Package free for use.
This package use ViaCep at https://viacep.com.br/ and all data are provided by it's services. So I'm not reponsable if they will decide to change links or stop service by they own decision.
ViaCep is a colaboraive platform and if you have something to help them to imprive jut doit.
Example o use:
using Vitsoftol.ViaCep.NetCore;
using Vitsoftol.ViaCep.NetCore.Models;
//Search by Zip Code
var address = SearchAddress.PorCep("15.802.328");
//Search by Address
var address = SearchAddress.PorEndereco(Estado.SP, "Catanduva","appendino");