Technical SEO checklist: what to check on your site.

What technical SEO is

SEO work rests on three fronts. Content answers what people search for. Authority comes from mentions and links from other sites. And the technical side makes sure the search engine can access and understand all of it.

A comparison helps: content is what the store sells, authority is its reputation in town, and technical SEO is the door being open and the shelves being labeled. With the door closed, the rest does not matter.

Technical problems are treacherous because they do not show to people visiting the site. The page opens normally in the browser and can still be invisible to Google. That is why the check needs to be done on purpose.

How to use this checklist

You do not need paid tools for most of the list. Three free resources cover almost everything:

• Search Console. Shows which pages are indexed, which have errors and how the site performs on mobile and in speed.
• URL Inspection. Inside Search Console, it shows how Google sees a specific page.
• Rich Results Test. Checks whether the structured data is correct.

Write down what you find in a simple spreadsheet, with four columns: the page, the problem, the priority and who will fix it. Without that record, the audit becomes a list of impressions nobody acts on.

Follow the blocks in order. The first ones deal with problems that keep the page from showing up. The last ones improve how it shows up. There is no point polishing the title of a page Google cannot even read.

1. Crawling and indexing

Crawling is Google visiting the page. Indexing is storing it to show in searches. Without both, there is no ranking.

1. The robots.txt file does not block what matters. One wrong line can hide the entire site. It is the most common mistake after a site change.
2. A sitemap exists and has been submitted. The list of pages, registered in Search Console and updated automatically.
3. No important page is marked as noindex. The tag is useful on test pages, and disastrous when forgotten on a live site.
4. Each page points to its own official version. The canonical tag keeps Google from treating similar URLs as duplicate content.
5. The Pages report in Search Console has been read. It lists what was left out of the index and why.
6. There are no orphan pages. A page that gets no link from any other is unlikely to be found.

Quick test: search Google for your domain preceded by "site:". The number of results gives an idea of what is indexed. If it is much smaller or much larger than the real number of pages, there is something to investigate.

2. Site structure and URLs

1. The URLs are readable. Words separated by hyphens, no codes, describing the content of the page.
2. The site answers at a single address. With and without "www", with and without the padlock: every variation redirects to a single version.
3. Every important page is a few clicks from the home page. The deeper it is, the less Google visits.
4. The pages link to one another. Internal links with descriptive text, not "click here".
5. There is a breadcrumb trail. It helps the visitor and shows the hierarchy to the search engine.
6. Old URLs redirect. A removed or renamed page leads to the new address with a permanent redirect.
7. The error page helps. When the address does not exist, the site says so and offers a way back.

The second item deserves attention. It is common to find the same site answering at two or three versions of the address, each competing with the others for position. In Search Console, this shows up as the same page listed more than once.

3. Speed and experience

Google evaluates the loading experience through three measures, grouped under the name Core Web Vitals:

What to check:

1. Images are the right size. At the dimensions they are displayed and in a current format.
2. Images below the first screen load later. Only when the visitor gets close to them.
3. There are few third-party scripts. Every tool installed charges its toll in speed.
4. Fonts do not block the text. The content appears even before the brand font loads.
5. Nothing shifts while loading. Images and blocks with reserved space.

The Core Web Vitals report in Search Console shows how pages perform with real visitors, separating mobile and desktop. It is more reliable than a one-off test.

4. Mobile

Google uses the mobile version as the basis for indexing and ranking. If something exists only on desktop, for the search engine it is as if it did not exist.

1. The mobile content is the same as the desktop content. Copy, links and images, with no shortened versions.
2. The text is readable without zooming. And the buttons have size and space for a finger.
3. Nothing covers the screen on arrival. Windows that take over the whole page hurt the experience and can hurt ranking.
4. The menu works. Every important page can be reached on a phone.

Check on your own phone, on mobile data. That is how most of your customers will get to know the company.

5. The basics of every page

1. A unique title. Each page with its own title, describing the content, with the main search term at the start.
2. A unique description. A summary that gives a reason to click. It does not improve ranking, but it improves clicks.
3. One H1 per page. The main heading, visible, different from those on other pages.
4. Subheadings in order. H2 for sections, H3 inside them, without skipping levels.
5. Images with alt text. A short description of what the image shows.
6. The text is in the page’s code. Content that only appears after a script runs may not be read.

The last item has grown in importance. Sites assembled entirely in the browser can look complete to the visitor and nearly empty to the search engine. The way to check is URL Inspection: it shows what Google actually received.

6. Structured data

Structured data is a layer of information that tells the search engine, without ambiguity, what each thing on the page is: a company, an article, a product, a question with an answer.

Markup does not guarantee a visual highlight in the results. Google decides when to show it. Even so, it helps search engines and AI tools understand and cite the content correctly.

For companies that serve an area, local business markup works together with the Google listing. See Local SEO and how to optimize your Business Profile.

7. Security

1. The whole site uses a secure connection. The padlock appears on every page.
2. There is no mixed content. A secure page that loads an image or script over an insecure connection triggers a browser warning.
3. The system and its plugins are up to date. A hacked site can be flagged as dangerous and disappear from search.
4. There is a backup. Automatic, stored off the server and tested.

Search Console has a specific report for security issues. It is worth turning on email alerts, to know the same day if something is detected.

8. Languages and regions

It only applies to sites with more than one language, but when it applies, it is critical.

1. Each language has its own URLs. One page for Portuguese, another for English.
2. The versions point to one another. Language markup tells Google which page to show in each country.
3. The content is really translated. Unreviewed machine translation usually performs poorly.
4. The visitor can switch languages. Without being forcibly redirected by location.

When changing sites: the migration checklist

The moment of greatest risk for SEO is a site change. A redesign, a change of platform or of domain can wipe out in a day positions built over years. What cannot be missing:

1. A list of all current URLs. With the ones that get the most visits and links marked.
2. A redirect map. Each old URL pointing to its new equivalent.
3. Titles, descriptions and copy preserved. On the pages that already rank.
4. Testing before publishing. In a closed environment, blocked from Google.
5. Unblocking at publication. The test environment’s block cannot go along to the live site.
6. A new sitemap submitted. On the day of the change.
7. Daily monitoring in the first weeks. Errors, indexed pages and rankings.

Some fluctuation after the change is normal. A drop that does not recover within a few weeks almost always comes from a forgotten redirect or a block that was left in place.

What to fix first

Audit tools usually list hundreds of warnings with the same weight. The table helps you avoid spending a week on details while a block keeps the site from showing up.

Frequently asked questions

Conclusion

Technical SEO is not the most visible part of the work, and it is the one that holds up all the others. With open crawling, organized URLs, fast pages and well-marked information, the content has a chance to show up.

Use the checklist every six months and always before a site change. If you want this review done by someone who does it every month, get to know Martin’s SEO consulting.