HTTP Headers Analysis for https://validator.w3.org

Detected Technologies from Headers

See all in URL Inspect 1

Cloudflare CDN

HTTP Security Headers

Status

Strict-Transport-Security

Present

max-age=15552015; preload

Content-Security-Policy

Missing

Not configured Analyze

Content-Security-Policy-Report-Only

Missing

Not configured Analyze

X-Frame-Options

Excellent

deny

X-Content-Type-Options

Good

nosniff

Referrer-Policy

Missing

Not configured

Permissions-Policy

Missing

Not configured

Recommendations

• Increase HSTS max-age to at least 1 year and add includeSubDomains
• Add Content-Security-Policy header to prevent XSS attacks
• Add Referrer-Policy header (recommended: strict-origin-when-cross-origin)
• Consider adding Permissions-Policy to control browser features

Performance Headers

Connection

Performance

close

Transfer-Encoding

Performance

chunked

Vary

Performance

Accept-Encoding

connection: close
transfer-encoding: chunked
vary: Accept-Encoding

Caching Headers

No caching headers found

Content Headers

Content-Type

Content

text/html; charset=utf-8

content-type: text/html; charset=utf-8

Server Headers

Server

cloudflare

server: cloudflare

CORS Headers

No CORS headers found

Cookies Headers

Set-Cookie

Cookies

set-cookie: __cf_bm=uYfj5nEnvMrYZYtkNMCw7tw0x50xhDWnuSFXYUBDFBQ-1775771881.19535-1.0.1.1-6ciAunSmrn0c9wsSMDWJUsd4zjY_IZiSY8Ar2Bk86EGq4itkBF2oY7o7W8VxLF0Xewam3fu9mZGlKxxBApvim8qEK6YDECwXcdMbJEkqbfXl.8KBmw7nSP3EDtD9phJ_; HttpOnly; Secure; Path=/; Domain=w3.org; Expires=Thu, 09 Apr 2026 22:28:01 GMT

Other Headers

Alt-Svc

Other

h3=":443"; ma=86400

Cf-Cache-Status

Other

BYPASS

Cf-Ray

Other

9e9cc55179107a4d-IAD

Date

Other

Thu, 09 Apr 2026 21:58:01 GMT

Public-Key-Pins

Other

pin-sha256="cN0QSpPIkuwpT6iP2YjEo1bEwGpH/yiUn6yhdy+HNto="; pin-sha256="WGJkyYjx1QMdMe0UqlyOKXtydPDVrk7sl2fV+nNm1r4="; pin-sha256="LrKdTxZLRTvyHM4/atX2nquX9BeHRZMCxg3cf4rhc2I="; max-age=864000

X-Request-Id

Other

9e9cc55179107a4d

alt-svc: h3=":443"; ma=86400
cf-cache-status: BYPASS
cf-ray: 9e9cc55179107a4d-IAD
date: Thu, 09 Apr 2026 21:58:01 GMT
public-key-pins: pin-sha256="cN0QSpPIkuwpT6iP2YjEo1bEwGpH/yiUn6yhdy+HNto="; pin-sha256="WGJkyYjx1QMdMe0UqlyOKXtydPDVrk7sl2fV+nNm1r4="; pin-sha256="LrKdTxZLRTvyHM4/atX2nquX9BeHRZMCxg3cf4rhc2I="; max-age=864000
x-request-id: 9e9cc55179107a4d

Recommendations

Enable compression (gzip/brotli) to improve performance

Add Cache-Control header to optimize caching