Technical SEO Services: What Should an Audit Cover?

You can publish brilliant content, target the right keywords and earn authoritative backlinks, but if search engines struggle to access, understand or index your website, your organic performance can still suffer.

That’s where technical SEO services come in.

Technical SEO focuses on the foundations that allow search engines to discover and process your website effectively. That can mean investigating whether important pages are crawlable, understanding what’s actually being indexed, improving site performance, reviewing internal linking, checking canonicalisation and ensuring structured data is implemented correctly.

Some technical SEO problems are obvious. A page accidentally set to noindex, for example, has a fairly clear consequence.

Others are much less visible.

A large ecommerce site might allow search engines to crawl thousands of unnecessary filtered URLs. A JavaScript-heavy website might present important content differently to users and search engines. A migration could leave redirect chains scattered across the site. Duplicate URLs might send conflicting indexing signals.

The website can appear perfectly normal while technical issues quietly limit its organic potential.

That’s why a proper technical SEO audit should do more than feed your domain into a tool and export every warning it finds.

It should identify the problems that actually matter, explain why they matter and prioritise fixes according to their potential impact.

In this guide, we’ll explain what technical SEO services involve, what a comprehensive audit should cover and what you should expect from the recommendations that follow.

What Is Technical SEO?

Technical SEO is the process of improving a website’s technical foundations so search engines can efficiently crawl, understand, index and serve its content.

It sits alongside other important areas of SEO, including content, on-page optimisation and authority building.

Think of it this way.

Your content tells search engines and users what your pages are about.

Your authority signals help demonstrate why your site might deserve visibility.

Technical SEO helps ensure search engines can access and process those pages correctly in the first place.

Those areas overlap significantly, which is why technical SEO shouldn’t be treated as an isolated checklist for developers.

Decisions involving site architecture, internal links, page templates, navigation, JavaScript and website performance can all affect both search engines and real users.

What Are Technical SEO Services?

Technical SEO services are specialist activities designed to identify and resolve technical factors affecting a website’s organic search performance.

Depending on the website and provider, that might include:

• Technical SEO audits
• Website crawling
• Crawlability analysis
• Indexation analysis
• Robots.txt reviews
• XML sitemap optimisation
• Canonicalisation
• Duplicate content investigation
• Redirect audits
• Broken-link analysis
• Internal linking
• Site architecture
• JavaScript SEO
• Page performance
• Core Web Vitals
• Mobile SEO
• Structured data
• International SEO
• Website migration support
• Technical monitoring

Not every website needs the same work.

A local service business with a relatively small brochure website has very different technical requirements from an international ecommerce business with hundreds of thousands of URLs.

Good technical SEO starts by understanding the website rather than applying the same audit template to everything.

What’s the Difference Between a Technical SEO Audit and a General SEO Audit?

A full SEO audit usually examines a broader range of factors.

That can include technical health alongside:

• Keyword targeting
• Content quality
• Search intent
• Metadata
• On-page optimisation
• Backlinks
• Competitor performance
• Organic visibility

A technical SEO audit goes deeper into the infrastructure and technical signals that influence how search engines access and interpret the website.

There’s naturally some crossover.

Internal linking, for example, affects crawlability but is also an important content and UX consideration. Site speed is technical, but it directly affects users too.

The distinction is less important than making sure the right questions are actually being investigated.

Why Does Technical SEO Matter?

Search engines need to perform several steps before your page can appear in search results.

They need to discover it.

They need to access it.

They need to process and understand it.

And, where appropriate, they need to index it.

Technical SEO helps remove unnecessary barriers throughout that process.

Great Content Can’t Compensate for Every Technical Problem

Imagine you’ve created the best page in your market for a valuable search query.

If that page is accidentally blocked from indexing, its quality won’t rescue it.

Likewise, if Google discovers dozens of duplicate versions and receives conflicting canonical signals, you’re creating unnecessary ambiguity around which version should appear in search.

Technical SEO helps ensure your other SEO work has solid foundations.

