SEO Site Checker: Fix What It Finds

An SEO site checker scans your website the way a search engine would and hands you a list of everything that could be holding rankings back: broken links, slow pages, missing tags, thin content, and more. The scan is the easy part. This guide explains what a site checker actually looks at, how to read its report without panicking, and exactly how to fix the issues it flags, using free tools you can start with today.

What an SEO site checker actually does

A site checker is a crawler plus a rules engine. It starts at a URL you give it, follows the links it finds, and fetches each page the way a search bot would. As it goes, it records the response code, the load behavior, the HTML tags, and the internal link structure, then compares all of that against a checklist of known SEO best practices. The output is a prioritized report: red items that are actively hurting you, amber items worth improving, and green items that already pass.

It is important to be honest about what these tools are. A checker is a diagnostic instrument, like a blood-pressure cuff. It tells you the reading; it does not change the reading. Every fix still happens in your CMS, your templates, or your server config. Any product that promises to "automatically fix your SEO" with one click should be treated with suspicion, because most meaningful fixes require a human decision about content and structure. If you want the wider context around scanning tools generally, our SEO checker guide covers the same territory from a different angle.

The categories a good checker reports

Most reports group findings into a few buckets. Knowing the buckets helps you read any tool, because the labels differ but the underlying checks rarely do.

• Crawlability and indexing: Can bots reach your pages? Are important URLs blocked by robots.txt, marked noindex, or returning error codes?
• Broken links and status codes: Internal links pointing to 404 pages, redirect chains, and mixed http and https resources.
• On-page tags: Missing or duplicate title tags, meta descriptions, H1s, and alt text.
• Performance: Page speed and Core Web Vitals, which affect both experience and ranking.
• Content quality signals: Thin pages, duplicate content, and orphaned pages with no internal links.

Real free tools you can start with

You can assemble a complete site-checking workflow without paying anything. Each of these is a real, established product, and together they cover more than most single paid scanners.

1. Google Search Console. The most important one, because it reports how Google itself sees your site: which pages are indexed, which are excluded and why, and which queries you rank for. Set it up first. Our Search Console guide walks through every report.
2. Google PageSpeed Insights and Lighthouse. Free performance analysis using both lab and real-world field data, mapped directly to Core Web Vitals.
3. Screaming Frog SEO Spider (free tier). A desktop crawler that finds broken links, redirect chains, duplicate titles, and missing tags. The free tier crawls up to 500 URLs, which is plenty for a small site.
4. Bing Webmaster Tools. Bing's free equivalent of Search Console, with its own site scan and keyword data. Coverage outside Google matters more than people assume.

How to fix crawl and indexing problems

Indexing blockers are the highest-priority findings because a page that cannot be crawled or indexed cannot rank at all, no matter how good it is. Start here. Open the indexing report and look for pages you want ranked that are marked excluded.

Common causes and fixes: a stray noindex tag left over from a staging site (remove it); a Disallow rule in robots.txt that is too broad (narrow it); or a canonical tag pointing every page at the homepage (correct the canonical to be self-referential on unique pages). If Google reports "Discovered, currently not indexed," the page usually needs stronger internal links and more depth rather than a technical fix. When the checker flags large numbers of error pages, work through our guide to 404 Not Found errors and how to fix them so you resolve the underlying links, not just the symptoms.

How to fix broken links and bad redirects

Broken internal links waste crawl effort and frustrate visitors. According to MDN's reference on the 404 status code, a 404 means the server cannot find the requested resource, and links leading to such pages are called broken or dead links. Google confirms in its documentation on HTTP status codes that URLs returning a 4xx code are not indexed, and already-indexed URLs returning 4xx are removed from the index.

To fix them: for a page that moved, add a 301 redirect from the old URL to the new one, which passes ranking signals along. For a page that is genuinely gone with no replacement, either restore the content or let it return a clean 404 or 410 and update the internal links that point to it. Avoid long redirect chains, where URL A redirects to B redirects to C; collapse them so each old URL points directly to the final destination. Our broken links guide covers the full cleanup process.

How to fix performance and Core Web Vitals

Performance findings map to the three Core Web Vitals. Per web.dev, the good thresholds are Largest Contentful Paint (LCP) within 2.5 seconds, Interaction to Next Paint (INP) of 200 milliseconds or less, and Cumulative Layout Shift (CLS) of 0.1 or less, measured at the 75th percentile of page loads.

• Slow LCP: compress and correctly size your hero image, serve modern formats like WebP, and remove render-blocking scripts.
• High INP: reduce heavy JavaScript that ties up the main thread when users interact.
• High CLS: set explicit width and height on images and reserve space for ads and embeds so nothing jumps.

Our Core Web Vitals technical guide breaks each metric down with specific fixes.

On-page tags and content depth

Once the technical foundation is clean, work the on-page findings. Give every important page a unique, descriptive title tag and meta description; duplicates confuse both users and search engines. Ensure a single clear H1 per page and a logical heading hierarchy. Add descriptive alt text to meaningful images. For thin pages, the fix is rarely a tag: it is more useful content, better internal links pointing in, and a clearer match to what searchers actually want. When you are ready to go deeper on the full audit workflow, our SEO audit guide and website SEO checker guide extend this process, and a strong backlink profile from our guide to finding backlinks for free supports everything above.

Frequently asked questions

Is there a genuinely free SEO site checker?

Yes. Google Search Console, Google PageSpeed Insights, the Screaming Frog free tier, and Bing Webmaster Tools are all free and together cover indexing, broken links, performance, and on-page tags. Many commercial tools also offer a free limited scan, which is fine for a first look.

Can a site checker fix my SEO automatically?

No. A checker diagnoses problems; the fixes happen in your CMS, templates, or server settings and usually require a human decision. Treat any "one-click fix all SEO" claim with caution, because meaningful improvements involve content and structure choices a tool cannot make for you.

How often should I run a scan?

Run a full crawl monthly for a stable site, and after any large change such as a redesign, migration, or bulk content update. Check Search Console weekly, since it updates continuously and flags urgent issues like manual actions or indexing drops.

Which issues should I fix first?

Fix indexing blockers first, because unindexed pages cannot rank at all. Then resolve broken internal links and bad redirects, then Core Web Vitals, then on-page tags and content depth. Working in that order gives you the biggest gains per hour.

Do the number scores from site checkers matter?

The overall "SEO score" out of 100 that many tools display is a rough marketing summary, not a ranking. Ignore the headline number and act on the specific findings underneath it, since those are what actually affect performance.