Everything SkySiteAudit checks
Crawlability & indexing
Can search engines reach, crawl and index the page correctly? Weight in score: 30%.
Page returns a successful HTTP status
Pages that return 4xx or 5xx errors cannot be indexed and frustrate visitors.
No redirect chains
Each extra redirect hop adds latency and can dilute crawling efficiency.
Page is indexable
A noindex directive (meta robots or X-Robots-Tag) tells search engines not to show the page.
Page is allowed by robots.txt
URLs disallowed in robots.txt cannot be crawled, so their content is not evaluated by search engines.
Valid canonical link
A canonical link tells search engines which URL is the preferred version of duplicate or similar pages.
Canonical targets resolve successfullysite-wide
Canonicals pointing at redirects or errors send conflicting signals.
Valid hreflang annotations
Incorrect language/region codes or missing self-references make hreflang annotations ineffective.
robots.txt is reachable and validsite-wide
Search engines read robots.txt first. A server error there can stop crawling of the whole site.
XML sitemap is present and validsite-wide
Sitemaps help search engines discover all important URLs.
Sitemap URLs return 200site-wide
Sitemaps should only list final, indexable URLs.
www and non-www versions are consolidatedsite-wide
If both www and non-www hosts serve the same content without redirecting, duplicate versions of the site exist.
No trailing-slash duplicatessite-wide
When /page and /page/ both return 200 they are duplicate URLs.
On-page SEO
Titles, descriptions, headings, content and metadata. Weight in score: 25%.
Title tag present
The title is the main headline shown in search results and browser tabs.
Title length is reasonableheuristic
Very long titles get truncated in results; very short titles waste the opportunity to describe the page. Search engines truncate by pixel width, so character counts are an approximation.
Meta description present
The meta description is often used as the snippet below your title in search results.
Meta description length is reasonableheuristic
Descriptions that are too long get truncated; very short ones rarely persuade searchers.
Exactly one H1 heading
A single clear H1 tells visitors and search engines what the page is about.
Logical heading hierarchyheuristic
Skipping levels (e.g. H2 → H4) makes the structure harder to follow for screen readers.
Sufficient text contentheuristic
Pages with very little text often struggle to rank. Word count is a rough heuristic — quality and intent matter more.
Images have alt attributes
Alt text describes images to screen-reader users and to search engines.
Social preview tags (Open Graph)
Open Graph tags control how the page looks when shared on social networks and messaging apps.
Structured data syntax
Structured data (JSON-LD) can make pages eligible for rich results. Syntax errors make it unusable. This check validates syntax and @type presence only — not eligibility for specific rich results.
Unique page titlessite-wide
Identical titles make it hard for search engines and users to tell pages apart.
Unique meta descriptionssite-wide
Duplicate descriptions reduce the usefulness of search snippets.
No duplicate page contentheuristicsite-wide
Pages whose visible text is identical compete with each other. Detected by hashing normalized body text — near-duplicates are not detected.
Links
Internal link health and anchor quality. Weight in score: 10%.
No broken internal links
Broken links waste crawl budget and send visitors to error pages.
Links have descriptive text
Links without text (or with only an image lacking alt text) give no context to users or search engines.
No orphan pagesheuristicsite-wide
Pages listed in the sitemap that no crawled page links to are hard for users and crawlers to find. Only evaluated when the crawl covered the whole site.
Performance
Server response, page weight and lab-measured loading metrics. Weight in score: 15%.
Fast server response (TTFB)
Time to first byte measured from SkySiteAudit’s server. Slow responses delay everything else. Network distance affects this value.
Reasonable HTML size
Very large HTML documents take longer to download and parse.
Text compression enabled
Gzip or Brotli typically shrinks HTML by 60–80%.
Largest Contentful Paint (lab)
LCP measures when the main content appears. This is a single lab measurement in headless Chromium with mobile emulation — not real-user (field) data.
Cumulative Layout Shift (lab)
CLS measures unexpected layout movement during load. Lab value from one page load; real-user CLS may differ.