Technical Problems Scale

One of the reasons technical SEO becomes particularly important on larger websites is that template-level problems can affect enormous numbers of URLs.

A mistake on one page is one problem.

A mistake in a template used across 50,000 product pages is a very different problem.

This is why technical SEO specialists often look for patterns rather than individual errors.

What Should a Technical SEO Audit Cover?

A strong technical SEO audit should follow the way search engines encounter and process a website.

That means investigating questions such as:

1. Can search engines discover our important URLs?
2. Can they crawl them?
3. Are they allowed to index them?
4. Which URLs are actually being indexed?
5. Are we sending consistent signals about preferred URLs?
6. Can search engines understand the content?
7. Is the site architecture helping or hindering discovery?
8. Does the website perform effectively for users?
9. Are enhanced search features implemented correctly?
10. Are technical problems concentrated in particular templates or sections?

Let’s break those areas down.

1. Crawlability

Crawling is the process search engines use to discover and access pages on the web.

A technical SEO audit should establish whether search engine crawlers can efficiently reach the pages you want them to find.

Robots.txt

The robots.txt file provides instructions about which areas crawlers should or shouldn’t access.

An audit should check for unintended restrictions.

A simple configuration mistake can prevent crawlers from accessing important areas of a website.

But the opposite can also be a problem.

Allowing search engines to spend time crawling large numbers of low-value URLs can create inefficiency, particularly on very large websites.

Internal Links

Search engines discover pages partly by following links.

That means your internal linking structure is a technical SEO consideration as well as a usability one.

An audit should investigate questions such as:

• Can important pages be reached through internal links?
• How deep are priority pages within the site?
• Are important pages effectively orphaned?
• Are internal links pointing through redirects?
• Are there broken internal links?
• Does anchor text provide useful context?
• Are low-value pages receiving disproportionate internal authority?

Your most commercially important content shouldn’t require a search engine to solve a maze before reaching it.

Crawl Depth

Crawl depth describes how many steps a page sits from a starting point such as the homepage.

A deep URL isn’t automatically bad.

Large websites naturally have complex hierarchies.

But if strategically important pages are buried unnecessarily deep while low-value pages dominate navigation, the architecture may need attention.

Crawl Traps and Infinite URL Spaces

Some websites can inadvertently generate enormous numbers of URLs.

Common causes include:

• Faceted navigation
• Filters
• Parameters
• Internal search
• Calendars
• Sorting options
• Session identifiers

On a large ecommerce website, combinations of colour, size, price, brand and sorting filters can potentially create huge numbers of crawlable URLs.

Technical SEO needs to determine which variations have genuine search value and which simply create noise.

2. Indexation

Crawling and indexing are related, but they’re not the same thing.

A search engine may crawl a URL without indexing it.

A technical audit should therefore investigate what search engines are actually choosing to index.

Which Pages Should Be Indexed?

The objective isn’t to get every URL indexed.

The objective is to have the right URLs indexed.

Depending on your website, pages that may not warrant independent indexation could include:

• Internal search results
• Duplicate filtered pages
• Staging URLs
• Utility pages
• Account areas
• Thin tag pages
• Duplicate parameter URLs

The precise answer depends on the site.

A technical SEO specialist should distinguish intentional exclusions from genuine problems.

Noindex Directives

A noindex directive tells search engines not to include a page in their index.

There are plenty of legitimate reasons to use one.

The problem arises when valuable pages receive the directive accidentally.

Audits should therefore look for unexpected noindex implementation and confirm whether excluded pages match the intended SEO strategy.

Google Search Console

Crawler tools show how a website is configured.

Google Search Console provides another important perspective: how Google itself is processing it.

Indexing reports can help identify patterns involving:

• Indexed URLs
• Excluded URLs
• Crawled but currently unindexed pages
• Discovered but currently unindexed pages
• Duplicate URLs
• Redirected URLs
• Errors

These reports need interpretation.

An excluded URL isn’t automatically an SEO problem. Sometimes exclusion is exactly what you intended.

