Technical Information
| HTTP Status Code | 200 |
| HTTP Version | HTTP/1.1 |
| HTTPS | ✔ Available |
| IP Address | 151.101.121.91 |
| Server Software | Google Frontend |
| CDN | CDN (MISS, HIT) |
| Compression | gzip |
HTTP Status Code 200
HTTP Version HTTP/1.1
HTTPS ✔ Available
IP Address 151.101.121.91
Server Software Google Frontend
CDN CDN (MISS, HIT)
Compression gzip
Redirect Chain
| # | URL | HTTP Status Code | Status |
| 1 | https://developer.mozilla.org:443 | 302 | HTTP/2 302 |
| 2 | https://developer.mozilla.org/en-US/ | 200 | HTTP/2 200 |
#1 URL https://developer.mozilla.org:443
HTTP Status Code 302
Status HTTP/2 302
#2 URL https://developer.mozilla.org/en-US/
HTTP Status Code 200
Status HTTP/2 200
Performance
| DNS Lookup | 0.8 ms |
| TCP Connect | 2.3 ms |
| TLS Handshake | 9.2 ms |
| Time To First Byte (TTFB) | 14.1 ms |
| Content Download | 0.7 ms |
| Total Response Time | 14.8 ms |
DNS Lookup 0.8 ms
TCP Connect 2.3 ms
TLS Handshake 9.2 ms
Time To First Byte (TTFB) 14.1 ms
Content Download 0.7 ms
Total Response Time 14.8 ms
Security
| HTTPS | ✔ Enabled |
| HSTS | ✔ max-age=63072000 |
| CSP | ✔ Configured |
| X-Frame-Options | ✔ DENY |
| X-Content-Type-Options | ✔ nosniff |
| Referrer Policy | strict-origin-when-cross-origin |
| HTTP/2 | ⚠ HTTP/1.1 |
HTTPS ✔ Enabled
HSTS ✔ max-age=63072000
CSP ✔ Configured
X-Frame-Options ✔ DENY
X-Content-Type-Options ✔ nosniff
Referrer Policy strict-origin-when-cross-origin
HTTP/2 ⚠ HTTP/1.1
SEO Quick Check
| Title | MDN Web Docs |
| Meta Description | The MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps. |
| Canonical | https://developer.mozilla.org/en-US/ |
| Open Graph Title | MDN Web Docs |
| Open Graph Description | The MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps. |
| Open Graph Image | https://developer.mozilla.org/mdn-social-image.46ac2375.png |
| Twitter Card | summary |
Title MDN Web Docs Meta Description The MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps. Canonical https://developer.mozilla.org/en-US/ Open Graph Title MDN Web Docs Open Graph Description The MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps. Open Graph Image https://developer.mozilla.org/mdn-social-image.46ac2375.png Twitter Card summary Detected Technologies
| Technology | Google Analytics Node.js Stripe |
Technology Google Analytics Node.js Stripe
HTTP Headers
| Etag
| "34b29c866c02c08f4298d4ab4cc2e18b" |
| Content-type
| text/html |
| Server
| Google Frontend |
| X-goog-stored-content-encoding
| identity |
| Referrer-policy
| strict-origin-when-cross-origin |
| X-goog-metageneration
| 1 |
| X-goog-storage-class
| STANDARD |
| X-cloud-trace-context
| 846ec1d84ae27abdb4200a491a46be66 |
| X-goog-hash
| crc32c=Aa8Tlw==, md5=NLKchmwCwI9CmNSrTMLhiw== |
| Content-security-policy
| default-src 'self'; script-src 'report-sample' 'self' 'wasm-unsafe-eval' assets.codepen.io production-assets.codepen.io https://js.stripe.com transcend-cdn.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; script-src-elem 'report-sample' 'self' 'wasm-unsafe-eval' assets.codepen.io production-assets.codepen.io https://js.stripe.com transcend-cdn.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; style-src 'report-sample' 'self' 'unsafe-inline' transcend-cdn.com; object-src 'none'; base-uri 'self'; connect-src 'self' developer.allizom.org bcd.developer.allizom.org bcd.developer.mozilla.org updates.developer.allizom.org updates.developer.mozilla.org https://incoming.telemetry.mozilla.org https://observatory-api.mdn.allizom.net https://observatory-api.mdn.mozilla.net telemetry.transcend.io telemetry.us.transcend.io transcend-cdn.com https://api.github.com/search/issues https://api.stripe.com; font-src 'self'; frame-src 'self' mdn.github.io *.mdnplay.dev *.mdnyalp.dev *.play.test.mdn.allizom.net https://v2.scrimba.com https://scrimba.com jsfiddle.net www.youtube-nocookie.com codepen.io survey.alchemer.com https://js.stripe.com; img-src 'self' data: *.githubusercontent.com *.gravatar.com mozillausercontent.com firefoxusercontent.com profile.stage.mozaws.net profile.accounts.firefox.com developer.mozilla.org mdn.dev wikipedia.org upload.wikimedia.org https://mdn.github.io/shared-assets/ https://mdn.dev/; manifest-src 'self'; media-src 'self' archive.org videos.cdn.mozilla.net https://mdn.github.io/shared-assets/; child-src 'self'; worker-src 'self'; |
