Key takeaways
- A technical audit answers a single question: can Google crawl, understand and index your site? Everything else in SEO rests on that foundation.
- Start with the Pages report in Google Search Console. The "Crawled, not indexed" and "Discovered, not indexed" statuses are the two most expensive and most frequent problems.
- The thresholds to remember: LCP under 2.5 seconds, INP under 200 milliseconds, CLS under 0.1, and never more than 3 clicks between the homepage and any important page.
- A redirect chain loses signal at every hop. Beyond two chained 301s, fix it by linking straight to the final destination.
- 20% of technical problems cause 80% of the damage. Prioritize indexing and crawl before polishing alt attributes.
Technical SEO has a reputation as a black box reserved for developers. In practice, a technical SEO audit comes down to checking a finite list of items, in a logical order, against known thresholds. You do not need to write code to work through the checklist; you need to know where to look and what to conclude. This guide gives you the 8 blocks of the technical SEO audit checklist, in the order where problems cost the most, as the detailed technical companion to our complete SEO audit guide. Spoiler: block 1 alone surfaces more problems than the other seven combined.
Block 1: indexing, the final arbiter
A page that is not indexed does not exist for Google, no matter how good its content is. So this is the first check, and the most profitable one.
Open Google Search Console and go to the Pages report. Compare the number of indexed pages with the number of pages you have actually published. Then dig into the exclusion reasons and look for these three classic Google indexing issues:
- "Crawled, currently not indexed": Google saw the page and judged it not interesting enough. Typical cause: thin content, or a page isolated within the internal linking structure.
- "Discovered, currently not indexed": Google knows the URL but never even came to look at it. Typical cause: limited crawl budget or internal linking that is too weak.
- "Page with redirect" and "Excluded by noindex tag" in abnormal quantities: often the leftovers of a migration, or a configuration mistake quietly deindexing important pages without anyone having decided it.
For each important excluded page, use the URL inspection tool in Search Console to understand the exact reason. If your entire site has gone missing from the index, the problem lies elsewhere, and our diagnostic on why your site is not showing on Google exists for exactly that.
Block 2: crawlability
Google must be able to move through your site freely and without waste. This part of the website crawl audit has four checkpoints.
The robots.txt file. Verify it does not block important sections. A Disallow: / forgotten after a production release happens more often than anyone admits. Also check that it references your sitemap.
The XML sitemap. It must exist, be submitted in Search Console, and contain only canonical URLs returning 200. A sitemap that lists redirects or noindexed pages sends contradictory signals.
Click depth. Every important page must be reachable in 3 clicks or fewer from the homepage. Beyond that, Google treats it as secondary and crawls it less often. The remedy is internal linking: categories, related articles, contextual links.
Orphan pages. A page with zero internal links pointing to it can only be found through the sitemap. Google crawls it rarely and indexes it even more rarely. Your crawler should cross-reference the list of crawled pages against the sitemap to catch them.
Block 3: redirects and status codes
Every URL on your site should respond with either a 200 (all good) or a 301 to a single, final destination. Everything else is a problem, to varying degrees.
| Status | Verdict | Action |
|---|---|---|
| 200 | Normal | Nothing |
| 301 | Normal if intentional | Check that internal links point to the final destination |
| 302 | Suspicious if permanent | Replace with a 301 if the redirect is definitive |
| 301 chain | Signal loss | Redirect directly to the final destination |
| 404 | Acceptable if deliberate | Redirect only if an equivalent page exists |
| Soft 404 | Problem | Return a real 404 or flesh out the page |
| 5xx | Urgent | Server error: fix immediately |
The most common case after a few years of a site's life: chains going A to B to C, inherited from successive redesigns. Every hop dilutes the signal and slows the crawl. The fix is mechanical: update all internal links to point straight to C, and collapse the chain into a direct A to C redirect.
Block 4: canonicals and duplicate content
Google hates having to choose between several versions of the same page. Your SEO technical audit must verify that each piece of content lives at exactly one canonical URL.
The classic sources of duplication: www and non-www both responding, http and https accessible in parallel, URLs with and without a trailing slash, tracking parameters, and on online stores, filters and variants generating infinite URLs. The quick check: take a page, test its URL variants, and confirm they all redirect to the canonical version or declare the correct rel=canonical.
Block 5: speed and Core Web Vitals
The three metrics that matter, with Google's "good" thresholds:
- LCP (Largest Contentful Paint), under 2.5 seconds: how long the main element takes to display. Usual suspects: unoptimized images, a slow server, blocking scripts.
- INP (Interaction to Next Paint), under 200 milliseconds: responsiveness to clicks. Usual suspect: too much JavaScript.
- CLS (Cumulative Layout Shift), under 0.1: visual stability. Usual suspects: images without dimensions, banners pushing content around.
Test on mobile first; that is where Google measures. And test your page templates (homepage, article, product), not just the homepage: the product or article template is often what drags the average down. The full optimization playbook is in our article on the SEO performance score.
Block 6: mobile and rendering
Google indexes the mobile version of your site, not the desktop version. Two checks.
The actual mobile display. Not just "it fits on the screen": is the text readable without zooming, are the buttons tappable without a magnifying glass, is the main content visible without scrolling through three pop-ups?
JavaScript rendering. If your site loads its content through JavaScript, check what Google actually sees via URL inspection in Search Console ("Test live URL" button, then the screenshot). Content invisible at render time is content that does not exist.
Block 7: structured data
Structured data (schema.org) helps Google understand your pages and unlocks rich results: review stars, expanded FAQs, breadcrumbs. Since the rise of AI answer engines, it also acts as the machine-readable ID card of your content.
The audit verifies three things: are the schemas present valid (test with Google's rich results tool), are the types relevant to your business in use (Article for a blog, Product for a store, FAQPage where there is a FAQ), and does the declared information match the visible content. A schema that lies (invented reviews, fake prices) exposes you to a manual action.
Block 8: the foundations
The quick tour of the basics that must be in order: HTTPS everywhere with an automatic redirect from http, a valid certificate, no mixed content. If your site is multilingual, each page must declare its language versions with hreflang, with reciprocal tags. Hreflang errors are sneaky: nothing breaks visually, but Google can serve the wrong language to the wrong country and dilute your signals across versions.
Prioritizing: not everything is equal
The checklist is long; your time is not. The prioritization rule, in order: first everything that prevents indexing (blocks 1 and 2), then everything that dilutes signals (blocks 3 and 4), then everything that degrades experience (blocks 5 and 6), and finally everything that improves comprehension (blocks 7 and 8).
Concretely: one strategic page left out of the index is worth a hundred missing meta descriptions. Do not let the long lists of small issues that tools produce hypnotize you; fix what matters first. That is exactly the logic behind Bloomwise's technical score: every detected problem is weighted by its severity and by the importance of the affected page, so the first line of your list is always the most profitable fix. We explain the weighting in the article on the technical SEO score.
The bottom line
There is nothing magical about a technical SEO audit: 8 blocks, known thresholds, a priority order. Indexing first, because a page absent from the index can win nothing. Crawl and redirects next, because diluted signals are lost rankings. Speed, mobile and structured data last, because they break the tie between equivalent content. Do it by hand with Search Console and a crawler if you have the time, or let a platform like Bloomwise run the checklist in a few minutes and hand you the fixes in order of profitability. And once the technical layer is healthy, the next lever is editorial: our method for writing SEO-optimized articles takes over from there.
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