SEO audit vs website performance test: what each one checks, and when you need both

An SEO audit and a website performance test are often mentioned in the same breath, and often confused. They answer different questions. An SEO audit asks whether search engines can find, crawl, index and understand your pages. A performance test asks how quickly a page loads and responds for a visitor. One is about being found; the other is about what happens after the click.

This guide compares the two, lists the tools for a technical SEO audit, gives you a website auditing checklist, and explains the ideas that come up along the way: common SEO errors, mobile-first indexing, user experience metrics, SEO versus SEM, and crawl budget.

SEO audit vs website performance test: how they compare

The table sets the two side by side.

They overlap in one place. Core Web Vitals are part of how Google evaluates page experience, so a performance problem can also be an SEO problem, although relevance and content quality matter far more for rankings. A full website audit therefore includes performance as one of its parts.

Neither replaces the other. A fast page carrying a leftover noindex won't appear in search at all. A perfectly indexed page that takes eight seconds to show its main content on a phone will lose the visitor it worked to earn.

Tools for a technical SEO audit

You don't need a paid suite to start. These cover the essentials, and most are free.

Indexing, crawling and links

• Google Search Console. The starting point. The Page indexing report shows which URLs are indexed and why others aren't, URL Inspection shows how Google sees a single page, and the Core Web Vitals and Crawl stats reports cover speed and crawling.
• Bing Webmaster Tools. The equivalent for Bing, with its own site scan.
• A site crawler. Follows your internal links the way a search engine does and reports problems page by page. Rudra's site crawl, which you can start from the demo page, checks titles, descriptions, headings, canonicals, indexing directives and broken internal links on each page it crawls. The free plan covers up to 2 websites, with up to 10 pages per scan.
• A single-page SEO check. Rudra's free SEO checker reviews one page's on-page signals plus the site's robots.txt and sitemap. It reads the HTML your server returns, so for content added later by JavaScript, check the rendered HTML in URL Inspection as well.
• A broken link checker. The broken link checker tests links on a page and reports your own scripts, images and fonts that fail to load.

Speed and structured data

• PageSpeed Insights. Shows field data from real Chrome users, where enough exists, above a Lighthouse lab test.
• Lighthouse. Built into Chrome DevTools. Rudra's website speed checker runs it for you and lists the audits that didn't pass, worst first.
• Rich Results Test. Checks whether your structured data makes a page eligible for rich results.

Paid suites add things a crawler can't see: backlink data, keyword rankings and competitor research. Rudra doesn't do those. They're worth paying for once the technical basics are fixed, not before.

A website auditing checklist

Work through these in order. The early items decide whether the later ones matter: there's no point polishing a page that can't be indexed.

Crawling and indexing

1. The site is verified in Google Search Console and an XML sitemap is submitted.
2. robots.txt doesn't block pages you want found. A leftover Disallow: / from a staging site is a common cause of a site that never appears.
3. No important page carries noindex in a robots meta tag or an X-Robots-Tag header. See what noindex means.
4. Important pages return HTTP 200, and missing pages return a real 404 rather than a "not found" message with a 200 status.
5. The sitemap lists only live, indexable URLs. See how to diagnose sitemap problems.

On-page

1. Every indexable page has a unique, descriptive title and meta description.
2. One clear H1 per page, followed by H2 and H3 headings in order.
3. Each page's canonical tag is absolute and points to its preferred URL.
4. HTTP redirects to HTTPS, and the www and non-www versions resolve to one address in a single hop.
5. No broken internal links, and no important page left unlinked.
6. Structured data parses and matches what's visible on the page.

Speed and mobile

1. In field data, LCP is 2.5 s or less, INP 200 ms or less and CLS 0.1 or less at the 75th percentile.
2. Images are compressed, sized for their display and given explicit width and height.
3. A viewport meta tag is set, text is readable without zooming, and nothing scrolls sideways.
4. The mobile page carries the same content, headings and structured data as the desktop page.

Trust and function

1. HTTPS on every page, a valid certificate and no mixed content.
2. Forms have labels and work on a phone; submit each one yourself to confirm it arrives.
3. Images have meaningful alt text, and color contrast is sufficient.

Record what you find with a date, fix the indexing items first, and repeat the audit once the fixes have been live for a few weeks.

Common website SEO errors

The same faults turn up on most sites. Nearly all are simple to fix once someone has noticed them.

Crawling and indexing errors

• A leftover noindex or robots.txt block from development. The most damaging, because the page simply disappears from search.
• Canonical problems: missing, relative, multiple, or pointing at the wrong URL. See how to fix canonical problems.
• The same page at several addresses: http and https, with and without www, with tracking parameters.
• Soft 404s: a "not found" page served with 200 OK.
• Broken internal links and redirect chains left behind when pages are renamed or removed.
• Orphan pages that nothing links to, so crawlers reach them only through the sitemap, if at all. See how to find orphan pages.
• A sitemap full of redirected, blocked or deleted URLs.

On-page and content errors

• Duplicate or missing titles and descriptions. Often caused by a template that outputs the same text on every page. See how to fix duplicate titles.
• Thin pages with a heading and a line or two of text.
• Missing or skipped headings, such as no H1 or an H2 followed directly by an H4.
• Images without alt text, and important text placed inside images.
• Content that's on desktop but missing on mobile.
• Invalid structured data that doesn't parse or is missing key properties. See how to check structured data.

