Gmx.us supports IMAP / SMTP
You can connect your emails using email apps (like Bird Mail, Microsoft Outlook or K-9 Mail). Using email apps will make you more productive and your email will always be available, even offline.
Setup Your gmx.us Email Account with Your Email App Using IMAP
To access your gmx.us email account from a Mobile email app, you'll need the IMAP and SMTP settings below: