Developer.mozilla.org - SEO Checker

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Overview of the SEO Check
Meta information
87% 
Page quality
83% 
Page structure
100% 
Link structure
82% 
Server
100% 
External factors
100% 
SEO Score
Response time
0.27 s
File size
45.00 kB
Words
613
Media files
1
Number of links
64 internal / 33 external

Task list of SEO Improvements

Meta specifications

Title
(Critically important)
MDN Web Docs
The page title is too short. (143 pixels of 580 max pixel length) Optimize title
There are no duplicate words in the title
Meta description
(Critically important)
The MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps.
The length of the meta description is perfect. (958 pixels out of 1000 max pixel length)
Crawlability
(Critically important)
There are no problems in accessing the website.
Canonical URL
(Important)
https://developer.mozilla.org/en-US/
There is a valid canonical link specified.
Language
(Somewhat important)
Language detected in text: en
Language defined in HTML: en-us
Server location: United States of America
The following language is defined by HTML: en-us
Alternate/Hreflang Links
(Somewhat important)
There are no alternate links specified on this page.
Other meta tags
(Somewhat important)
There is no rel next meta tag on this page.
There is no rel prev meta tag on this page.
Domain
(Somewhat important)
This page is hosted on a subdomain. Use a top level domain for better SEO results.
The domain does not contain non-latin characters.
Page URL
(Somewhat important)
No parameters were found in the URL.
No session ID was found in the URL.
The URL does not have too many subdirectories.
Charset encoding
(Somewhat important)
The character encoding is not specified in the HTTP header.
The charset encoding (UTF-8) is set correctly.
Doctype
(Nice to have)
The doctype HTML 5 is set correctly.
The doctype is placed at first in the HTML code.
Favicon
(Nice to have)
The favicon is linked correctly.

Meta tags

NameValue
viewportwidth=device-width,initial-scale=1
theme-color#ffffff
descriptionThe MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps.
langen-us
twitter:cardsummary_large_image
twitter:creatorMozDevNet
og:urlhttps://developer.mozilla.org/en-US/
og:titleMDN Web Docs
og:typewebsite
og:localeen_US
og:descriptionThe MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps.
og:imagehttps://developer.mozilla.org/mdn-social-share.d893525a4fb5fb1f67a2.png
og:image:typeimage/png
og:image:height1080
og:image:width1920
og:image:altThe MDN Web Docs logo, featuring a blue accent color, displayed on a solid black background.
og:site_nameMDN Web Docs
charsetutf-8

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Page quality

Content
(Critically important)
Some words from the page title are not used within the pages content
This page contains 613 words. That's ok.
23.3% of the text are stop words.
Words from the H1 heading are used in the page content.
The page contains a listing, which indicates a good text layout.
6 paragraphs were found on this page.
No placeholders texts or images were found.
There are no duplicates on the site.
The average number of words per sentence of 18.58 words is good.
Frames
(Critically important)
This page does not use a frameset.
Mobile optimization
(Somewhat important)
A viewport "width=device-width,initial-scale=1" is provided.
At least one Apple touch icon is specified.
Bold and strong tags
(Somewhat important)
The usage of strong and bold tags is perfect. We recommend the use of up to 12 tags for this page.
Image SEO
(Somewhat important)
Alt text (alternative text) is correctly used on all found images.
Social Networks
(Nice to have)
There are only a few social sharing widgets on the page. Make your website popular in social networks with social sharing widgets.
Additional markup
(Nice to have)
No additional page markup was found.
HTTPS
(Somewhat important)
This website uses HTTPS to protect privacy and integrity of the exchanged data.
All included files are also transferred via HTTPS.

Media list

URLAlt attributeTitle
...mdn_contributor.14a24dcfda486f000754.pngTiled Mozilla Logo

Page structure

H1 heading
(Critically important)
Resources for Developers, by Developers
The H1 heading is perfect.
Headings
(Important)
The heading structure is perfect.

Heading structure

Heading levelContent
H1 Resources for Developers, by Developers
H2 Featured articles
H2 Latest news
H2 Recent contributions
H2 MDN
H2 Support
H2 Our communities
H2 Developers
H3 JavaScript Temporal is coming
H3 CSS anchor positioning
H3 Using the View Transition API
H3 Temporal
H3 Contributor Spotlight
Some anchor texts are used more than once.
1 links don't have an anchor text.
The number of internal links is ok.
None of the anchor texts is too long.
All internal links are not using dynamic parameters.
There are too many external links (33) on this page.

