Ncbi.nlm.nih.gov - SEO Checker

Overview of the SEO Check
Meta information
80% 
Page quality
53% 
Page structure
43% 
Link structure
100% 
Server
88% 
External factors
100% 
SEO Score
Response time
0.65 s
File size
37.00 kB
Words
266
Media files
10
Number of links
43 internal / 25 external

Task list of SEO Improvements

Meta specifications

Title
(Critically important)
National Center for Biotechnology Information
The length of the page title is perfect. (409 pixels out of 580 max pixel length)
There are no duplicate words in the title
Meta description
(Critically important)
The meta description is missing.
Crawlability
(Critically important)
There are no problems in accessing the website.
Canonical URL
(Important)
No canonical link is specified.
Language
(Somewhat important)
Language detected in text: en
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)
The domain is no subdomain.
The domain length is good.
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
ncbiexpanderminHeight: 70
ncbi_appguide
ncbi_pdidHomePage
langen
og:imagehttps://www.ncbi.nlm.nih.gov/corehtml/logo256.gif
og:image:secure_url/corehtml/logo256.gif
Content-Typetext/html; charset=UTF-8

Test up to 1.000 webpages of ncbi.nlm.nih.gov with our free plan!

Try For Free
No trial. It's just free!

Page quality

Content
(Critically important)
There are only 266 words on this page. Good pages should have about 800 words of useful content.
The average number of words per sentence of 8 words is low.
21.1% of the text are stop words.
Keywords used in the page title are also used in the page content. That's good!
The page contains a listing, which indicates a good text layout.
3 paragraphs were found on this page.
No placeholders texts or images were found.
There are no duplicates on the site.
Frames
(Critically important)
This page does not use a frameset.
Mobile optimization
(Somewhat important)
No viewpoint tag is provided.
No 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)
6 images have no alt attribute. The content of alt attributes is used by search engines.
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.

Page structure

H1 heading
(Critically important)
NCBI
Too many H1 headings
The H1 heading consists of only one word. There should be more information given.
The H1 heading is too short (4 characters). It should be at least 20 Characters long.
Headings
(Important)
The heading structure is perfect.

Heading structure

Heading levelContent
H1 NCBI
H1 Welcome to NCBI
H2 National Center for Biotechnology Information
H2 Submit
H2 Download
H2 Learn
H2 Develop
H2 Analyze
H2 Research
H3 Popular Resources
H4 Account
The number of internal links is ok.
Every linktext is unique.
None of the anchor texts is too long.
All internal links are not using dynamic parameters.
There are 25 external links on this page.
LinkAttributesAnchor text
https://www.ncbi.nlm.nih.gov/IMG-ALT NIH NLM Logo
https://account.ncbi.nlm.nih.gov/External Subdomain Log in
/myncbi/Dashboard
/myncbi/collections/bibliography/Publications
/account/settings/Account settings
/account/signout/Log out
/guide/browsers/Subdomain Anchor Access keys
https://www.ncbi.nlm.nih.gov/Subdomain NCBI Homepage
/myncbi/MyNCBI Homepage
https://www.ncbi.nlm.nih.gov/Anchor Main Content
https://www.ncbi.nlm.nih.gov/NCBI
A-TITLE NCBI
/home/about/About the NCBI
/home/about/mission/Mission
/home/about/structure/Organization
https://ncbiinsights.ncbi.nlm....External Subdomain NCBI News & Blog
https://submit.ncbi.nlm.nih.gov/External Subdomain Submit Deposit data or manuscripts into NCBI databases Submit Icon
/home/download/Download Transfer NCBI data to your computer Download Icon
/home/learn/Learn Find help documents, attend a class or watch a tutorial Books Icon
/home/develop/Develop Use NCBI APIs and code libraries to build applications Develop Icon
/home/analyze/Analyze Identify an NCBI tool for your data analysis task Graph Icon
/research/Research Explore NCBI research and collaborative projects Microscope Icon
https://www.ncbi.nlm.nih.gov/NCBI Home
/guide/sitemap/Resource List (A-Z)
/guide/all/All Resources
/guide/chemicals-bioassays/Chemicals & Bioassays
/guide/data-software/Data & Software
/guide/dna-rna/DNA & RNA
/guide/domains-structures/Domains & Structures
/guide/genes-expression/Genes & Expression
/guide/genetics-medicine/Genetics & Medicine
/guide/genomes-maps/Genomes & Maps
/guide/homology/Homology
/guide/literature/Literature
/guide/proteins/Proteins
/guide/sequence-analysis/Sequence Analysis
/guide/taxonomy/Taxonomy
/guide/training-tutorials/Training & Tutorials
/guide/variation/Variation
/pubmed/PubMed
/books/Bookshelf
https://www.ncbi.nlm.nih.gov/pmc/PubMed Central
https://blast.ncbi.nlm.nih.gov/External Subdomain BLAST
/nucleotide/Nucleotide
/genome/Genome
https://www.ncbi.nlm.nih.gov/snp/SNP
/gene/Gene
/protein/Protein
https://pubchem.ncbi.nlm.nih.gov/External Subdomain PubChem
https://twitter.com/ncbiExternal No Text
https://www.facebook.com/ncbi.nlmExternal Subdomain No Text
https://www.linkedin.com/compa...External Subdomain No Text
https://github.com/ncbiExternal No Text
https://ncbiinsights.ncbi.nlm....External Subdomain No Text
https://www.nlm.nih.gov/social...External Subdomain Connect with NLM
https://twitter.com/NLM_NIHNew window External No Text
https://www.facebook.com/natio...New window External Subdomain No Text
https://www.youtube.com/user/N...New window External Subdomain No Text
https://www.google.com/maps/pl...New window External Subdomain 8600 Rockville Pike Bethesda, MD 20894
https://www.nlm.nih.gov/web_po...External Subdomain Web Policies
https://www.nih.gov/institutes...External Subdomain FOIA
https://www.hhs.gov/vulnerabil...External Subdomain HHS Vulnerability Disclosure
https://support.nlm.nih.gov/External Subdomain Help
https://www.nlm.nih.gov/access...External Subdomain Accessibility
https://www.nlm.nih.gov/career...External Subdomain Careers
https://www.nlm.nih.gov/External Subdomain NLM
https://www.nih.gov/External Subdomain NIH
https://www.hhs.gov/External Subdomain HHS
https://www.usa.gov/External Subdomain USA.gov

