I’m trying to build a C# application that needs to fetch emails from Gmail using IMAP over SSL connection. I’ve been searching for working examples but most of what I find online is outdated or doesn’t work properly with Gmail’s security requirements.
Has anyone successfully implemented this? I need to authenticate with Gmail and retrieve new messages programmatically. I’m specifically looking for code examples that use .NET framework libraries to establish the IMAP SSL connection to Gmail servers.
Any guidance on which libraries work best or sample implementations would be really helpful. I’m particularly interested in how to handle Gmail’s authentication properly.
Gmail IMAP is a pain because of OAuth2 requirements. I fought this same problem last year - MailKit library is the way to go. The built-in .NET IMAP stuff just doesn’t handle Gmail’s auth properly. Here’s what worked: set up OAuth2 credentials in Google Cloud Console, then use MailKit’s ImapClient with SSL on port 993. You can’t just use username/password anymore - you need to get an access token through Google’s OAuth2 flow. I wasted days trying to make native .NET libraries work, then switched to MailKit and had it running in hours. You could try app passwords to skip OAuth2 hassle, but Google’s killing that option anyway.
Honestly, just use app passwords if u dont want the OAuth headache. Go to Google account settings > securty > app passwords and generate one for your app. Then it’s just regular username/password auth with the app password instead of ur real one. Way simpler than dealing with OAuth tokens and refresh logic.
Just dealt with this on a client project. Tried a bunch of different ways but ImapX library ended up working best for Gmail’s quirks. You’ve gotta enable “Less secure app access” in Gmail settings, or use App Passwords if you’ve got 2FA turned on. Connect to imap.gmail.com, port 993, SSL on. The auth stuff was a pain - had to get the SSL protocols right and handle certificate validation properly. ImapX saves you from wrestling with .NET’s native classes. Watch out for Gmail’s connection limits though. Make sure you’re disposing connections properly and don’t leave them hanging open.