Found links on this page

LinkAttributesAnchor text
/en-US/Anchor Skip to main content
/en-US/Anchor Skip to search
/en-US/No Text
/en-US/docs/WebReferences
/en-US/docs/WebOverview / Web Technology Web technology reference for developers
/en-US/docs/Web/HTMLHTML Structure of content on the web
/en-US/docs/Web/CSSCSS Code used to describe document style
/en-US/docs/Web/JavaScriptJavaScript General-purpose scripting language
/en-US/docs/Web/HTTPHTTP Protocol for transmitting web resources
/en-US/docs/Web/APIWeb APIs Interfaces for building web applications
/en-US/docs/Mozilla/Add-ons/We...Web Extensions Developing extensions for web browsers
/en-US/docs/Web/AccessibilityAccessibility Build web projects usable for all
/en-US/docs/WebWeb Technology Web technology reference for developers
/en-US/docs/Learn_web_developmentLearn
/en-US/docs/Learn_web_developmentOverview / MDN Learning Area Learn web development
/en-US/docs/Learn_web_developmentMDN Learning Area Learn web development
/en-US/docs/Learn_web_developm...HTML Learn to structure web content with HTML
/en-US/docs/Learn_web_developm...CSS Learn to style content using CSS
/en-US/docs/Learn_web_developm...JavaScript Learn to run scripts in the browser
/en-US/docs/Learn_web_developm...Accessibility Learn to make the web accessible to all
/en-US/plusPlus
/en-US/plusOverview A customized MDN experience
/en-US/plus/ai-helpAI Help Get real-time assistance and support
/en-US/plus/updatesUpdates All browser compatibility updates at a glance
/en-US/plus/docs/features/over...Documentation Learn how to use MDN Plus
/en-US/plus/docs/faqFAQ Frequently asked questions about MDN Plus
/en-US/curriculum/Curriculum New
/en-US/blog/Blog
/en-US/playPlayground Write, test and share your code
/en-US/observatoryHTTP Observatory Scan a website for free
/en-US/plus/ai-helpText duplicate AI Help Get real-time assistance and support
/users/fxa/login/authenticate/...Nofollow Log in
/users/fxa/login/authenticate/...Nofollow Sign up for free
/en-US/docs/Web/CSSCSS
/en-US/docs/Web/HTMLHTML
/en-US/docs/Web/JavaScriptJavaScript
/en-US/blog/Text duplicate Blog
/en-US/blog/javascript-tempora...JavaScript Temporal is coming
/en-US/docs/Web/CSSText duplicate CSS
/en-US/docs/Web/CSS/CSS_anchor...CSS anchor positioning
/en-US/docs/Web/APIWeb APIs
/en-US/docs/Web/API/View_Trans...Using the View Transition API
/en-US/docs/Web/JavaScriptText duplicate JavaScript
/en-US/docs/Web/JavaScript/Ref...Temporal
/en-US/blog/mdn-2024-content-p...MDN 2024 content projects
/en-US/blog/developer.mozilla.org
/en-US/blog/curriculum-learn-w...A new learning experience on MDN
/en-US/blog/Text duplicate developer.mozilla.org
/en-US/blog/new-community-page/Introducing the new MDN Community page
/en-US/blog/Text duplicate developer.mozilla.org
https://github.com/mdn/content...External Scrimba survey
https://github.com/mdn/contentExternal mdn/content
https://github.com/mdn/content...External Replace Local Font Access API demo glitch links
https://github.com/mdn/contentExternal Text duplicate mdn/content
https://github.com/mdn/content...External Fix content issues
https://github.com/mdn/contentExternal Text duplicate mdn/content
https://github.com/mdn/content...External Update file system API glitch demo links
https://github.com/mdn/contentExternal Text duplicate mdn/content
https://github.com/mdn/transla...External [ja] Update Glossary/Slug
https://github.com/mdn/transla...External mdn/translated-content
https://github.com/mdn/transla...External [zh-tw] auto-fix content issues
https://github.com/mdn/transla...External Text duplicate mdn/translated-content
https://github.com/mdn/transla...External zh-cn: translate CSS Declaration Block topic
https://github.com/mdn/transla...External Text duplicate mdn/translated-content
https://github.com/mdn/transla...External [zh-TW]: update API `MediaQueryList`
https://github.com/mdn/transla...External Text duplicate mdn/translated-content
https://github.com/mdn/content...External CSS best practice: always specify generic font family as fallback
https://github.com/mdn/contentExternal Text duplicate mdn/content
/en-US/community/spotlight/yas...Yash Raj Bharti
/en-US/communityGet involved →
https://developer.mozilla.org/No Text
https://bsky.app/profile/devel...New window External MDN on Bluesky
https://mastodon.social/@mdnNew window External MDN on Mastodon
https://twitter.com/mozdevnetNew window External MDN on X (formerly Twitter)
https://github.com/mdn/New window External MDN on GitHub
/en-US/blog/rss.xmlNew window MDN Blog RSS Feed
/en-US/aboutAbout
/en-US/blog/Text duplicate Blog
https://www.mozilla.org/en-US/...New window External Subdomain Careers
/en-US/advertisingAdvertise with us
https://support.mozilla.org/pr...External Subdomain Product help
/en-US/docs/MDN/Community/IssuesReport an issue
/en-US/communityMDN Community
https://discourse.mozilla.org/...New window External Subdomain MDN Forum
/discordNew window MDN Chat
/en-US/docs/WebWeb Technologies
/en-US/docs/LearnLearn Web Development
/en-US/plusMDN Plus
https://hacks.mozilla.org/New window External Subdomain Hacks Blog
https://www.mozilla.org/New window External Subdomain No Text
https://www.mozilla.org/privac...New window External Subdomain Website Privacy Notice
https://www.mozilla.org/privac...New window External Subdomain Anchor Cookies
https://www.mozilla.org/about/...New window External Subdomain Legal
https://www.mozilla.org/about/...New window External Subdomain Community Participation Guidelines
https://www.mozilla.org/New window External Subdomain Mozilla Corporation’s
https://foundation.mozilla.org/New window External Subdomain Mozilla Foundation
/en-US/docs/MDN/Writing_guidel...a Creative Commons license