3. XML Sitemaps

An XML sitemap provides search engines with a structured list of URLs you want them to know about.

A technical SEO audit should check whether your sitemap:

• Exists
• Is accessible
• Contains the correct URLs
• Avoids non-indexable URLs
• Avoids redirects
• Avoids 404 pages
• Uses appropriate canonical URLs
• Is updated when content changes
• Is submitted appropriately to search engines

For larger sites, separate sitemaps can also make monitoring easier by allowing SEOs to compare indexation across different content types.

For example, an ecommerce site might separate:

• Products
• Categories
• Blog content
• Other landing pages

The sitemap isn’t a substitute for good internal linking.

It’s an additional discovery and monitoring mechanism.

4. Canonicalisation and Duplicate URLs

It’s common for multiple URLs to contain identical or very similar content.

That can happen because of:

• URL parameters
• Product variants
• Tracking parameters
• Sorting
• Filters
• HTTP and HTTPS versions
• WWW and non-WWW versions
• Trailing-slash variations
• Duplicate category paths

Canonicalisation helps search engines understand which URL you consider the preferred version.

What Should an Audit Check?

Technical SEO services should investigate whether:

• Canonical tags exist where appropriate
• Canonicals point to valid URLs
• Important pages canonicalise to themselves where appropriate
• Canonical signals conflict with redirects or internal links
• Duplicate URLs are being generated unnecessarily
• HTTP and HTTPS behaviour is consistent
• Internal links consistently use preferred URLs

Canonical tags shouldn’t be used as a sticking plaster for a chaotic URL structure.

Where possible, the underlying causes of duplication should also be considered.

5. HTTP Status Codes, Broken Pages and Redirects

When a browser or search engine requests a URL, the server responds with an HTTP status code.

Technical SEO audits commonly examine:

• 200 – successful request
• 301 – permanent redirect
• 302 – temporary redirect
• 404 – page not found
• 5xx – server errors

The objective isn’t to eliminate every non-200 status code.

Redirects and 404s have legitimate uses.

The goal is to make sure they’re being used correctly.

Broken Internal Links

Internal links leading to 404 pages create unnecessary dead ends for users and crawlers.

They should normally be updated to an appropriate live destination where one exists.

Redirect Chains

A redirect chain occurs when one URL redirects to another URL, which redirects again.

For example: URL A → URL B → URL C

Rather than making users and crawlers travel through unnecessary steps, internal links should generally point directly to the final destination.

Redirect Loops

Redirect loops occur when redirects create a cycle that never reaches a working destination.

These need fixing.

Soft 404s

A page can technically return a successful 200 response while effectively behaving like a missing page.

Search engines may interpret these as soft 404s.

A technical audit should identify patterns where error handling and server responses don’t accurately reflect the content being served.

6. Site Architecture

Site architecture describes how pages are organised and connected.

Good architecture helps users navigate the website while giving search engines logical routes through your content.

Technical SEO analysis may consider:

• Page hierarchy
• Navigation
• Categories and subcategories
• URL structure
• Internal linking
• Breadcrumbs
• Crawl depth
• Orphan pages

Architecture Should Reflect Importance

Your most important pages should generally have strong internal connections.

If an important commercial landing page receives one obscure link while an outdated page is linked globally from every template, your internal structure may be sending the wrong signals.

Architecture isn’t simply about making everything reachable.

It’s about creating meaningful relationships between pages.

7. Website Performance and Core Web Vitals

Website performance affects user experience and is therefore an important part of technical SEO.

Slow pages create friction.

People may abandon a website before they can read the content, view a product or submit an enquiry.

A technical audit should look beyond a single “speed score” and investigate what’s actually causing performance problems.

Potential issues include:

• Oversized images
• Unoptimised video
• Excessive JavaScript
• Third-party scripts
• Render-blocking resources
• Font loading
• Inefficient code
• Poor caching
• Server response times
• Heavy plugins or apps

Core Web Vitals

Core Web Vitals are Google’s metrics for aspects of real-world page experience.

