Secure Headers

Security Headers are HTTP response headers that, when set, can enhance the security of your web application by enabling browser security policies.

You can assess the security of your HTTP response headers at

Recommendations used by secure,py and more information regarding security headers can be found at the OWASP Secure Headers Project .


Contain information about server software
Default Value: NULL (obfuscate server information, not included by default)

Strict-Transport-Security (HSTS)

Ensure application communication is sent over HTTPS
Default Value: max-age=63072000; includeSubdomains

X-Frame-Options (XFO)

Disable framing from different origins (clickjacking defense)
Default Value: SAMEORIGIN


Enable browser cross-site scripting filters
Default Value: 0


Prevent MIME-sniffing
Default Value: nosniff

Content-Security-Policy (CSP)

Prevent cross-site injections
Default Value: script-src 'self'; object-src 'self' (not included by default)*


Enable full referrer if same origin, remove path for cross origin and disable referrer in unsupported browsers
Default Value: no-referrer, strict-origin-when-cross-origin


Prevent cacheable HTTPS response
Default Value: no-cache


Limit browser features and APIs to specific origins. Empty list means that a feature is disabled.
Default Value: accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), camera=(), clipboard-read=(), clipboard-write=(), cross-origin-isolated=(), display-capture=(), document-domain=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), fullscreen=(), gamepad=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), speaker=(), speaker-selection=(), sync-xhr=(), usb=(), web-share=(), xr-spatial-tracking=() (not included by default)
Additional information:
  • The Strict-Transport-Security (HSTS) header will tell the browser to only utilize secure HTTPS connections for the domain, and in the default configuration, including all subdomains. The HSTS header requires trusted certificates and users will unable to connect to the site if using self-signed or expired certificates. The browser will honor the HSTS header for the time directed in the max-age attribute (default = 2 years), and setting the max-age to 0 will disable an already set HSTS header. Use the hsts=False option to not include the HSTS header in Secure Headers.
  • The Content-Security-Policy (CSP) header can break functionality and can (and should) be carefully constructed, use the csp=secure.ContentSecurityPolicy() option to enable default values.


secure_headers = secure.Secure()

Default HTTP response headers:

Strict-Transport-Security: max-age=63072000; includeSubdomains
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 0
X-Content-Type-Options: nosniff
Referrer-Policy: no-referrer, strict-origin-when-cross-origin
Cache-control: no-cache, no-store, must-revalidate, max-age=0
Pragma: no-cache
Expires: 0


You can toggle the setting of headers with default and override default values by passing a class to the following options:

  • server - set the Server header, secure.Secure(server=secure.Server()) (default=False)
  • hsts - set the Strict-Transport-Security header secure.Secure(hsts=secure.StrictTransportSecurity()) (default=True)
  • xfo - set the X-Frame-Options header secure.Secure(xfo=secure.XFrameOptions()) (default=True)
  • xxp - set the X-XSS-Protection header secure.Secure(xxp=secure.XXSSProtection()) (default=True)
  • content - set the X-Content-Type-Options header secure.Secure(content=secure.XContentTypeOptions()) (default=True)
  • csp - set the Content-Security-Policy secure.Secure(csp=secure.ContentSecurityPolicy()) (default=False) *
  • referrer - set the Referrer-Policy header secure.Secure(referrer=secure.ReferrerPolicy()) (default=True)
  • cache - set the Cache-control header secure.Secure(cache=secure.CacheControl()) (default=True)
  • permissions - set the Permissions-Policy header secure.Secure(permissions=secure.PermissionsPolicy()) (default=False)


import secure

csp = secure.ContentSecurityPolicy()
xfo = secure.XFrameOptions().deny()

secure_headers = secure.Secure(csp=csp, hsts=None, xfo=xfo)

. . .


HTTP response headers:

x-frame-options: deny
x-xss-protection: 0
x-content-type-options: nosniff
content-security-policy: script-src 'self'; object-src 'self'
referrer-policy: no-referrer, strict-origin-when-cross-origin
cache-control: no-store