Search engines reward sites that are fast, crawlable and trustworthy. The trouble is that “SEO” spans dozens of small signals, and any one of them can slip without you noticing — a broken canonical here, a bloated image there. This checklist is the exact set of checks we run automatically on every crawl, grouped so you can work through them in an afternoon.
If you only fix three things this quarter, make them speed, canonicals and broken links. They move the needle the most.
Performance & Core Web Vitals
Google uses real-user performance data as a ranking signal. Three metrics matter most, and each has a clear “good” threshold:
- Largest Contentful Paint (LCP) — under 2.5s — how quickly your main content appears.
- Interaction to Next Paint (INP) — under 200ms — how responsive the page feels.
- Cumulative Layout Shift (CLS) — under 0.1 — how stable the layout is as it loads.
Most sites fail LCP first, usually because of oversized hero images or slow server response. Serving next-gen image formats and enabling text compression are the fastest wins.
Technical foundation
These are the plumbing checks — invisible to visitors, critical to crawlers. When they break, rankings can drop overnight with no obvious cause on the page itself.
- Canonical tags — present and pointing to the right URL, to avoid duplicate-content dilution.
- Robots.txt — valid and not accidentally blocking important sections.
- XML sitemap — synced, with every important page included.
- HTTPS & SSL — valid, with a healthy expiry runway and auto-renewal on.
- HTTP status codes — clean — no unexpected 404s or 5xx errors on live URLs.
Don’t forget hreflang
If you serve multiple languages or regions, mismatched or missing hreflang tags confuse search engines about which version to show. It’s a common, silent source of lost international traffic.
Content & on-page
Once the foundation is solid, on-page signals help each page earn and keep its ranking:
- Unique meta titles & descriptions — within length limits — your free ad copy in search results.
- Logical heading hierarchy — (one H1, no skipped levels) for structure and accessibility.
- Alt text on images — for accessibility and image-search visibility.
- Internal links — that spread authority to your most important pages.
Monitoring is the real secret
Running this checklist once is useful. Running it continuously is what actually protects your rankings. Sites change constantly — a new deploy, a CMS update, a third-party script — and any of these can reintroduce an issue you already fixed. The teams that win treat SEO health like uptime: monitored around the clock, with alerts the moment something breaks.
That’s exactly why we built UpCrawler — to run all 20 of these checks automatically, every few hours, and tell you the instant something needs attention.
Share it with whoever runs your site’s SEO.
