How to Do a Technical SEO Audit in 2025: A Step-by-Step Checklist

Picture this: you've spent months building out content, earning a few solid backlinks, and your site still isn't moving. Rankings flat. Traffic stuck. You run through the usual suspects and come up empty. Here's what most people miss — the problem might not be your content at all. It might be your technical foundation. A technical SEO audit is how you find out. It checks whether search engines can actually find, read, and understand your site. Not your copy. Not your links. The structure underneath everything else.

Fair warning: fixing technical issues won't magically rank a bad site. But a solid site with hidden technical problems will consistently underperform. Think of this audit as removing the ceiling on your rankings, not building them from scratch. Work through these categories in order — some issues cascade into others.

1. Crawlability

Before anything else, can search engines actually get in? This sounds obvious, but you'd be surprised how often the answer is no — especially after a site migration or platform switch.

Check your robots.txt file

Go to yourdomain.com/robots.txt and read it carefully. A misconfigured robots.txt can accidentally block entire sections of your site from being crawled. And yes, this happens more than most agencies admit — one wrong line after a migration and your top service pages disappear from Google's view.

Review your XML sitemap

Every site needs an XML sitemap submitted in Google Search Console. Verify that it includes all your important URLs, excludes pages tagged noindex, and returns a 200 status code when accessed directly. If it's returning a 404, Google may not be getting the full picture.

Look for crawl errors and redirect chains

In Google Search Console, head to Indexing and scan for pages throwing errors. A 404 on an important page needs a fix. Redirect chains are sneakier — URL A goes to URL B, which goes to URL C. Each hop bleeds authority. Every redirect should go straight to the final destination in a single step.

2. Indexation

Crawlability means search engines can visit your pages. Indexation means they've actually added those pages to their index. You need both. Getting crawled but not indexed is like showing up to the game and sitting in the parking lot.

Use the site: search operator

Type site:yourdomain.com into Google. The result count gives you a rough estimate of indexed pages. If that number is way lower than your actual page count, something's blocking indexation. That's a problem worth digging into immediately.

Hunt down accidental noindex tags

In your page source, look for the noindex meta tag. It should only appear on pages you deliberately want hidden — like thank-you pages or admin sections. Finding it on a product or service page? That's your culprit.

Audit your canonical tags

Canonical tags tell search engines which version of a page is the real one. A misconfigured canonical can quietly push your best pages out of the index in favor of a duplicate. Check that canonicals point where you actually want them to point.

3. Page Speed and Core Web Vitals

Slow pages lose visitors before they even see your content. Google also uses page speed as a ranking factor. So the cost of ignoring this is double — you lose rankings and you lose people.

Run a PageSpeed Insights test

Go to PageSpeed Insights and test your most important pages. Focus on the three Core Web Vitals scores. Each one measures something different about how your page feels to a real user.

• LCP (Largest Contentful Paint): How fast the main content loads. Aim for under 2.5 seconds. Common fixes include optimizing images and improving server response time.
• INP (Interaction to Next Paint): How responsive your page is to clicks and taps. High scores usually point to heavy JavaScript.
• CLS (Cumulative Layout Shift): How much the layout shifts while loading. A score above 0.1 means things are jumping around on screen. Reserve space for images and ads to prevent this.

Check image compression

Uncompressed images are one of the most common and most fixable speed issues out there. Switch to modern formats like WebP where you can. The performance gains are real and the effort is low. That's a rare combination.

4. Mobile Usability

Say your client comes to you with a site that looks great on desktop but falls apart on a phone. Small text, overlapping buttons, content wider than the screen. Here's the kicker — Google indexes the mobile version of your site first. A broken mobile experience hurts your rankings across the board, desktop included.

Check the Mobile Usability report

Inside Google Search Console, the Mobile Usability report flags specific pages with specific problems. It won't leave you guessing. Look for text that's too small to read, clickable elements that are too close together, and content that overflows the screen.

Check tap target sizes

Buttons and links need to be large enough to tap without accidentally hitting something nearby. Google recommends at least 48x48 pixels. Anything smaller and you're creating friction every time someone tries to use your site on a phone.

5. Structured Data

Structured data is code that helps search engines understand exactly what your content is about. Done right, it can also unlock rich results — FAQ dropdowns, review stars, product prices — directly in the search results. That's free real estate.

See what you're working with

Use Google's Rich Results Test to paste any URL and see which structured data types are detected and whether they have errors. Most sites have more gaps here than they realize.

Match schema type to content type

• Articles: use Article schema
• Local businesses: use LocalBusiness schema
• Products: use Product schema
• FAQs: use FAQPage schema

Fix validation errors before anything else. Missing required fields or invalid values will block rich results from showing up even when your schema is otherwise correct.

6. Internal Linking

Internal links are how you connect your pages to each other. They help search engines map your site structure and move authority from strong pages to ones that need a boost. Ignoring internal linking is like having a great library with no catalog system.

Find your orphan pages

An orphan page has no internal links pointing to it. Search engines may never find it. Users definitely won't stumble into it. Run a crawl with a tool like Screaming Frog or Sitebulb to surface these hidden dead ends.

Fix your anchor text and link depth

Anchor text tells search engines what the destination page is about. "Click here" tells them nothing. Use descriptive phrases that reflect the actual topic of the page you're linking to. And keep important pages reachable within three clicks from the homepage — anything buried deeper gets crawled less and tends to rank worse.

What to Fix First

A thorough audit almost always turns up more than you can fix at once. That's normal. What matters is working in the right order.

1. Fix crawling and indexation blockers first. These are the only issues that can make your content completely invisible to search engines. Everything else is secondary.
2. Address Core Web Vitals failures next. Google weights these in rankings and they directly affect real user experience.
3. Tackle mobile usability problems. The majority of web traffic is mobile. This is non-negotiable.
4. Then improve structured data and internal linking. High-impact, but only after the critical issues are resolved.

Where to Start

Run this audit on a quarterly schedule. Small problems become large ones fast — especially after site updates, migrations, or platform changes. Start with Google Search Console since it's free, gives you real data, and surfaces many of the issues above without any extra setup.

From there, use a crawler like Screaming Frog for a deeper look at redirect chains, orphan pages, and internal link structure. Pair it with PageSpeed Insights for your Core Web Vitals scores and the Rich Results Test for structured data. You don't need a massive tool stack — you need the right ones used consistently.

If you want audit findings organized alongside your rank tracking and reporting in one place, Aergos (aergos.ai) is worth a look.

The sites that rank well aren't always the ones with the best content. They're the ones with solid foundations that let their content actually get seen. A technical SEO audit is how you build that foundation — and keep it.