What’s the difference between envelope-from and header-from domain reputation?

The envelope-from (also called the Return-Path or bounce address) is the domain used during the SMTP conversation. This is where bounce messages are sent and where SPF validation occurs.

The header-from is the domain in the visible From field that recipients see in their inbox. This is what DMARC aligns against and what users associate with your brand.

Both domains develop separate reputation tracks. Some ESPs use their own domains for envelope-from while letting you use your branded domain for header-from. This can complicate reputation because the signals split between two identities.

The envelope-from is like the shipping company's warehouse address stamped on the box. The header-from is the elegant letterhead inside that the recipient actually reads. Both affect whether your cargo reaches its destination.