Server configuration

HTTP redirects
(Critically important)
This page redirects to "https://www.ncbi.nlm.nih.gov/"
HTTP header
(Important)
No X-Powered HTTP header is sent.
This page uses GZip for compressed data transmission.
Performance
(Somewhat important)
The page response time of 0.65 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 (37 kB).

HTTP Response Header

NameValue
strict-transport-securitymax-age=31536000; includeSubDomains; preload
referrer-policyorigin-when-cross-origin
content-security-policyupgrade-insecure-requests
caf2.0.1
accept-rangesbytes
varyAccept-Encoding
content-encodinggzip
x-ua-compatibleIE=Edge
x-xss-protection1; mode=block
x-frame-optionsSAMEORIGIN
content-length9154
content-typetext/html
dateTue, 11 Jun 2024 04:46:44 GMT
serverApache
statuscode200
http_versionHTTP/2

External factors

Blacklists
(Nice to have)
This website is not classified "for adult only".
This page is referenced by wikipedia.
This website has excellent links from other websites.
This page has backlinks from 548,459 referring domains.
This page has 632,275,261 backlinks.
This page has backlinks from 231,313 different ip addresses.
Facebook popularity
(Somewhat important)
The page has 141706 shares and comments on Facebook.

Robots.txt

# robots.txt - robot exclusion file - back-end server version - no robots!
# ========================================================================
User-agent: htdig/3.1.6
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /mailman
Disallow: /myncbi
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /blast/BlastAlign.cgi 
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/articles/
Disallow: /pmc/ivip/
Disallow: /pmc/articlerender.fcgi
Disallow: /pmc/pagerender.fcgi
Disallow: /pmc/picrender.fcgi
Disallow: /pmc/tocrender.fcgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /sars-cov-2

User-agent: Baiduspider
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /mailman
Disallow: /myncbi
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /blast/BlastAlign.cgi
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/articles/
Disallow: /pmc/ivip/
Disallow: /pmc/articlerender.fcgi
Disallow: /pmc/pagerender.fcgi
Disallow: /pmc/picrender.fcgi
Disallow: /pmc/tocrender.fcgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /sars-cov-2

