What does Lemwatch monitor?

Lemwatch runs 20+ automated checks per site: uptime, response time, SSL/TLS expiry, domain expiry, DNS changes, sitemap health, broken links, content changes, SEO audits, mobile usability, security headers, and more.

Yes. The free tier monitors up to 5 sites. Pro is $19/month for 50 sites and Agency is $59/month for 100 sites, both with full feature access.

How is Lemwatch different from UptimeRobot or Pingdom?

Lemwatch bundles uptime, change detection, SEO audits, security scans, and a public API in one platform — features competitors charge separately for. It also includes team workspaces, white-labelled status pages, and a webhook system out of the box.

Does Lemwatch send alerts?

Yes. Lemwatch supports email, browser push, webhooks, and per-site notification routing so the right person hears about the right incident.

Is there a public API?

Yes. Pro and Agency plans get a public REST API with webhooks for sites, checks, incidents, and reports.

HTML Validation Checks

Validate your HTML against W3C standards and fix structural issues.

HTML Validation Checks

LemWatch validates your pages against W3C HTML standards and flags structural issues that can affect SEO, accessibility, and browser rendering.

What Gets Checked

HTML errors — Unclosed tags, missing required attributes, invalid nesting
Warnings — Deprecated elements, redundant attributes, accessibility hints
Fatal errors — Malformed markup that prevents proper parsing
Info messages — Best practice suggestions

Why HTML Validation Matters

Impact Area — How Invalid HTML Hurts —

SEO — Search engines may misinterpret your content structure —

Accessibility — Screen readers rely on valid HTML for navigation —

Browser rendering — Different browsers handle errors differently —

Performance — Invalid markup can trigger additional parser work —

Results

For each page checked, you'll see:

Error count — Issues that violate the HTML specification
Warning count — Non-critical issues and best practice suggestions
Fatal errors — Critical issues highlighted separately
Line numbers — Exact location of each issue in your source code

Common Issues

Missing alt attributes — All <img> elements need alt text
Unclosed tags — <div> without </div> causes rendering issues
Duplicate IDs — Each id attribute must be unique on a page
Missing lang attribute — <html lang="en"> helps accessibility and SEO
Deprecated elements — <center>, <font>, <marquee> should be replaced with CSS

Lemwatch — All-in-One Website MonitoringUptime, performance, SEO, security, and change detection in one platform. Free tier available.Pricing · Features · Sign Up