X-Hacker
The HTTP X-Hacker response header is an unofficial HTTP header used by WordPress.com and Automattic properties as an easter egg containing recruitment messages.
Note
The "X-" naming convention for HTTP headers, "X" referring to "experimental", has been deprecated and needs to be transitioned to the formal naming convention for HTTP headers.
Usage
Automattic, the company behind WordPress.com, WooCommerce, Tumblr, and other web properties, adds the X-Hacker header to HTTP responses as a recruiting tool aimed at developers inspecting network traffic. The header value contains a message inviting anyone reading the raw response headers to apply for a position at the company.
This practice reflects a tradition in web development where companies embed hidden messages in HTTP headers, HTML comments, or console output to reach technically curious people. The header carries no functional purpose for clients or intermediaries. Browsers and proxies ignore the value. The header appears on WordPress.com-hosted sites and other Automattic-run services, distinguishing these from self-hosted WordPress installations where the header is absent.
The header sits in the same category as other informational and branding headers like X-Powered-By, serving as a human-readable marker rather than a machine-readable directive. Sites powered by WordPress.com's infrastructure often send X-Hacker alongside X-Pingback and X-Redirect-By.
Values
The value is a freeform text string containing a recruitment message. Automattic uses several variations across different properties and time periods, all pointing to job application pages at Automattic or its subsidiary brands.
Example
The most common variation found on WordPress.com VIP properties and major media sites hosted on the platform. The message invites readers to apply and mention the header in their application.
X-Hacker: If you're reading this, you should visit https://join.a8c.com/viphacker and apply to join the fun, mention this header.
A shorter variation appears on other Automattic platform-hosted properties.
X-Hacker: Want root? Visit join.a8c.com/hacker and mention this header.
Another variation omits the specific path, directing to the main Automattic careers page.
X-Hacker: Want root? Visit join.a8c.com and mention this header.
A full response from a WordPress.com-hosted site showing X-Hacker alongside other common WordPress HTTP headers.
HTTP/1.1 200 OK
Content-Type: text/html; charset=UTF-8
X-Hacker: If you're reading this, you should visit https://join.a8c.com/viphacker and apply to join the fun, mention this header.
X-Pingback: https://example.re/xmlrpc.php
X-Powered-By: WordPress.com
Takeaway
The X-Hacker header is a recruitment easter egg embedded in HTTP responses by Automattic and WordPress.com, carrying job application messages aimed at developers who inspect response headers.