Total Blocking Time (lab)
TBT sums long JavaScript tasks during load; it is a lab proxy for responsiveness. INP requires real-user interaction data and is reported as unavailable.
First Contentful Paint (lab)
FCP marks when the first text or image is painted. Lab measurement.
Images are reasonably sized
Large image files slow down loading, especially on mobile connections.
Mobile & accessibility
Viewport, layout on small screens and basic accessibility signals. Weight in score: 10%.
Page declares its language
The lang attribute helps screen readers pronounce content and helps search engines understand the language.
Mobile viewport configured
Without a viewport meta tag, mobile browsers render the page as a zoomed-out desktop layout.
No horizontal scrolling on mobile
Content wider than the screen forces visitors to scroll sideways. Measured in headless Chromium at 412px width.
Tap targets are large enoughheuristic
Links and buttons smaller than about 24×24 CSS px are hard to tap. Measured in headless Chromium.
Legible font sizes on mobileheuristic
Text smaller than 12px is hard to read on phones. Measured in headless Chromium.
Form fields have labels
Unlabelled inputs are not announced correctly by screen readers.
Security
HTTPS, certificate and informational security headers. Not a security certification. Weight in score: 10%.
Page is served over HTTPS
HTTPS protects visitors and browsers mark plain HTTP pages as “Not secure”.
HTTP version redirects to HTTPSsite-wide
If http:// still serves content, duplicate versions of the site exist and visitors may land on the insecure one.
Valid TLS certificate
Browsers block or warn on invalid or expired certificates.
No mixed content
HTTP resources on an HTTPS page are blocked or flagged by browsers. Detected from the HTML source only.
Recommended security headers
Headers like HSTS, X-Content-Type-Options and a frame policy reduce common browser-side risks. Informational only; not a security audit.
Tools
- Fully working
SEO Checker
Full one-page SEO audit
Limit: One page per scan for visitors; full-site crawls need a free account.
- Fully working
Website Crawler
Scan your entire website for SEO issues
Limit: Up to 50 pages per crawl for unverified sites; up to the published fair-use limit for verified sites.
- Working with limits
Page Speed Test
Page speed and Core Web Vitals (lab)
Limit: Lab data from one load in headless Chromium with mobile emulation — real users may see different values.
- Fully working
Robots.txt & Sitemap Validator
Parse and validate robots.txt and XML sitemaps
Limit: Up to 10 sitemap files and 5,000 URLs are read per check.
- Fully working
HTTP Headers & Redirect Checker
Headers, redirect chains, TLS and canonical
Limit: Security headers are informational; this is not a security audit or certification.
- Working with limits
Structured Data Validator
JSON-LD and microdata syntax check
Limit: Validates syntax and types only — not eligibility for specific Google rich results.
- Working with limits
Rank Tracking
Track rankings from your own Search Console data
Limit: SkySiteAudit does not scrape Google — live worldwide SERP tracking is not possible for free without violating search engine terms.
- Working with limits
Backlink Analysis
Check backlinks you know about
Limit: SkySiteAudit has no internet-wide backlink index; it cannot discover unknown backlinks.
- Working with limits
Keyword Research
Keywords from your pages and Search Console
Limit: No search volume or keyword difficulty numbers — those require paid datasets, so they are not shown.
- Fully working
Competitor Analysis
Compare technical SEO side by side
Limit: Public pages only — no access to competitors' rankings, traffic or Search Console data.
- Fully working
Content Optimization
Evidence-based on-page suggestions
Limit: Suggestions are rule-based; no AI rewriting.
- Fully working
Uptime Monitoring
Monitor website availability
Limit: Only for websites whose ownership you have verified.
- Fully working
PDF Reports
Download and share reports
Limit: Share links for private project reports can be revoked at any time.
Reports
Every audit can be downloaded as a PDF or as a CSV containing each individual check result with its evidence. Project reports are private; you can share them with expiring links. All reports state when the data was collected and how it was measured.