The importance of mobile-first indexing

Mobile-first indexing means Google mainly crawls and indexes the mobile version of your pages. The desktop version is no longer the reference. If a heading, a paragraph, an image or a block of structured data is missing from the mobile page, then as far as Google is concerned it's missing from the page.

That changes how you audit. Check the mobile results first, and treat your mobile site as your site:

• Use a responsive design, so one URL serves the same HTML to every screen size.
• Keep the same text, headings, images, alt text, structured data and meta tags on mobile as on desktop. Don't shorten pages for small screens.
• Make sure content inside tabs and accordions is in the HTML, not fetched only when tapped.
• Set the viewport meta tag (the snippet is below this list).
• Don't block the CSS, JavaScript or images Google needs to render the page.
• Avoid pop-ups that cover the content as soon as the page opens.
• Test on real phone widths, not just a narrowed desktop window.

<meta name="viewport" content="width=device-width, initial-scale=1">

Rudra's SEO checks flag a missing viewport tag, and the mobile checker renders a page at phone, tablet and desktop widths and flags content that spills off the screen. For the fixes, see how to make a website mobile friendly.

Website user experience metrics

User experience can be measured. Start with Google's three Core Web Vitals, which are taken from real visits:

A page passes when 75% of visits meet each threshold, measured separately for mobile and desktop. Several supporting timings help you find the cause of a poor result:

• Time to First Byte (TTFB): how long the server takes to start responding. It reflects hosting, caching and distance from the visitor.
• First Contentful Paint (FCP): when anything at all first appears.
• Total Blocking Time (TBT): how long the main thread is too busy to respond during loading. It's the closest lab signal to INP.
• Speed Index: how quickly the visible part of the page fills in.

Speed is only part of the experience. Your analytics add the behavioral side:

• Engagement rate and engagement time: are visitors reading, or leaving at once?
• Scroll depth: do they reach the part of the page that matters?
• Conversion rate: of every hundred visitors, how many sign up, buy or get in touch?
• Form abandonment: how many start a form and don't finish it.
• Exit pages: where visitors most often leave.

Accessibility belongs here too. A page that can't be used with a keyboard or a screen reader is a poor experience however fast it loads; see how to improve website accessibility, or test a page with the accessibility checker.

SEO vs SEM: search interest and which to choose

SEO, search engine optimization, is the work of earning unpaid positions in search results. SEM, search engine marketing, originally covered both paid and unpaid search, but in everyday use it now means paid search advertising, where you pay for each click.

Compare the two terms in Google Trends and "SEO" typically draws far more search interest than "SEM". That says more about vocabulary than about the size of the two industries: people looking for paid search tend to type "Google Ads" or "PPC" instead. Google Trends shows relative interest on a scale of 0 to 100, not the number of searches, so use it to compare terms and spot seasonal patterns, and check the current figures for your own country before relying on them.

For most sites the sensible order is SEO first, with paid search added when you need traffic quickly or want to test which searches convert before writing content for them. Either way, audit the landing page first. A paid click that lands on a slow page with a broken form is paid for twice: once for the click, and again in the customer you didn't get.

Website crawl budget explained

Crawl budget is the set of URLs a search engine can and wants to crawl on your site in a given period. Google describes it as the result of two things:

• Crawl capacity limit: how much Googlebot can crawl without overloading your server. Fast, reliable responses raise it; errors and slow responses lower it.
• Crawl demand: how much Google wants to crawl your pages, based on how popular they are and how often they change.

For most websites this isn't a constraint. Google's guidance is that crawl budget is mainly a concern for very large sites (around a million pages or more), for sites with tens of thousands of pages that change daily, or where a large share of URLs sit in Search Console as "Discovered - currently not indexed". A site with a few hundred pages will be crawled in full.

It's still worth understanding, because what wastes crawl budget on a large site is a sign of poor maintenance at any size:

• Duplicate pages reachable at several URLs, including versions with tracking parameters.
• Filter and sort combinations that generate endless URLs for the same content.
• Long redirect chains.
• Soft 404s.
• Slow or failing server responses.
• Sitemaps listing URLs that redirect or no longer exist.

To keep crawling efficient, keep the sitemap accurate, return a real 404 or 410 for removed pages, consolidate duplicates with redirects and canonical tags, and use robots.txt to keep crawlers out of sections with no search value. Remember that robots.txt stops crawling, not indexing; our guide to robots.txt and sitemap.xml explains the difference.

Rudra doesn't measure crawl budget. Only the search engine knows how it spends its time on your site, and the Crawl stats report in Google Search Console (under Settings) is where to look. What a crawl of your own site does show is the waste: redirect chains, broken links, duplicate titles and non-canonical URLs. And if a new page isn't appearing in search, the cause is far more often an indexing or quality issue than crawl budget.

Where to start

1. Run a single-page check on your homepage and one important inner page with the free website audit.
2. Crawl the site to find the problems that only show up across pages.
3. Fix anything that blocks indexing, then work down the list by severity.
4. Run a lab speed test on each main template, and compare it with your field data.
5. Rescan, compare with the earlier results, and repeat every quarter.

If you only need one area checked, the free single-page tools cover SEO, speed, mobile layout, broken links and security.