# Platform and specification checks

Two tabs in Monitor look at a site as a whole rather than page by page. **Platform** checks the property itself: whether it is up, served over HTTPS with a valid certificate, redirected consistently, and readable by search engines through robots.txt and sitemaps. **Specification** measures your pages against the Website Specification, a published standard for well-built sites. Platform findings can alert you; Specification results never do.

> **Before you start:** Monitor must be enabled for your workspace. It is set up by arrangement, so if you do not see the **Monitor** icon in the top bar, [contact us](/contact/).

## The Platform tab

The **Platform** tab shows what is **Open right now** on the property, then its current state:

| Section | Fields |
| --- | --- |
| **Domain** | **Origin**, **HTTPS**, **Pages tracked** |
| **Certificate** | **Expires**, **Days left**, **Last checked** |
| **Uptime** | **Monitoring**, **Status**, **Last probe** |
| **robots.txt** | **Present**, **Rules**, **Crawl delay**, **Last read** |
| **XML sitemaps** | **Declared**, **URLs seeded** |
| **robots.txt, in full** | The complete file as last read |

Uptime is probed every minute. Every other platform check runs every hour.

## Platform checks

| Check | Severity | What it means |
| --- | --- | --- |
| **The site is not responding** | Critical | The origin returned a 5xx or did not answer. A failure is confirmed by a second probe before it is reported. A 4xx is not treated as down |
| **The site is not served over HTTPS** | Critical | The site’s address is `http`, not `https` |
| **The TLS certificate has expired** | Critical | Visitors see a browser warning |
| **The TLS certificate expires soon** | Warning | The certificate expires within 14 days |
| **The http address serves the site instead of redirecting to https** | Critical | The `http://` address answers with the site instead of redirecting |
| **The other hostname serves the site instead of redirecting** | Warning | For example, `www.` and the bare domain both serve the site |
| **robots.txt blocks search engines from the entire site** | Critical | robots.txt disallows everything |
| **robots.txt blocks Workover from crawling this site** | Warning | robots.txt blocks the `WorkoverMonitor` user agent |
| **robots.txt changed** | Warning | The file is different from the last time Monitor read it |
| **robots.txt cannot be fetched** | Warning | Monitor could not read the file |
| **No sitemap is declared** | Warning | No sitemap in robots.txt or at the usual locations |
| **A declared sitemap cannot be fetched** | Warning | A sitemap listed for the site could not be read |
| **robots.txt does not point to a sitemap** | Info | robots.txt has no `Sitemap:` line |
| **A Sitemap line in robots.txt is not an absolute URL** | Info | A `Sitemap:` line uses a relative path |
| **robots.txt sets a crawl delay** | Info | robots.txt includes a `Crawl-delay` rule |

Every new site starts with alert rules for **The site is not responding**, **robots.txt blocks search engines from the entire site** and **The TLS certificate expires soon**. See [Alerts and incidents](/docs/alerts-and-incidents/).

## The Specification tab

The **Specification** tab shows how the site measures against [the Website Specification](https://specification.website). It gives a conformance percentage and a count of passing and failing checks, broken down by category:

- Foundations
- SEO
- Accessibility
- Security
- Well-known URIs
- Agent readiness
- Performance
- Privacy
- Resilience
- Internationalisation

Each item on a page passes, fails or does not apply. Items that do not apply to a page, for example a cookie rule on a page that sets no cookies, are excluded from the percentage.

Page-level items are evaluated from the HTML and response headers Monitor already fetched when it checked the page. Items that need a rendered browser (such as color contrast), DNS records or the HTTP version are not measured directly: most are left out, and a few are judged from a hint in the HTML or headers.

Specification results are recommendations, not incidents. Nothing on this tab opens an incident or sends an email. Each page’s detail screen also has a **Specification** section with that page’s results. See [Pages and crawl activity](/docs/pages-and-crawl-activity/).

## How this differs from the health score

The health score, out of 1,000 for each page and for the site, is driven by Monitor’s own checks. See [Issues and severity](/docs/issues-and-severity/). The Specification percentage is a separate measure against an external standard, and does not affect health or alerts.

## Related

- [Issues and severity](/docs/issues-and-severity/)
- [Alerts and incidents](/docs/alerts-and-incidents/)
- [Monitor site settings](/docs/monitor-settings/)
- [What Monitor does](/docs/monitor-overview/)