Technical SEO List

indexability

Issues that can block or complicate crawling and indexing of website pages by Googlebot.

Canonical is missing
H2 has other tags inside
H1 has other tags inside
Page contains a form with a GET method
Page has content-type other than text/html
Meta nofollow pages
Meta noindex pages
Canonical to non-200
Canonical is empty
Canonical from HTTP to HTTPS
Canonical from HTTPS to HTTP
Double slash in URL
Mismatched canonical tag in HTML and HTTP header
Noscript in head contains invalid HTML elements
Canonical outside of head
Canonical points to a disallowed URL
Canonical points to a noindex URL
Canonical points to another canonicalized URL
Canonicalized URL is noindex, nofollow
More than one <body> tag on page
More than one </body> tag on page
More than one </head> tag on page
More than one </html> tag on page
More than one <head> tag on page
More than one <html> tag on page
Page has content after </html>
</body> tag is missing
</head> tag is missing
</html> tag is missing
<head> tag is missing
<body> tag is missing
<html> tag is missing
Page has disallowed CSS files
Page has disallowed images
Page has disallowed JavaScript files
Page has no declared character encoding
Mismatched nofollow directives in HTML and header
Mismatched noindex directives in HTML and header
Page has content before <!doctype html>
Noindex in HTML and HTTP header
Nofollow in HTML and HTTP header
Canonical is a relative URL
Meta robots found outside of <head>
Multiple base URLs
Multiple canonical tags
Multiple noindex directives
Multiple, mismatched base URLs
Base URL malformed or empty
Canonical ≠ URL
Disallowed by robots.txt
Noindex follow page
More than three parameters in URL
Page contains rel=sponsored attributes
Error page responds 404 status code
Site has a valid robots.txt file
Home page is open for scanning by search engine robots in robots.txt
Home page is open for indexing in search engines

content relevance

Issues that can reduce the relevance of content to search intent missing, empty or repeatable content tags, outdated content etc.

Missing alt text
Description is missing
Page has no strong importance elements
Page has alt tags with one word
Text to code ratio < 10%
Title too short
Description too long
H1 too short
Duplicate pages without canonical
More than one body tag on page
Title is empty
Title is missing
More than one title tag on page
Lorem Ipsum content on the live site
H1 duplicates
Description duplicates
H1 is empty
Description is empty
H1 is missing
More than one description tag on page
HTML lang attribute missing
Low word count
HTTPS page links to HTTP image
Page has not been updated more than 1 year
H2 is missing
Author box with "Admin"
Page has no list markdown
Page might have an outdated title
Paragraphs are missing
Page code has less than 500 symbols
Title too long
H1 too long
Description too short
Description = Title
H1 starts with a lowercase letter
H2 starts with a lowercase letter
Title starts with a lowercase letter
Homepage with the title tag of “Home”
Site has a favicon

duplicate content

Issues that can lead to appearing duplicate pages in Google index and drop in positions of popular pages.

Page has identical headings
Page has identical alt tags
More than one h1 on page
Title duplicates
Canonical loop
Technically duplicate URLs
Canonical points to homepage
H1 = Description
H1 = Alt
Title = Alt
H1 = Title
Canonical points to external URL
Canonical tag in HTML and HTTP header
Working protocol redirect HTTP to HTTPS
Site’s URLs redirect to preferred version of domain name.

security

Issue that can lead to hacking the site by scammers and using it for their own purposes or stealing the data of visitors to your site.

Redirect to HTTPS is not implemented in response header
Defence against cross-site scripting attacks is not implemented
Defence against click-jacking attacks is not implemented
Defence against MIME type sniffing is not implemented
HTTPS page has internal links to HTTP
HTTP URLs
HTTPS URL contains a form posting to HTTP
HTTPS page links to HTTP CSS
HTTPS page links to HTTP JavaScript
Page has HTTP link to ogp.me
Page has HTTP link to schema.org
Page has HTTP link to www.w3.org
Page requires CAPTCHA authentication method
Expire date is 2025-08-30
Site is safe
SSL certificate is valid
Web server hides its version
No cookies are sent by the website

internal

Issues related to the correct spelling of URL addresses.

4xx client errors
URL contains no Google Tag Manager code
5xx server errors
Timed out
HTTP URL contains a password input field
Has link with a URL referencing LocalHost or 127.0.0.1
Has link with a URL referencing a local or UNC file path
URL resolves under both HTTP and HTTPS
Page has broken CSS files
Page has broken images
Page has broken JavaScript files
Has a link with whitespace in href attribute
Page has empty src attributes
URL contains upper case characters
URL contains repetitive elements
URL contains non-ASCII characters
Query string contains a question mark
Long URLs
URL contains more than one Google Tag Manager code
Query string contains sort parameters
Query string contains search or filter parameters
Query string contains repetitive parameters
Query string contains paginated parameters
Whitespace in URL

page speed

Issues that can lead to slow page loading speed and a decrease in the percentage of conversions as a result.