User-agent: Googlebot
Disallow: /cgi-bin
Disallow: /stat
Disallow: /COG
Disallow: /mailman
Disallow: /sutils
Disallow: /entrez/viewer.fcgi
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /SAGE
Disallow: /SNP
Disallow: /snp
Disallow: /IEB/ToolBox/SB
Disallow: /Structure/dgs
Disallow: /Structure/VA
Disallow: /Structure/cblast/cblast.cgi
Disallow: /Coffeebreak
Disallow: /gorf
Disallow: /mapview
Disallow: /myncbi
Disallow: /blast/BlastAlign.cgi 
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /entrez/eutils
Disallow: /entrez/utils
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/*/bin/
Disallow: /pmc/*/pdf/
Disallow: /pmc/*/equ/
Disallow: /pmc/*.cgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /clone/library/genomic/organisms
Disallow: /sars-cov-2
Allow: /portal/portal3rc.fcgi/*/*.js
Allow: /portal/portal3rc.fcgi/*/*.css

User-agent: Teleport Pro
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /myncbi
Disallow: /mailman
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /blast/BlastAlign.cgi 
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/articles/
Disallow: /pmc/ivip/
Disallow: /pmc/articlerender.fcgi
Disallow: /pmc/pagerender.fcgi
Disallow: /pmc/picrender.fcgi
Disallow: /pmc/tocrender.fcgi
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /sars-cov-2

User-agent: yacybot
Disallow: * 

User-agent: Browsershots
Disallow:
Disallow: /sars-cov-2

User-agent: Slurp
Crawl-delay: 1
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /myncbi
Disallow: /mailman
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /blast/BlastAlign.cgi
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /SAGE
Disallow: /SNP
Disallow: /snp
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/*/bin/
Disallow: /pmc/*/pdf/
Disallow: /pmc/*/equ/
Disallow: /pmc/*.cgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /sars-cov-2

User-agent: Twitterbot
Disallow: *
Allow: /pmc/articles
Allow: /books/NBK*

User-agent: Exabot
Disallow: /Structure
Disallow: /mailman
Disallow: /stat
Disallow: /sars-cov-2


User-agent: bingbot
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /myncbi
Disallow: /mailman
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /SAGE
Disallow: /SNP
Disallow: /snp
Disallow: /blast/BlastAlign.cgi
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/*/bin/
Disallow: /pmc/*/pdf/
Disallow: /pmc/*/equ/
Disallow: /pmc/*.cgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /clone/library/genomic/organisms
Disallow: /sars-cov-2
Allow: /portal/portal3rc.fcgi/*/*.js
Allow: /portal/portal3rc.fcgi/*/*.css

User-agent: *
Crawl-delay: 5
Disallow: /cgi-bin
Disallow: /stat
Disallow: /entrez
Disallow: /COG
Disallow: /Entrez
Disallow: /myncbi
Disallow: /mailman
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /SAGE
Disallow: /SNP
Disallow: /snp
Disallow: /blast/BlastAlign.cgi 
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/articles/
Disallow: /pmc/ivip/
Disallow: /pmc/articlerender.fcgi
Disallow: /pmc/pagerender.fcgi
Disallow: /pmc/picrender.fcgi
Disallow: /pmc/tocrender.fcgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /clone/library/genomic/organisms
Disallow: /sars-cov-2
Allow: /portal/portal3rc.fcgi/*/*.js
Allow: /portal/portal3rc.fcgi/*/*.css

Sitemap: https://www.ncbi.nlm.nih.gov/Structure/sitemaps/cdd/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/Structure/sitemaps/genome/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/Structure/sitemaps/mmdb/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/Structure/sitemaps/sparcle/sitemap.xml
Sitemap: https://www.ncbi.nlm.nih.gov/Traces/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/core/assets/osiris/files/sitemap.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=assembly/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=biosystems/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=books/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=cdd/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=clinvar/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=gene/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=gtr/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=medgen/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=mesh/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=ncbi/sitemap.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=nlmcatalog/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=orgtrack/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=pmc/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=snp/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=sra/sitemap_index.xml

Search preview

Most important keywords

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

KeywordResultRecheck
NCBI68%Check
gov54%Check
Log54%Check
National50%Check
Center50%Check
Biotechnology50%Check
National Center50%Check
NLM50%Check
Biotechnology Information50%Check
information49%Check

Test up to 1.000 webpages of ncbi.nlm.nih.gov with our free plan!

Try For Free
No trial. It's just free!

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