The current set focuses on:

• Largest Contentful Paint (LCP) – how quickly the main content becomes visible.
• Interaction to Next Paint (INP) – how responsive the page is when a user interacts with it.
• Cumulative Layout Shift (CLS) – how visually stable the page remains while loading.

These metrics shouldn’t be treated as abstract scores to chase for their own sake. They represent genuine aspects of user experience.

Lab Data vs Real-World Data

Performance tools can provide controlled test data, while real-user data reflects how actual visitors experience a website across different devices and connections.

Both can be useful.

A good technical audit understands the distinction rather than relying on one screenshot from a speed-testing tool.

8. Mobile SEO

Modern websites need to work properly on mobile devices.

Technical SEO should therefore investigate whether the mobile experience creates problems for users or search engines.

That can include:

• Responsive behaviour
• Content parity
• Navigation
• Font sizes
• Touch targets
• Intrusive elements
• Performance
• Images
• Interactive functionality

Mobile optimisation isn’t simply making a desktop website narrower.

Content and functionality need to remain usable on smaller screens and touch-based devices.

9. JavaScript SEO

Modern websites increasingly use JavaScript to create interactive experiences and load content dynamically.

There’s nothing inherently wrong with that.

But JavaScript can make technical SEO more complex.

An audit may need to determine:

• Whether important content is available to search engines
• Whether internal links are implemented in a crawlable way
• Whether metadata is rendered correctly
• Whether rendering creates significant delays
• Whether client-side routing creates indexing problems
• Whether search engines and users receive materially different content

View the Site Like a Search Engine

For JavaScript-heavy websites, looking at what appears visually in your browser isn’t always enough.

Technical specialists may compare raw HTML, rendered HTML and crawler output to understand when and how important content becomes available.

The question isn’t: Does this page work on my laptop?

It’s: Can search engines reliably access and interpret everything they need?

10. Structured Data

Structured data provides machine-readable information that helps search engines understand particular entities and content types on a page.

Schema.org vocabulary can be used to describe things such as:

• Products
• Organisations
• Articles
• Breadcrumbs
• Events
• Local businesses
• Job postings
• Recipes

Where supported by search engines, appropriate structured data can also make pages eligible for particular search-result features.

What Should a Structured Data Audit Check?

A technical SEO audit should assess:

• Whether relevant structured data is present
• Whether the implementation is valid
• Whether required properties are included
• Whether markup accurately reflects visible content
• Whether duplicate or conflicting schema exists
• Whether template-level implementation creates errors at scale

Structured data isn’t a way to trick search engines into giving you better rankings.

It should accurately describe what genuinely exists on the page.

11. HTTPS and Website Security Signals

Users and search engines should be able to access your website securely over HTTPS.

A technical audit may investigate:

• HTTP URLs that remain internally linked
• HTTP-to-HTTPS redirects
• Mixed content
• Incorrect canonical URLs
• Sitemap inconsistencies
• Security certificate issues

An HTTPS migration that was only partially completed can leave a website sending inconsistent signals.

The preferred version should be clear throughout internal links, redirects, canonicals and sitemaps.

12. International SEO

Businesses operating across multiple countries or languages have additional technical considerations.

A technical SEO audit may need to examine:

• Country and language URL structures
• Hreflang implementation
• Canonicalisation
• International internal linking
• Duplicate or translated content
• Localised sitemaps
• Redirect behaviour

Hreflang

Hreflang annotations help search engines understand language or regional alternatives of a page.

They can be extremely useful.

They can also be implemented incorrectly at scale.

Common issues include:

• Missing return links
• Invalid language or country codes
• Links to redirected URLs
• Links to non-indexable pages
• Conflicts with canonical tags
• Missing page variants

International SEO is an area where apparently small technical mistakes can affect large sections of a website.

13. Ecommerce Technical SEO

Ecommerce websites often introduce their own technical challenges.

A product catalogue can generate thousands or millions of URLs through combinations of:

• Products
• Variants
• Collections
• Categories
• Pagination
• Filters
• Sorting
• Internal search
• Tracking parameters

A technical SEO strategy needs to determine which URLs deserve search visibility and how search engines should handle the rest.

