URL
Indexability
Check that a page responds as expected and remains eligible for indexing.
Sentinel / technical SEO and content
Protect what search engines and people actually see.
A page can load perfectly while its robots directive, canonical, title, schema, analytics, or content has changed. Sentinel makes those promises explicit and keeps the before-and-after context.
CONCEPTUAL OBSERVATIONEXPECTED / OBSERVED
HTTP response200 OK200 OK
Indexabilityindex, follownoindex
Canonical/pricing/home
Analytics tagpresentmissing
Illustrative example, not a product screenshot. Actual observations depend on the target and configuration.
Beyond a basic uptime answer
Ask whether the promise still holds.
A response is the beginning of the diagnosis.
Basic uptime answersSentinel also answers
Did the server respond?Is the page still indexable and canonicalised correctly?
Is HTML returned?Did critical content, tags, schema, or dependencies change?
Is a sitemap reachable?Did URLs, media entries, or language relationships change?
Can a bot reach the site?Which configured user agent can reach it, and what changed?
Indexability and crawl policy
Catch the page that stays online but leaves the index.
Check response status, robots behaviour, indexability, canonical output, and configured hreflang pairs. A passing HTTP response is not evidence that the page still makes the intended search-facing promise.
SITE
Robots.txt change
Notice when robots.txt content or directives change.
URL
Per-URL robots fetchability
Check whether a configured user agent can fetch a monitored URL under robots.txt.
URL
Canonical URL
Check that a page points at the expected or self-referencing canonical.
URL
Hreflang map
Check configured language and region pairs on a page.
Sitemaps and URL lifecycle
Keep the URL inventory explainable.
Watch sitemap validity, additions and removals, media entries, and configured hreflang reciprocity. The appliance also retains URL lifecycle observations such as first/last seen, moved target, and last status where those records are available.
SITE
Sitemap sync
Keep a baseline of sitemap reachability and URL inventory.
SITE
Sitemap validity
Catch malformed or unreachable sitemap XML.
SITEConditional
Sitemap hreflang reciprocity
Check that sitemap language references are reciprocal and complete.
SITE
Sitemap changes
Alert when any sitemap URL delta crosses your configured rule.
SITE
Sitemap URLs added
Focus change detection on newly added sitemap URLs.
SITE
Sitemap URLs removed
Spot URLs disappearing from a sitemap.
SITEConditional
Image sitemap
Check configured image-sitemap entries and their fetchability.
SITEConditional
Video sitemap
Check configured video-sitemap entries and referenced URLs.
Content and page structure
Turn the important page promise into an assertion.
Check expected titles and H1s, required or forbidden content, selected elements, XPath counts, stale dates, and meaningful content-change baselines. CSS/XPath and regex rules are operator-configured assertions, not a claim that Sentinel rewrites the page.
URL
Title match
Catch a page title changing from its expected value.
URL
H1 match
Keep the primary page heading aligned with the intended content.
URL
Content allow/deny
Check that required text remains present and forbidden text stays absent.
URL
Element assertion
Check for a configured element and optional expected text.
URL
XPath count
Assert that a structural XPath expression has the expected count.
URL
Stale dates
Find configured copyright, publish, or structured-data dates that have aged.
URL
Content change baseline
Notice meaningful text or content-hash changes between observations.
Metadata and presentation
Watch how the page describes itself elsewhere.
Observe metadata, Open Graph, Twitter/X Cards, and Schema.org structured data so a deploy does not silently change the page’s search or social context.
URL
Metadata fields
Observe title, description, and selected social metadata fields.
URL
Open Graph tags
Check the social preview fields that a page exposes.
URL
Twitter/X Card tags
Check configured Twitter/X card fields and changes.
URL
Schema.org structured data
Observe configured JSON-LD or Microdata structured-data blocks.
Tracking and dependencies
Notice the tags and resources that support the page.
Check analytics and GTM presence, new third-party script hosts, mixed-content references, and selected HTTP security headers. These checks observe the page; they do not promise attribution, ranking, or security repair.
URL
Analytics tag
Notice when an expected analytics identifier is removed.
URL
GTM container
Notice when an expected Tag Manager container is removed.
URL
Third-party script hosts
Notice a new active-content host appearing on a monitored page.
URL
Mixed content
Notice insecure resources referenced by an HTTPS page.
URL
HTTP security headers
Observe selected response-security headers and field-level changes.
Bot accessibility
Measure configured reachability, not guaranteed inclusion.
Probe configured AI, search-engine, and SEO crawler user agents and report observed reachability changes. An access check is not a promise of crawling, indexing, ranking, or AI inclusion.
SITEConditional
Bot accessibility
Observe reachability for configured AI, search, and SEO crawler user agents.
Rendered pages
Use the optional JavaScript lane when the page needs it.
Pro can use a separate JavaScript worker for rendered checks. Core Web Vitals are provider-backed and Pro-gated; both capabilities require the relevant configuration and consume more resources than text-only checks.
URLPro
Core Web Vitals provider
Check configured performance thresholds through an external provider.
URL
Element assertion
Check for a configured element and optional expected text.
Read the qualifier
Technical SEO is observable, not guaranteed.
Sentinel checks configured conditions; it does not guarantee rankings, indexing, traffic, or inclusion in any search or AI system.
Image/video sitemap checks, bot reachability, and Core Web Vitals depend on the target, configuration, worker path, or external provider where noted.
Pro custom assertions and JavaScript rendering are operator-enabled features; the optional JS worker needs materially more resources.
Examples show expected versus observed values conceptually. They are not literal customer data or product screenshots.
Continue the build
Bring page checks into the operating workflow.
Canonical Sentinel brochure pages.