HTTP Headers Analysis for https://mdn.dev

Detected Technologies from Headers

See all in URL Inspect 9

Gravatar

YouTube

Alchemer

GitHub

Google Cloud Storage

Google Static File Front End

Stripe

Transcend

Varnish

HTTP Security Headers

Status

Strict-Transport-Security

Present

max-age=63072000

Content-Security-Policy

Basic

default-src; script-src; script-src-elem; +11 more Analyze

Content-Security-Policy-Report-Only

Missing

Not configured Analyze

X-Frame-Options

Excellent

DENY

X-Content-Type-Options

Good

nosniff

Referrer-Policy

Good

strict-origin-when-cross-origin

Permissions-Policy

Missing

Not configured

Recommendations

• Increase HSTS max-age to at least 1 year and add includeSubDomains
• Improve CSP by adding more specific directives and removing 'unsafe-inline'
• Consider adding Permissions-Policy to control browser features

Performance Headers

Accept-Ranges

Performance

bytes

Connection

Performance

close

Vary

Performance

Accept-Encoding

accept-ranges: bytes
connection: close
vary: Accept-Encoding

Caching Headers

Age

Caching

2653

Cache-Control

Caching

public, max-age=3600

Etag

Caching

"05cdc3b44c312c7b3935bc0c8e6c9a84"

Expires

Caching

Wed, 07 Oct 2026 02:43:47 GMT

Last-Modified

Caching

Wed, 07 Oct 2026 01:17:46 GMT

age: 2653
cache-control: public, max-age=3600
etag: "05cdc3b44c312c7b3935bc0c8e6c9a84"
expires: Wed, 07 Oct 2026 02:43:47 GMT
last-modified: Wed, 07 Oct 2026 01:17:46 GMT

Content Headers

Content-Length

Content

118852

Content-Type

Content

text/html

content-length: 118852
content-type: text/html

Server Headers

Server

Google Frontend

server: Google Frontend

CORS Headers

No CORS headers found

Cookies Headers

No cookies headers found

Other Headers

Date

Other

Wed, 07 Oct 2026 14:58:35 GMT

Via

Other

1.1 google, 1.1 varnish, 1.1 varnish, 1.1 varnish

X-Cache

Other

MISS, HIT, HIT

X-Cache-Hits

Other

0, 1678, 0

X-Cloud-Trace-Context

Other

bb9b0510fc80463dc87c0191f771d3b4

X-Goog-Generation

Other

1791335865937047

X-Goog-Hash

Other

crc32c=dZdjzA==, md5=Bc3DtEwxLHs5NbwMjmyahA==

X-Goog-Meta-Goog-Reserved-File-Mtime

Other

1791334762

X-Goog-Metageneration

Other

1

X-Goog-Storage-Class

Other

STANDARD

X-Goog-Stored-Content-Encoding

Other

identity

X-Goog-Stored-Content-Length

Other

118852

X-Guploader-Uploadid

Other

AP6rU83uonkbGVZQAF_2Pe7UOxNXxXLgNKeoow4n-T69bkuiRxndOKOVgChKZZPKC02vdx93

X-Served-By

Other

cache-bfi-krnt7300047-BFI, cache-bfi-krnt7300047-BFI, cache-bfi-krnt7300047-BFI, cache-ewr-kewr1740081-EWR

X-Timer

Other

S1791385116.800903,VS0,VE71

date: Wed, 07 Oct 2026 14:58:35 GMT
via: 1.1 google, 1.1 varnish, 1.1 varnish, 1.1 varnish
x-cache: MISS, HIT, HIT
x-cache-hits: 0, 1678, 0
x-cloud-trace-context: bb9b0510fc80463dc87c0191f771d3b4
x-goog-generation: 1791335865937047
x-goog-hash: crc32c=dZdjzA==, md5=Bc3DtEwxLHs5NbwMjmyahA==
x-goog-meta-goog-reserved-file-mtime: 1791334762
x-goog-metageneration: 1
x-goog-storage-class: STANDARD
x-goog-stored-content-encoding: identity
x-goog-stored-content-length: 118852
x-guploader-uploadid: AP6rU83uonkbGVZQAF_2Pe7UOxNXxXLgNKeoow4n-T69bkuiRxndOKOVgChKZZPKC02vdx93
x-served-by: cache-bfi-krnt7300047-BFI, cache-bfi-krnt7300047-BFI, cache-bfi-krnt7300047-BFI, cache-ewr-kewr1740081-EWR
x-timer: S1791385116.800903,VS0,VE71

Recommendations

Enable compression (gzip/brotli) to improve performance