Faceted Navigation

Faceted navigation allows customers to filter product listings by attributes such as:

• Size
• Colour
• Brand
• Price
• Material
• Rating

It’s brilliant for users.

Without careful technical planning, however, it can generate enormous numbers of crawlable URL combinations.

Some filtered pages may represent valuable search demand.

Others may create near-duplicate pages with no independent search value.

The correct approach therefore isn’t necessarily “block all filters”.

It’s understanding which pages serve a useful search purpose.

[h4] Out-of-Stock and Discontinued Products

Ecommerce audits should also investigate what happens when products disappear.

Automatically deleting every unavailable product can waste existing rankings, backlinks and customer demand.

The appropriate response depends on whether the product is temporarily unavailable, permanently discontinued or replaced by something else.

Technical decisions need commercial context.

14. Website Migrations

Technical SEO becomes particularly important when a website is redesigned, replatformed or moved to a new domain.

A migration can change:

• URLs
• Site architecture
• Internal links
• Content
• Metadata
• Rendering
• Canonicalisation
• Structured data
• Page performance

Changing several of these at once creates risk.

Technical SEO Before Migration

Before launch, specialists should understand the existing website.

That may involve collecting:

• Current URLs
• Organic landing pages
• Rankings
• Backlinks
• Traffic
• Conversions
• Indexation data

Redirect mapping should then determine where valuable old URLs will go.

Technical SEO After Migration

Once the new website launches, checks should continue.

A post-launch audit may review:

• Redirects
• 404 errors
• Indexability
• Robots directives
• Canonicals
• Sitemaps
• Internal links
• Analytics
• Search Console data
• Rankings
• Organic traffic

Migration SEO isn’t one spreadsheet created before launch.

It’s a process that continues until the new site has settled and important issues have been addressed.

15. Log File Analysis

For larger or technically complex websites, server log files can provide valuable information about how search engine crawlers actually interact with the site.

Crawler software tells you what could be crawled.

Log files can help show what bots are actually requesting.

Analysis can help answer questions such as:

• Which URLs is Googlebot crawling?
• How frequently?
• Are important sections receiving crawler attention?
• Is significant crawling being spent on low-value URLs?
• Are crawlers repeatedly encountering errors?

Log analysis isn’t necessary for every website.

But for very large sites, it can provide a level of visibility that conventional crawls alone can’t.

Technical SEO Tools: What Do Specialists Use?

Technical SEO usually involves combining several sources rather than relying on one tool.

Common tools include:

Google Search Console

Provides first-party information about how Google interacts with your website, including search performance, indexation and page experience data.

Screaming Frog SEO Spider

A specialist website crawler used to analyse elements such as status codes, metadata, canonicals, directives, internal links and structured data.

Sitebulb

Another specialist crawler with strong technical reporting and visualisation capabilities.

PageSpeed Insights and Lighthouse

Useful for investigating website performance and identifying potential improvements.

Ahrefs and Semrush

Broader SEO platforms that can contribute data around technical health, organic performance, backlinks, keywords and competitor visibility.

The important point isn’t how many tools your SEO provider owns.

It’s whether they know how to interpret the data.

ZEAL’s existing SEO approach combines crawler information with first-party Search Console data for precisely this reason: what matters isn’t simply what an audit tool flags, but what search engines can actually access and index.

Why Automated Technical SEO Audits Aren’t Enough

Type your domain into most SEO platforms and, within minutes, you’ll have a list of problems.

That’s useful, it isn’t necessarily an audit. Automated crawlers are extremely good at collecting information and identifying patterns. They aren’t always good at understanding context.

A tool might flag: 500 pages have missing meta descriptions.

A specialist should ask: What are these pages? Should they be indexed? Do they generate traffic? Are descriptions actually the priority?

A crawler might report: 2,000 URLs are blocked by robots.txt.

The real question is: Should they be blocked?

