Technical audit
Technical SEO audit: a practical guide
Find and fix the technical problems that hold back your rankings: crawling, indexing, performance, JavaScript rendering, architecture. The Zerkado audit checks for 51 issue types.
Key features
What this module does, in practice.
Indexability
Robots.txt, sitemap, canonical tags, noindex and hreflang: what keeps Google from indexing your pages.
Core Web Vitals
Lab measurement of LCP, CLS and TBT on a sample of pages, plus the response time of every page.
Full crawl
4xx and 5xx errors, broken links, redirect chains and loops, pages that are too deep or orphaned.
JavaScript rendering
As an option, the crawl executes JavaScript to see the content generated in the browser.
What is a technical SEO audit?
A technical SEO audit examines your website's infrastructure to check that it meets search engine requirements. Technical SEO isn't a box to tick: it's the foundation that content and links rest on.
Unlike editorial work or link building, technical SEO deals with aspects visitors never see but that are decisive for search engine crawlers. Great content won't rank if Google can't find it, read it or understand it.
Crawling and indexing: the basis of visibility
Google discovers a website in two stages: crawling, then indexing. The technical audit checks that both go smoothly.
Optimizing crawl budget
Crawl budget is the number of pages Googlebot can and wants to crawl on your website in a given time. Google notes that it mainly matters for very large websites and for those whose pages change often. For those, you block crawling of pages with no search value (via robots.txt) and remove redirect chains, which waste requests.
Managing indexing
A crawled page still has to be indexed to appear in search results. Meta robots tags (index, noindex) and canonical tags play a key role here. Duplicate content is a common mistake: Google has to choose which version to keep, and it isn't always the one you'd prefer.
The most common technical SEO errors (in French)The technical errors that hurt rankings, and how to fix them.Core Web Vitals and performance
Core Web Vitals are part of the page experience signals Google takes into account. They measure the real experience of visitors through three metrics.
| Metric | What it measures | Google's "good" threshold |
|---|---|---|
| LCP (Largest Contentful Paint) | How long the main content takes to display | 2.5 seconds or less |
| INP (Interaction to Next Paint) | How quickly the page responds to interactions | 200 milliseconds or less |
| CLS (Cumulative Layout Shift) | Visual stability while the page loads | 0.1 or less |
Improving these metrics often takes technical work: caching, optimized images (WebP, AVIF), lighter CSS and JavaScript, a CDN. Zerkado measures LCP and CLS on a sample of pages with every crawl. INP requires real visitors, so in the lab the tool measures TBT instead, the proxy Google itself uses. Field data is still available in Search Console.
Architecture and internal linking
Your website's architecture determines how authority flows between your pages through internal links. A topic-based structure groups related content and strengthens your pillar pages.
Page depth
A common rule of thumb: an important page shouldn't be more than three clicks from the home page. The technical audit flags orphan pages (no internal link leads to them) and pages that are too deep, which bots crawl less easily.
Internal linking strategy (in French)How to build internal linking that strengthens your key pages.Security and mobile compatibility
HTTPS is a prerequisite today. A technical audit checks that the certificate is valid, that there's no mixed content (HTTP resources loaded on an HTTPS page) and that security headers such as HSTS are configured.
Mobile-first indexing
Google indexes websites based on their mobile version. Yours must therefore display properly on smartphones: no blocking elements, tap targets large enough, and text readable without zooming.
Structured data and Schema.org
Structured data (Schema.org) describes a page's content in a format search engines understand. It can make the page eligible for certain rich results (reviews, prices, breadcrumbs, events…), with no guarantee they'll be shown: Google decides case by case, and has reduced the number of types it displays in recent years.
The main markup types
| Schema.org type | Use | Difficulty | Display in Google |
|---|---|---|---|
| FAQPage | Questions and answers | Easy | Limited since 2023 to authoritative government and health websites |
| HowTo | Step-by-step guides | Medium | No longer shown as a rich result since 2023 |
| Article | Blog posts and news articles | Easy | Helps Google understand the title, image and date |
| SoftwareApplication | Software and apps | Medium | Can show rating and price |
| Review / AggregateRating | Reviews and ratings | Medium | Stars possible, under conditions (not for reviews of your own business) |
| Organization | Company identity | Easy | Helps Google identify the company's logo and details |
The Zerkado audit lists the Schema.org types found on each page, and flags pages without any and unreadable JSON-LD blocks that Google can't use.
Online tool or desktop software: Zerkado, Screaming Frog, Sitebulb
The right tool depends on your profile (independent consultant, agency, in-house team) and the size of the websites you audit. Desktop software such as Screaming Frog SEO Spider or the desktop version of Sitebulb remain benchmarks. The table compares how they work, as of the time of writing (October 2026); check current offers on each vendor's website.
| Criterion | Desktop software (Screaming Frog, Sitebulb…) | Zerkado |
|---|---|---|
| Where the crawl runs | On your computer | On Zerkado's servers |
| Website size | Depends on the license and the machine's power | Depends on the plan, up to 200,000 pages |
| JavaScript rendering | Yes, with a built-in browser | Yes, as an option (headless browser on our servers) |
| Scheduled crawls | Possible depending on the tool; the computer must stay on | Every 7 days by default, at most every 6 days |
| Depth of analysis | Very detailed: many settings and custom extractions | 51 issue types, each with its fix guide |
| Rankings and backlinks | Through connections to third-party services | In the same tool |
| Client reports | Exports; white label depending on the tool | White-label reports from the Pro plan |
| Price | License, often annual; limited free version for some | Audit included from €79/month |
Screaming Frog remains an excellent tool for one-off, highly detailed audits. Zerkado meets a different need: crawling several websites from its servers at regular intervals, and linking the issues found to rankings and client reports.
Technical audit tools
A complete technical audit relies on tools that can reproduce how search engines behave and analyze a large number of pages.
Google Search Console is essential: it gives you data from Google itself (indexing, performance, Core Web Vitals measured on your visitors). It's less suited to systematic, page-by-page checks. That's the job of a crawler: Zerkado crawls your website from its servers, within your plan's page limit, executing JavaScript if you enable it, to see your pages the way a search engine does.
Discover the Zerkado SEO platformAudit, rankings, backlinks, AI content and white-label reports: all the modules of the platform.Technical audit checklist
To structure your next audit, here are the points to check first:
- Check the robots.txt file and crawl directives
- Analyze HTTP status codes (4xx and 5xx errors)
- Review canonical tags and find duplicate content
- Validate hreflang tags (multilingual websites)
- Measure Core Web Vitals (LCP, INP, CLS)
- Check mobile compatibility and usability
- Analyze URL structure and breadcrumbs
- Validate structured data with Google's Rich Results Test
To go further, read our SEO audit guide, or follow the effect of your technical fixes with rank tracking.
Discover the complete SEO platformThe technical audit is one module among 9. Zerkado brings audit, rankings, backlinks, content and reports together in one platform.Frequently asked questions
The questions we hear most often.
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