604e756c56f0000', 
    id: 1 
}