The difference between a useful technical audit and an automated report is interpretation.

How Should Technical SEO Issues Be Prioritised?

A 100-page audit isn’t particularly valuable if nobody knows where to start.

Technical recommendations should be prioritised.

A useful framework considers:

• Impact
  How much could fixing the issue improve organic performance or user experience?
• Scale
  Does the problem affect one URL or 100,000?
• Confidence
  How strong is the evidence that this is genuinely a problem?
• Effort
  How difficult is the fix?
• Risk
  Could making the change create unintended consequences?

This helps separate genuine priorities from background noise.

For example, fixing an accidental noindex directive across an important product category may deserve immediate attention. Rewriting 200 perfectly functional URLs because an audit tool considers them slightly long probably doesn’t.

Technical SEO isn’t about achieving a perfect audit score, it’s about making changes that matter.

What Should You Receive from a Technical SEO Audit?

A technical SEO audit should leave you knowing what to do next.

At minimum, useful deliverables should include:

• A summary of the site’s technical health
• Clearly documented findings
• Evidence supporting each significant issue
• Examples of affected URLs
• An explanation of why the problem matters
• Recommended fixes
• Prioritisation
• Guidance for developers where required

For complex problems, recommendations may need to include acceptance criteria so development teams can confirm when the work has been implemented correctly.

The Audit Should Speak Human Too

Not everybody reading the report will be an SEO specialist.

Decision-makers need to understand the business impact.

Developers need enough technical detail to implement the fix.

SEO teams need evidence and priorities.

A good audit communicates appropriately to all three.

How Often Should You Run a Technical SEO Audit?

There’s no universal schedule.

A relatively small, stable website may not require constant deep auditing.

A large ecommerce website deploying changes every week needs closer monitoring.

You should particularly consider a technical audit:

• At the beginning of an SEO strategy
• Before a redesign
• Before and after a migration
• After major development changes
• Following unexplained organic traffic loss
• After significant changes to site architecture
• When entering international markets
• When technical debt has accumulated
• When the site hasn’t been reviewed for a long time

Regular monitoring can also identify issues before they become significant.

The objective isn’t to repeatedly generate the same report.

It’s to understand whether the technical health of the website is changing.

How Do Technical SEO Specialists Work with Developers?

Technical SEO recommendations often require development work.

That makes collaboration critical.

Simply sending developers a spreadsheet containing 200 SEO errors isn’t particularly effective.

A better process is:

1. Identify and investigate the problem.
2. Establish its impact.
3. Discuss potential solutions with development.
4. Agree the implementation.
5. Deploy safely.
6. Test the change.
7. Monitor the outcome.

Developers may also identify constraints or better technical solutions that weren’t obvious during the audit.

SEO specialists should therefore explain the desired outcome rather than treating implementation as a one-way instruction.

The strongest technical SEO work tends to happen when SEO and development teams solve problems together.

Technical SEO Is About Removing Barriers

Technical SEO can become complicated quickly. There are status codes, directives, canonicals, rendering, schema, sitemaps, Core Web Vitals and enough acronyms to make almost any meeting unnecessarily confusing.

But underneath all of that, the objective is relatively simple.

Make it as easy as possible for search engines to access, understand and correctly index the content you want people to find.

A good technical SEO audit identifies what stands in the way of that objective, a great one goes further. It separates significant problems from harmless warnings, connects recommendations to their likely impact and gives your SEO and development teams a realistic plan for making the website better. That’s what effective technical SEO services should provide, not a 200-page export of everything a crawler can find.

Technical SEO Expertise You Can Trust

At ZEAL, our technical SEO work combines specialist crawling, first-party search data and human analysis to understand how websites are actually being discovered and processed. We then prioritise the changes that can make a meaningful difference, working alongside content, development and wider digital teams rather than treating technical SEO as an isolated exercise.

If you’re unsure whether technical issues are limiting your organic performance, preparing for a website migration or simply need a clearer picture of your site’s technical health, get in touch with ZEAL to discuss a technical SEO audit.