Ui.adsabs.harvard.edu - SEO Checker

Overview of the SEO Check
Meta information
98% 
Page quality
52% 
Page structure
79% 
Link structure
0% 
Server
40% 
External factors
100% 
SEO Score
Response time
0.49 s
File size
8.90 kB
Words
19
Media files
0
Number of links
1 internal / 0 external

Task list of SEO Improvements

Meta specifications

Title
(Critically important)
Astrophysics Data System
The length of the page title is perfect. (237 pixels out of 580 max pixel length)
There are no duplicate words in the title
Meta description
(Critically important)
A powerful, streamlined new Astrophysics Data System
The length of the meta description is perfect. (339 pixels out of 1000 max pixel length)
Crawlability
(Critically important)
There are no problems in accessing the website.
Canonical URL
(Important)
No canonical link is specified.
Language
(Somewhat important)
Language defined in HTML: en
Server location: United States of America
The following language is defined by HTML: en
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,user-scalable=no
google-site-verificationXxQuw38lagr8-TgtCyhAMP_6ELS9dy35fgrqo9dxw3o
descriptionA powerful, streamlined new Astrophysics Data System
apple-mobile-web-app-titleAstrophysics Data System
application-nameAstrophysics Data System
msapplication-TileColor#ffc40d
theme-color#ffffff
langen
X-UA-CompatibleIE=edge,chrome=1
charsetutf-8

Automatically check ui.adsabs.harvard.edu including all subpages at once!

Try for free
Guaranteed free of charge during trial period.

Page quality

Content
(Critically important)
There are only 19 words on this page. Use at least 250 words to provide useful information.
Words from the H1 heading are not used in the page content.
No paragraphs were detected.
21.1% of the text are stop words.
Keywords used in the page title are also used in the page content. That's good!
No placeholders texts or images were found.
Frames
(Critically important)
This page does not use a frameset.
Mobile optimization
(Somewhat important)
A viewport "width=device-width,user-scalable=no" 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 6 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

No media files were found.

Page structure

H1 heading
(Critically important)
astrophysics data system
The H1 heading is perfect.
Headings
(Important)
The structure of headings is missing one or more levels. Do not skip heading levels.

Heading structure

Heading levelContent
H1 astrophysics data system
H3 Loading ADS | Click here to switch to Basic HTML (for slow connections/low resources)
Baselink: /
This page seems to be an entry page, because only very few links were found.
Every linktext is unique.
None of the anchor texts is too long.
All internal links are not using dynamic parameters.
There are no external links on this page.
LinkAttributesAnchor text
/coreSubdomain Click here to switch to Basic HTML

Server configuration

HTTP redirects
(Critically important)
This page redirects to "https://ui.adsabs.harvard.edu/"
HTTP header
(Important)
The HTML page should be transferred using GZip compression.
No X-Powered HTTP header is sent.
Performance
(Somewhat important)
The page response time of 0.49 seconds is longer than the recommended limit of 0.4 seconds. A high response time unnecessarily slows down search engine crawling and results in bad user experience as well.
The file size of the HTML document is fine (9 kB).

HTTP Response Header

NameValue
dateFri, 04 Jul 2025 22:57:58 GMT
content-typetext/html
content-length9101
last-modifiedMon, 16 Jun 2025 12:45:54 GMT
cache-controlmax-age=0, no-cache, no-store, must-revalidate
pragmano-cache
x-frame-optionsSAMEORIGIN
accept-rangesbytes
statuscode200
http_versionHTTP/2

External factors

This page is referenced by wikipedia.
This website has excellent links from other websites.
This page has backlinks from 2,302 referring domains.
This page has 292,116 backlinks.
This page has backlinks from 1,342 different ip addresses.

Robots.txt

Sitemap: https://ui.adsabs.harvard.edu/sitemap/sitemap_index.xml

User-agent: *
Disallow: /v1/
Disallow: /resources
Disallow: /core
Disallow: /tugboat
Disallow: /link_gateway/
Disallow: /search/
Disallow: /execute-query/
Disallow: /status

Allow: /help/
Allow: /about/
Allow: /blog/

# there may be a more elegant way to do this, but I fear that if we just use a 
# single regexp such as /abs/*/* we may miss out on indexing links containing
# DOIs or arXiv ids, so we do it the pedantic way
Allow: /abs/
Disallow: /abs/*/citations
Disallow: /abs/*/references
Disallow: /abs/*/coreads
Disallow: /abs/*/similar
Disallow: /abs/*/toc
Disallow: /abs/*/graphics
Disallow: /abs/*/metrics
Disallow: /abs/*/exportcitation

User-agent: AI2Bot
Disallow: /

User-agent: Ai2Bot-Dolma
Disallow: /

User-agent: Amazonbot
Disallow: /

User-agent: anthropic-ai
Disallow: /

User-agent: Applebot
Disallow: /

User-agent: Applebot-Extended
Disallow: /

User-agent: Brightbot 1.0
Disallow: /

User-agent: Bytespider
Disallow: /

User-agent: CCBot
Disallow: /

User-agent: Claude-Web
Disallow: /

User-agent: ClaudeBot
Disallow: /

User-agent: cohere-training-data-crawler
Disallow: /

User-agent: Crawlspace
Disallow: /

User-agent: Diffbot
Disallow: /

User-agent: FacebookBot
Disallow: /

User-agent: FriendlyCrawler
Disallow: /

User-agent: Google-Extended
Disallow: /

User-agent: GoogleOther
Disallow: /

User-agent: GoogleOther-Image
Disallow: /

User-agent: GoogleOther-Video
Disallow: /

User-agent: GPTBot
Disallow: /

User-agent: iaskspider/2.0
Disallow: /

User-agent: ICC-Crawler
Disallow: /

User-agent: ImagesiftBot
Disallow: /

User-agent: img2dataset
Disallow: /

User-agent: ISSCyberRiskCrawler
Disallow: /

User-agent: Kangaroo Bot
Disallow: /

User-agent: Meta-ExternalAgent
Disallow: /

User-agent: Meta-ExternalFetcher
Disallow: /

User-agent: omgili
Disallow: /

User-agent: omgilibot
Disallow: /

User-agent: PanguBot
Disallow: /

User-agent: Scrapy
Disallow: /

User-agent: SemrushBot-OCOB
Disallow: /

User-agent: SemrushBot-SWA
Disallow: /

User-agent: Sidetrade indexer bot
Disallow: /

User-agent: Timpibot
Disallow: /

User-agent: VelenPublicWebCrawler
Disallow: /

User-agent: Webzio-Extended
Disallow: /

User-agent: YouBot
Disallow: /

Search preview

ui.adsabs.harvard.edu
Astrophysics Data System
A powerful, streamlined new Astrophysics Data System

Most important keywords

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

KeywordResultRecheck
astrophysics73%Check
data73%Check
system73%Check
astrophysics data system73%Check
ADS50%Check
loading38%Check
Click38%Check
switch38%Check
Basic38%Check
HTML38%Check

Automatically check ui.adsabs.harvard.edu including all subpages at once!

Try for free
Guaranteed free of charge during trial period.

Cookie Policy

We use cookies to make our site work and also for analytics and advertising purposes. You can enable or disable optional cookies as desired. See the following links for more information.

We need these so the site can function properly

So we can better understand how visitors use our website

So we can serve you tailored ads and promotions