| X-guploader-uploadid
| AJjja9YvOk3ZEqu1o9MHqKfTvhGRml4_joFkdoZZ22QbXCCpA8lwwki8zq8HNiFb8SbN-rlpd_DxaJk |
| X-frame-options
| DENY |
| X-goog-stored-content-length
| 118736 |
| X-content-type-options
| nosniff |
| X-goog-meta-goog-reserved-file-mtime
| 1787185877 |
| Strict-transport-security
| max-age=63072000 |
| Via
| 1.1 google, 1.1 varnish, 1.1 varnish |
| X-goog-generation
| 1787186781503790 |
| Expires
| Thu, 20 Aug 2026 02:11:03 GMT |
| Last-modified
| Thu, 20 Aug 2026 00:46:21 GMT |
| Cache-control
| public, max-age=3600 |
| Content-encoding
| gzip |
| Accept-ranges
| bytes |
| Date
| Thu, 20 Aug 2026 03:21:54 GMT |
| Age
| 1099 |
| X-served-by
| cache-par-lfpb1150054-PAR, cache-par-lfpb1150054-PAR, cache-par-lfpb1150082-PAR |
| X-cache
| MISS, HIT |
| X-cache-hits
| 0, 1 |
| X-timer
| S1787196114.407415,VS0,VE1 |
| Vary
| Accept-Encoding |
| Content-length
| 16583 |
Meta Tags
| Viewport | width=device-width, initial-scale=1.0 |
| Description | The MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps. |
| Position | 1 |
Etag "34b29c866c02c08f4298d4ab4cc2e18b"
Content-type text/html
Server Google Frontend
X-goog-stored-content-encoding identity
Referrer-policy strict-origin-when-cross-origin
X-goog-metageneration 1
X-goog-storage-class STANDARD
X-cloud-trace-context 846ec1d84ae27abdb4200a491a46be66
X-goog-hash crc32c=Aa8Tlw==, md5=NLKchmwCwI9CmNSrTMLhiw==
Content-security-policy default-src 'self'; script-src 'report-sample' 'self' 'wasm-unsafe-eval' assets.codepen.io production-assets.codepen.io https://js.stripe.com transcend-cdn.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; script-src-elem 'report-sample' 'self' 'wasm-unsafe-eval' assets.codepen.io production-assets.codepen.io https://js.stripe.com transcend-cdn.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; style-src 'report-sample' 'self' 'unsafe-inline' transcend-cdn.com; object-src 'none'; base-uri 'self'; connect-src 'self' developer.allizom.org bcd.developer.allizom.org bcd.developer.mozilla.org updates.developer.allizom.org updates.developer.mozilla.org https://incoming.telemetry.mozilla.org https://observatory-api.mdn.allizom.net https://observatory-api.mdn.mozilla.net telemetry.transcend.io telemetry.us.transcend.io transcend-cdn.com https://api.github.com/search/issues https://api.stripe.com; font-src 'self'; frame-src 'self' mdn.github.io *.mdnplay.dev *.mdnyalp.dev *.play.test.mdn.allizom.net https://v2.scrimba.com https://scrimba.com jsfiddle.net www.youtube-nocookie.com codepen.io survey.alchemer.com https://js.stripe.com; img-src 'self' data: *.githubusercontent.com *.gravatar.com mozillausercontent.com firefoxusercontent.com profile.stage.mozaws.net profile.accounts.firefox.com developer.mozilla.org mdn.dev wikipedia.org upload.wikimedia.org https://mdn.github.io/shared-assets/ https://mdn.dev/; manifest-src 'self'; media-src 'self' archive.org videos.cdn.mozilla.net https://mdn.github.io/shared-assets/; child-src 'self'; worker-src 'self';
X-guploader-uploadid AJjja9YvOk3ZEqu1o9MHqKfTvhGRml4_joFkdoZZ22QbXCCpA8lwwki8zq8HNiFb8SbN-rlpd_DxaJk
X-frame-options DENY
X-goog-stored-content-length 118736
X-content-type-options nosniff
X-goog-meta-goog-reserved-file-mtime 1787185877
Strict-transport-security max-age=63072000
Via 1.1 google, 1.1 varnish, 1.1 varnish
X-goog-generation 1787186781503790
Expires Thu, 20 Aug 2026 02:11:03 GMT
Last-modified Thu, 20 Aug 2026 00:46:21 GMT
Cache-control public, max-age=3600
Content-encoding gzip
Accept-ranges bytes
Date Thu, 20 Aug 2026 03:21:54 GMT
Age 1099
X-served-by cache-par-lfpb1150054-PAR, cache-par-lfpb1150054-PAR, cache-par-lfpb1150082-PAR
X-cache MISS, HIT
X-cache-hits 0, 1
X-timer S1787196114.407415,VS0,VE1
Vary Accept-Encoding
Content-length 16583
