SEO checks reference

Every monitored crawl runs the checks below on each HTML page in your sitemap. Findings appear in run reports and deploy diffs when they are new or resolved versus your baseline. Short “Typical fix” hints in the dashboard come from CheckCatalog in SignalDiff.Shared—update the catalog and this page when adding checks.

On this page

Crawl health

Whether pages can be fetched and internal links resolve. Failures here often block other checks for that URL.

HTTP Status Error

What it detects: The page response is not HTTP 2xx (for example 404, 410, or 500).
Why it matters: Search engines and users cannot reliably access the page; other on-page checks may not run.
Typical fix: Restore the URL, fix routing or server errors, or remove it from the sitemap if it was retired intentionally.

Fetch Error

What it detects: The crawler could not retrieve the page (network error, DNS failure, timeout, or TLS problem).
Why it matters: The URL is unreachable from the crawl environment, so SEO signals cannot be evaluated.
Typical fix: Verify the host is public (or use a customer agent for internal sites), check DNS and firewall rules, and increase timeout if the page is slow.

Broken Internal Link Error

What it detects: An <a href> on the page points to another URL on the same site that returns HTTP 4xx/5xx or a non-2xx status when probed.
Why it matters: Broken internal links waste crawl budget, hurt user experience, and can dilute link equity.
Typical fix: Update or remove the link, fix the target page, or redirect the old URL to the correct destination.

Orphan Page Warning

What it detects: A crawled HTML page has no incoming internal links from any other page on the site (the homepage is excluded).
Why it matters: Pages with no incoming internal links are hard for users to discover and may rely on the sitemap or external links for crawling.
Typical fix: Add internal links from navigation, hub pages, or related content so visitors and crawlers can reach this URL without relying on the sitemap alone.

Indexability

Signals that control whether search engines should index a URL and which URL is canonical.

NoIndex Warning

What it detects: noindex in <meta name="robots"> or in the X-Robots-Tag response header.
Why it matters: The page asks search engines not to include it in results—often intentional for staging or utility pages, but harmful on pages you want indexed.
Typical fix: Remove noindex from production pages that should rank, or keep it and exclude those URLs from the sitemap.

Canonical Warning Info

What it detects: Missing <link rel="canonical">, an empty href, or a canonical URL that differs from the crawled URL. Warning for missing or empty; Info when canonical points elsewhere.
Why it matters: Canonical tags consolidate duplicate or parameterized URLs so search engines know the preferred version.
Typical fix: Add a self-referencing canonical on indexable pages, or point duplicates at the primary URL. Confirm cross-domain canonicals are intentional.

Sitemap Warning

What it detects: A URL appears in your sitemap but is also marked noindex (meta or header).
Why it matters: You are telling crawlers to discover a URL in the sitemap while simultaneously asking them not to index it—a conflicting signal.
Typical fix: Remove the URL from the sitemap, or remove noindex if the page should be indexed.

On-page SEO

Core HTML elements that influence rankings, snippets, and content quality.

Title Error Warning

What it detects: Missing or empty <title> (Error), or title text shorter than 10 characters or longer than 60 characters (Warning).
Why it matters: The title is the primary label in search results and browser tabs; missing or poor titles reduce click-through and clarity.
Typical fix: Add a unique, descriptive title per page. Aim for roughly 10–60 characters with the main topic and brand where appropriate.

Meta Description Error Warning

What it detects: Missing or empty <meta name="description"> (Error), or description shorter than 50 or longer than 160 characters (Warning).
Why it matters: Meta descriptions often appear as snippet text in search results and help users decide whether to click.
Typical fix: Write a concise summary (about 50–160 characters) that matches page intent and includes a clear value proposition.

Heading H1 Error Warning

What it detects: No <h1> on the page (Error) or more than one <h1> (Warning).
Why it matters: A single clear H1 helps users and search engines understand the main topic of the page.
Typical fix: Use one H1 that reflects the page topic; demote extra top-level headings to H2 or lower.

Heading Hierarchy Warning

What it detects: A heading level is used without a preceding parent level (for example <h3> before any <h2>).
Why it matters: Logical heading order improves accessibility and makes content structure easier to parse.
Typical fix: Nest headings sequentially (H1 → H2 → H3) without skipping levels in the document outline.

Missing Alt Text Warning

What it detects: <img> elements without an alt attribute, or with empty or whitespace-only alt. Purely decorative images with aria-hidden="true" or role="presentation" are skipped.
Why it matters: Alt text helps search engines understand image content and is shown when images cannot be displayed.
Typical fix: Add concise, descriptive alt text to each content image. Use alt="" with aria-hidden="true" only for purely decorative images.

Low Word Count Warning

What it detects: Visible body text below 50 words (navigation, boilerplate, and hidden content are excluded).
Why it matters: Very thin pages may struggle to rank for competitive queries and can look incomplete to users.
Typical fix: Add substantive copy, merge thin URLs into stronger pages, or use noindex if the page is intentionally minimal.

Duplicate Title Warning

What it detects: The same <title> text appears on more than one crawled page in the run.
Why it matters: Duplicate titles make it harder for search engines to distinguish pages and can reduce snippet relevance.
Typical fix: Give each indexable URL a unique title that reflects its specific content or intent.

Duplicate Description Warning

What it detects: The same meta description appears on more than one crawled page in the run.
Why it matters: Repeated descriptions provide little differentiation in search snippets across similar URLs.
Typical fix: Write unique descriptions per page, or canonicalize duplicate URLs if they should not exist separately.

Informational

Context about redirects and duplicate URLs—not always problems, but worth reviewing.

Off-Domain Redirect Info

What it detects: The sitemap URL redirects to a different registrable domain than the site being crawled.
Why it matters: May indicate outdated sitemap entries, cross-domain moves, or tracking redirects that should not be in the sitemap.
Typical fix: Update the sitemap to list final indexable URLs on the correct host, or remove URLs that intentionally leave the site.

Duplicate Path Info

What it detects: Two sitemap URLs resolve to the same normalized page content (for example trailing-slash or alias URLs).
Why it matters: Duplicate URLs can split signals unless canonicalized or redirected to one preferred version.
Typical fix: Pick a canonical URL, add 301 redirects or canonical tags, and trim redundant entries from the sitemap.