From
The HTTP From request header contains an email address identifying the human operator responsible for the requesting user agent.
Usage
The From header provides a contact address for the person
controlling the client making the request. The primary use
case is automated agents such as web crawlers, bots, and
monitoring tools. Including a valid email address allows
server administrators to reach the operator when the
automated agent causes problems like excessive request
rates, accessing restricted paths, or ignoring
robots.txt rules.
Robot operators include the From header as a courtesy and accountability measure. Search engine crawlers, SEO auditing tools, and link validators commonly set this header to a webmaster contact address.
The From header is not intended for Authentication purposes. The value is not verified by the server and carries no access control significance. Sensitive deployments avoid sending this header because the email address travels in cleartext and is visible to every intermediary along the request path.
Values
The value is a single email address conforming to the
mailbox format. The recommended form is addr-spec
(bare address without display name or angle brackets),
though the mailbox production technically permits
both forms.
From: <email-address>
Example
A search engine crawler identifies its operator with a contact email address. Server administrators seeing unusual traffic patterns from this crawler send a message to the listed address.
From: crawler-admin@example.re
An SEO monitoring tool running automated site audits includes the contact address of the team operating the tool.
From: seo-team@agency.example.re
A combined request from an automated bot shows the From header alongside the User-Agent header, giving the server administrator both the software name and the operator contact.
User-Agent: ExampleBot/2.1
From: botmaster@example.re
Takeaway
The HTTP From header carries the email address of the human operator behind a requesting user agent, serving as a contact channel primarily for automated crawlers and bots.