Server configuration

HTTP redirects
(Critically important)
This page redirects to "https://developer.mozilla.org/en-US/"
HTTP header
(Important)
No X-Powered HTTP header is sent.
The web server transmits the web page (HTML) in compressed form.
Performance
(Somewhat important)
The page response time is excellent with 0.27 seconds.
The file size of the HTML document is fine (45 kB).

HTTP Response Header

NameValue
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x-goog-metageneration1
x-goog-stored-content-encodingidentity
x-goog-stored-content-length46033
x-goog-meta-goog-reserved-file-mtime1751761538
x-goog-hashcrc32c=wnXyRg==, md5=zr6eMcROcoLUGK4Ou1or+g==
x-goog-storage-classSTANDARD
accept-rangesnone
expiresSun, 06 Jul 2025 07:53:55 GMT
cache-controlpublic, max-age=3600
last-modifiedSun, 06 Jul 2025 00:45:43 GMT
etagW/"cebe9e31c44e7282d418ae0ebb5a2bfa"
content-typetext/html
age1233
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x-content-type-optionsnosniff
strict-transport-securitymax-age=63072000
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External factors

This page is referenced by wikipedia.
This website has excellent links from other websites.
This page has backlinks from 3,361 referring domains.
This page has 389,408 backlinks.
This page has backlinks from 2,378 different ip addresses.

Links from Wikipedia

You can find more links using Wikipedia search

Robots.txt

User-agent: *
Sitemap: https://developer.mozilla.org/sitemap.xml

Disallow: /api/
Disallow: /*/files/
Disallow: /media

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Search preview

developer.mozilla.org › en-US
MDN Web Docs
The MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps.

Most important keywords

Following keywords were found. You can check the keyword optimization of this page for each keyword.

KeywordResultRecheck
MDN63%Check
MDN Web60%Check
Web58%Check
Web Resources54%Check
developers52%Check
Web Technologies52%Check
Web APIs52%Check
open web52%Check
CSS50%Check
API50%Check
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