Download Email via IMAP with MailKit

Program.cs

using MimeKit;
using MailKit;
using MailKit.Search;
using MailKit.Security;
using MailKit.Net.Imap;

namespace MailKitDownloadImap;

class Program
{
    static void Main(string[] args)
    {
        using (var client = new ImapClient (new ProtocolLogger ("imap.log")))
        {
            client.Connect ("imap.fastmail.com", 993, SecureSocketOptions.SslOnConnect);

            client.Authenticate (Environment.GetEnvironmentVariable("IMAP_USERNAME"), Environment.GetEnvironmentVariable("IMAP_PASSWORD"));

            client.Inbox.Open (FolderAccess.ReadOnly);

            var uids = client.Inbox.Search (SearchQuery.All);

            foreach (var uid in uids) {
                var message = client.Inbox.GetMessage (uid);

                // write the message to a file
                message.WriteTo (string.Format ("{0}.eml", uid));
            }

            client.Disconnect (true);
        }
    }
}