Serve security.txt as text/plain with utf-8 on Caddy

Why it matters

RFC 9116 requires the file to be sent as text/plain in utf-8. Tools may reject it if the server labels it as html, binary or another charset.

The fix

1. Serve the file with file_server from a real file named security.txt, which Caddy sends as text/plain with the utf-8 charset. If you use respond to serve the text instead, set the header explicitly.
2. Reload Caddy and check the Content-Type header again.

example.com {
	handle /.well-known/security.txt {
		header Content-Type "text/plain; charset=utf-8"
		root * /var/www/security
		file_server
	}
}

The examples use example.com. Replace it with your own domain.

Read the documentation ↗(opens in a new tab)

Related

• Reported by the security.txt check
• Publish a security.txt file
• Serve security.txt from /.well-known/
• Serve security.txt over https
• Add a Contact line to security.txt
• Fix the Contact value in security.txt
• Add an Expires line to security.txt
• Use an RFC 3339 date in the Expires line
• Renew the expired security.txt
• Renew security.txt before it expires
• Shorten the security.txt Expires date
• Fix repeated or insecure fields in security.txt
• Make the Canonical line match where the file is served