gmx-webde-infrastructure

Bounce codes and SMTP errors explained

GMX WEB.DE Rate Limits Per Connection for New IPs in 2026

Understand GMX and WEB.DE's connection rate limits for new IPs. Prevent deliverability issues with real-time verification and inbox placement testing.

Email authentication: SPF, DKIM, DMARC, BIMI and MTA-STS

GMX and WEB.DE PTR and HELO Requirements for Direct Senders

Ensure your direct sends to GMX and WEB.DE succeed. Learn their PTR and HELO requirements, avoid bounces, and verify deliverability with MailTester’s.