SEO Technical Checklist
I rarely find a site that passes all seven checklist items on first pass, so start with crawlability and indexation before touching speed.
How I’d prioritise
- Start with robots.txt and accidental noindex — these block visibility entirely.
- Fix canonical tags and redirect chains before optimising speed.
- Check Core Web Vitals on your top 5 templates, not a random homepage.
- Run a mobile usability test on all major page templates.
- Use Google Search Console's Pages report to find indexation errors.
The list
This list orders checks by how likely they are to break your site if wrong. Start at the top.
Crawlability: Check your [robots.txt](/robots-txt/) for accidental blocking of important paths. Submit [XML sitemaps](/sitemap/) to Search Console and verify no included URLs return 4xx or 5xx. Scan for unintended noindex tags using a crawler or Search Console's Pages report.
Indexation: Review [canonical tags](/canonical-tag/) and [redirect chains](/301-redirect/). Use Search Console to find soft 404s or pages blocked by noindex. Fix any canonicalised incorrect versions, especially on [duplicate content](/duplicate-content/).
Performance: Run [Core Web Vitals](/core-web-vitals/) on your top 5 templates by traffic. LCP under 2.5 seconds, CLS under 0.1, FID under 100ms. For JavaScript-heavy sites, test rendered HTML versus source. Tools: PageSpeed Insights, CrUX.
Mobile usability: Use Google's Mobile-Friendly Test on each template. Fix viewport issues and tap targets. Internal linking: Check that important pages are within three clicks from homepage. Structured data: Validate with [Schema](/schema/) and the Rich Results Test for each template type.
When to stop
Stop when every blocking issue is resolved: no robots.txt blocks on valuable pages, no accidental noindex, no 5xx errors on critical URLs. Next, confirm canonical tags and redirects are logically sound. Then verify performance on top templates and mobile usability.
I used to spend weeks optimising every page for 100 Lighthouse. That is wasted. Once high-traffic templates pass Core Web Vitals and mobile test, move on. The remaining 2% of issues won't shift rankings. For most sites, 80% of traffic comes from 20% of pages — focus there. I have seen teams fix all technical issues and still not rank because their content was thin. That is the real stopping rule.
One exception: e-commerce sites with faceted navigation need pagination and canonical handling because filter parameters create thousands of near-duplicates. Add that to the checklist before stopping.
Also stop if you are neglecting content and links. Technical fixes enable discovery but do not earn relevance. Allocate no more than 20% of your SEO time to technical if you haven't done the other work.
What I got wrong
I once blocked an entire /blog/ directory in robots.txt because I thought it was low-value, but the blog was generating leads. Took weeks to notice the traffic drop. Now I never block a directory without checking its traffic first in Google Analytics. Lesson: assume nothing and verify traffic sources before excluding.
I relied on XML sitemaps to fix poor internal linking. Sitemaps help discovery but do not replace a logical site architecture. Important pages still need internal links from other pages. Google may not crawl every sitemap URL.
I audited sample URLs instead of all templates. One client had a perfect homepage LCP but their product pages, which drove 70% of revenue, were over 6 seconds. Now I always check top templates, not the URL that looks cleanest. I also once ignored soft 404s because they returned a 200 status. But Google treated them as 404s and deindexed those pages. Now I check for soft 404s using Search Console's coverage report.
I ignored hreflang tags on a multilingual site and served wrong language versions in search results. Adding them to my checklist fixed it. I also used to chase tool scores instead of real user metrics. CrUX data from Search Console is more reliable than a single run.
Next step
Quick answers
What is the single most important technical SEO check?
Checking robots.txt for accidental blocking, and scanning for unintended noindex tags. If either blocks your money pages, Google cannot crawl or index them at all. Fixing these two issues usually restores visibility quickly — I have seen recovery within 24 hours of resubmitting a sitemap. Start here because these are the most common and most impactful issues.
How often should I run a technical SEO checklist?
I run a full checklist quarterly for established sites and monthly for sites with frequent content or platform changes. Between audits, set up alerts in Search Console for manual actions, coverage drops, and Core Web Vitals regressions. That catches urgent issues without constant manual checks. Heavy-traffic templates should be monitored via CrUX weekly.
Do I need to fix every technical issue found?
No. Prioritise fixes that block crawling, indexation, or performance. A single broken internal link is less urgent than a sitewide noindex. I fix blocking issues first, then template-level problems, and skip isolated edge cases until they affect user experience or rankings. This approach stops you from wasting time on noise.
Sources
Primary documentation is linked directly. Anything commercial is marked nofollow.
- Google Search Central — Primary reference for crawling, indexing, sitemaps, and robots.txt checks in the checklist.
- Google Search Central SEO Starter Guide — Backs up the importance of crawlability and indexation as first steps.
- Google Search Console Help — Used for diagnosing index coverage, sitemap issues, and Core Web Vitals data.
- Google Search Central — Core Web Vitals — Authoritative guide for performance metrics that appear in the checklist.
Notes from Callum Bennett.