Envelope vs Header
Embed This Widget
Add the script tag and a data attribute to embed this widget.
Embed via iframe for maximum compatibility.
<iframe src="https://statuscodefyi.com/iframe/glossary/envelope-vs-header/" width="420" height="400" frameborder="0" style="border:0;border-radius:10px;max-width:100%" loading="lazy"></iframe>Paste this URL in WordPress, Medium, or any oEmbed-compatible platform.
https://statuscodefyi.com/glossary/envelope-vs-header/Add a dynamic SVG badge to your README or docs.
[](https://statuscodefyi.com/glossary/envelope-vs-header/)Use the native HTML custom element.
The distinction between SMTP envelope addresses (MAIL FROM/RCPT TO) used for routing, and email headers (From/To) displayed to users — they can differ.