Technical SEO Checklist: What to Check and Fix First

Technical SEO is the part nobody sees and everything depends on. The best content in the world does nothing if Google cannot index the page. This checklist goes in the order I work through a site, from the problems that matter most to the ones that matter least.

Do you need a technical audit?

Probably, if any of these are true:

• Traffic dropped and you do not know why.
• The site was recently redesigned, rebuilt or moved to a new domain.
• Important pages do not appear in Google when you search for them.
• Search Console shows errors you do not understand.
• Nobody has ever checked.

1. Indexing: is Google storing your pages?

Open Google Search Console and go to the Pages report. It shows which pages are indexed and, more usefully, which are not and why.

Look for your most important pages in the "not indexed" list. Common reasons:

• Crawled, currently not indexed: Google looked and decided the page was not worth storing, often because it is thin or very similar to another page.
• Discovered, currently not indexed: Google knows the page exists but has not crawled it yet.
• Excluded by noindex tag: the page tells Google not to index it, sometimes deliberately, often left over from development.
• Blocked by robots.txt: a rule in your robots file stops Google crawling it.

A single noindex tag left on after a redesign can remove a whole site from Google. It is the first thing I check after any rebuild.

2. Sitemap and robots.txt

• Your sitemap should list every page you want indexed, and only those, and be submitted in Search Console.
• Your robots.txt should not block anything important. Visit yoursite.com/robots.txt and read it. If you see "Disallow: /", the whole site is blocked.

3. Redirects and broken pages

• Old URLs that moved should 301 redirect to their new home, not to the homepage and not to a 404.
• Links on your own site should point directly to the final URL rather than through a chain of redirects.
• Pages that no longer exist should return a proper 404, not a page that says "not found" while telling Google everything is fine.

This matters most after a redesign, when URLs often change without anyone mapping old to new. Losing those redirects is one of the fastest ways to lose rankings built over years.

4. Duplicate pages and canonicals

When the same content is available at several addresses, with and without www, with and without a trailing slash, or with tracking parameters, Google has to choose one. A canonical tag on each page tells it which version you prefer.

Check that every page has a canonical pointing at its own preferred address, and that your site redirects every variation of the domain to one version.

5. Speed and Core Web Vitals

Google measures real-world experience through Core Web Vitals: how fast the main content loads, how quickly the page responds to a tap or click, and whether the layout jumps around while loading. Search Console shows how your pages perform for real visitors.

Speed is rarely the difference between page one and page five, but a very slow site loses visitors before they read anything. The usual culprits are oversized images, too many plugins or apps, and heavy scripts.

6. Mobile

Google indexes the mobile version of your site. If content, links or structured data exist on desktop but not mobile, Google may not see them. Check every important page on a phone.

7. HTTPS and security

Every page should load over HTTPS, and the HTTP version should redirect to it. Mixed content warnings, where a secure page loads insecure images or scripts, should be fixed.

8. Structured data

Structured data helps search engines understand what a page is: an article, a product, a business, a review. It will not rescue a weak page, but it helps a good one get understood and shown more richly. Check it for errors in Search Console.

What to fix first

Not everything on this list matters equally. In order:

1. Anything stopping important pages being indexed.
2. Broken redirects, especially after a redesign.
3. Duplicate pages competing with each other.
4. Severe speed or mobile problems.
5. Everything else.

A site with ten small issues and its key pages indexed will usually outperform a technically perfect site that is missing half its pages from Google. More on each problem is in the technical SEO articles, and if you want a second pair of eyes, get in touch.

Frequently asked questions

How often should I do a technical SEO audit?

Do a full audit after any redesign, migration or significant drop in traffic, and a lighter check every few months. Search Console flags many problems as they appear, so checking it monthly catches most issues early.

Can I do a technical SEO audit myself?

You can do much of it with Google Search Console, which is free. Check the Pages report for indexing problems, the Core Web Vitals report for speed and your sitemap status. Diagnosing the causes and fixing them often needs more technical help.

What is the most common technical SEO problem?

In my experience, problems left behind by redesigns: noindex tags left on, old URLs not redirected, and duplicate versions of pages. They are easy to cause, invisible to visitors and can wipe out years of rankings.

Does site speed affect Google rankings?

Yes, but less than relevance and content quality. Speed is part of Google's page experience signals and matters most when competing pages are otherwise similar. Its bigger effect is on visitors, who leave slow pages before reading them.