Home page is rated 25 of 100 in Mobile PageSpeed Insights
Avoid excessive DOM width
Add dimensions to images
Defer offscreen images
Serve images in next gen formats
Page size is over 4 MB
Serve static assets with an efficient cache policy
Image size is over 100 KB
CSS file size is over 15 KB
JavaScript file size is over 25 KB
Page size is over 2 MB
Avoid excessive DOM size
Avoid excessive DOM depth
Use video formats for animated content
Comments in code has more than 1000 symbols
Home page is rated 100 of 100 in Desktop PageSpeed Insights

redirects

Issues related to redirects and redirect chains which can degrade the user experience and make it difficult to crawl pages for Googlebot.

Internal redirects from trailing slash mismatch
301 redirects
Redirect chains
Meta refresh redirect
Internal redirects from case normalization
Internal URL redirect broken
Internal URL redirects back to itself
HTTPS to HTTP redirect
HTTP to HTTPS redirect
3xx other redirects
302 redirects

social media

Issues that can lead to snippets of pages on social networks looking unattractive and, as a result, their click-through rate will drop.

Twitter card incomplete
Open Graph tags incomplete
Open Graph tags missing
Twitter card missing
Open Graph URL not matching canonical
Home page has links to social media pages

code validation

Issues that indicates that page code is not implemented in compliance with the standards and recommendations set by the World Wide Web Consortium (W3C) for the web.

Headings hierarchy is broken
Page has identical HTML id attributes
Page has tags with style attributes
<html> tag is empty
Page has no declared <!doctype html>
Google Tag Manager code in <body>
PHP fatal error
Page contains different structured data formats
Page has <table> but has no <caption> attribute
Page has <table> but has no <th> attribute

search traffic

Potential issues that exist within the search traffic data and status of pages' crawlability and indexability.

Connect Google Analytics and Search Console properties to Sitechecker
Track keywords on Sitechecker
Page has 0 impressions
Non-indexable page that has at least 1 impression
Page is blocked by robots.txt and has at least 1 impression
4xx pages that have at least 1 click
Canonicalized pages that have at least 1 click
3xx pages that have at least 1 click
Page is not submitted to sitemap and has at least 1 impression
Page has at least 1 click
Orphan pages with impressions

mobile friendly

Issues that can lead to bad user experience when they visit your website on mobile devices.

Has one or more image-map <map> tags
Missing <viewport> meta tag in <head>
Multiple viewport <meta> tags were found in <head>
Unsupported browser plugins found
Viewport <meta> tag does not have a width set
Viewport <meta> tag has a maximum-scale set
Viewport <meta> tag has a minimum-scale set
Viewport <meta> tag has a specific width set
Viewport <meta> tag is missing an initial-scale
Viewport <meta> tag initial-scale is incorrect
Viewport <meta> tag prevents the user from scaling

xml sitemaps

Issues that can lead to crawling of non-200 URLs or missing of pages with search traffic in XML sitemaps.

4xx client errors in XML sitemaps
5xx server errors in XML sitemaps
Canonicalized URL in XML sitemaps
Disallowed URL in XML sitemaps
Noindex URL in XML sitemaps
3xx redirects in XML sitemaps
Timed out URL in XML sitemaps
URL in multiple XML sitemaps
Robots.txt file contains a link to XML sitemap file

localization

Issues related to implementation of outgoing and incoming hreflang tags that help Googlebot understand language and regional targeting.

HTML lang attribute invalid
Hreflang annotation invalid
More than one page for same language in hreflang
Page referenced for more than one language in hreflang
Self-reference hreflang annotation missing
Hreflang to non-canonical
Has outgoing hreflang annotations using relative URLs
Mismatched hreflang and HTML lang declarations
Has outgoing hreflang annotations to redirecting URLs
Invalid incoming hreflang annotations
Noindex URL has incoming hreflang
Missing reciprocal hreflang (no return-tag)
Has outgoing hreflang annotations to broken URLs
Has outgoing hreflang annotations to disallowed URLs
Has outgoing hreflang annotations to noindex URLs
Canonicalized URL has incoming hreflang
Disallowed URL has incoming hreflang
Has conflicting incoming hreflang annotations
Hreflang defined but HTML lang missing
X-default hreflang annotation missing
Not all pages from hreflang group were crawled
Hreflang annotation also x-default
Missing hreflang annotations