Website optimisation
[Industry] client
- Starting point
- [Verified baseline]
- What we did
- [Summary of work]
- Outcome
- [Verified results with timeframe]
Website optimisation that makes your site faster, smoother and more profitable
A slow or clumsy website quietly costs you leads, sales and rankings every day. We find what's slowing your site down, fix it properly at the source, and keep it fast as your business adds new pages, features and tools.
Why website performance matters
Every visitor judges your website within seconds. When pages load slowly, jump around as they load, or respond sluggishly to taps and clicks, people lose patience and leave, often before seeing your offer. The effect is strongest on mobile connections, which is how many of your visitors arrive.
Performance problems rarely announce themselves. A new plugin, a chat widget, a tracking script, an unoptimised hero image or a theme update can each add a little weight. Over months, a site that was once quick becomes slow, and conversion rates drift down without anyone noticing why.
Website optimisation reverses that. It improves the experience for real visitors, supports search visibility through better page experience, makes advertising more efficient because more paid clicks turn into customers, and often reduces hosting and maintenance headaches as well.
Signs your website needs optimising
- Pages take several seconds to show meaningful content on mobile.
- Search Console reports poor or "needs improvement" Core Web Vitals.
- Layouts shift as images, fonts or banners load.
- Buttons and menus feel slow to respond.
- Your site has accumulated plugins, scripts and widgets over the years.
- Paid campaigns have high bounce rates on landing pages.
Who we help
- E-commerce stores, where speed directly affects add-to-cart and checkout.
- Lead generation websites relying on landing page conversion.
- Content-heavy sites with many images, embeds and ads.
- WordPress sites slowed by themes and plugins.
- Shopify stores weighed down by apps.
- Custom and headless builds with heavy JavaScript.
Website optimisation is part of our web development services and supports our technical SEO and CRO work.
Core Web Vitals, explained
Google's Core Web Vitals measure three aspects of real-user experience. They're reported from real visitors' data in tools such as Search Console and PageSpeed Insights.
| Metric | What it measures | Good threshold | Common causes of poor scores |
|---|---|---|---|
| Largest Contentful Paint (LCP) | How quickly the main content appears | 2.5 seconds or less | Large hero images, slow server response, render-blocking CSS and JavaScript |
| Interaction to Next Paint (INP) | How quickly the page responds to clicks, taps and typing | 200 milliseconds or less | Heavy JavaScript, third-party scripts, long tasks on the main thread |
| Cumulative Layout Shift (CLS) | How much the layout jumps unexpectedly | 0.1 or less | Images without dimensions, late-loading banners and ads, web font swaps |
Google assesses these at the 75th percentile of real page loads, so a page passes only if most visitors, not just those on fast devices, get a good experience. Lab tools such as Lighthouse are useful for diagnosing problems, but real-user data is what counts.
What we optimise
We fix causes at the template and platform level, so improvements apply across your whole site rather than one page at a time.
Images and media
Modern formats, correct sizing, responsive images, compression and lazy loading below the fold.
JavaScript
Removing unused code, deferring non-critical scripts and breaking up long tasks.
Third-party scripts
Auditing tags, widgets and trackers, then removing, delaying or replacing the costly ones.
CSS and fonts
Critical CSS, removing unused styles, efficient font loading and fallbacks.
Server and hosting
Response times, caching, compression, HTTP/2 or HTTP/3 and CDN configuration.
Caching
Browser, page and object caching configured correctly for your platform.
Layout stability
Reserved space for images, embeds and banners to prevent shifts.
Plugins and apps
Reviewing WordPress plugins and Shopify apps for weight and conflicts.
Mobile experience
Tap targets, readable text, menus and forms that work well on phones.
Accessibility
Colour contrast, keyboard navigation, labels and headings that help every visitor.
Database and backend
Slow queries, bloated tables and scheduled tasks on dynamic sites.
Monitoring
Real-user and synthetic monitoring with alerts for regressions.
Platform-specific optimisation
WordPress sites are often slowed by heavy page builders, too many plugins and unoptimised hosting. We review every plugin, replace heavy ones with lighter options or custom code, configure caching properly and make sure the theme only loads what each page needs.
Shopify stores commonly slow down as apps are added, each injecting its own scripts. We audit installed and previously uninstalled apps (which can leave code behind), optimise theme code, images and fonts, and prioritise the scripts that matter for sales.
Custom and headless sites built on JavaScript frameworks can be very fast, or very slow, depending on how they render. We review rendering strategy, code splitting, bundle size and data fetching, working closely with your developers.
Whatever the platform, we optimise the templates that matter most first: typically the homepage, key landing pages, category or service pages, product pages and checkout or enquiry forms, because that is where speed has the greatest effect on revenue.
Performance budgets
To stop sites slowing down again, we agree simple performance budgets, such as maximum page weight, script size and Core Web Vitals targets, and check new features against them before they go live.
Budgets turn performance from a one-off project into a shared rule. When a new plugin, tracking tool or design element would push a key page over budget, the team discusses the trade-off before launch, rather than discovering months later that conversions have quietly fallen. We document the budgets, add automated checks where your workflow allows, and review them each quarter as your site and priorities change.
Third-party scripts: the hidden cost
On many marketing websites, the biggest performance problem isn't the site's own code. It's everything added on top: analytics and advertising tags, heatmaps, chat widgets, review badges, social embeds, A/B testing tools, cookie banners and personalisation scripts. Each one downloads code, often from another server, and competes with your page for the visitor's device.
These scripts usually arrive one at a time, added by different people for good reasons, and are rarely removed when they're no longer needed. We start by listing every third-party script, who owns it, what it's used for and what it costs in loading and responsiveness.
Then we decide together: remove tools nobody uses, load non-essential ones later or only on the pages that need them, move tags into a well-governed tag manager, and replace heavy embeds, such as video players, with lightweight previews that load the full player only when clicked.
Common optimisation mistakes
- Chasing a perfect lab score instead of real-user results
- Installing a speed plugin on top of the underlying problems
- Lazy-loading the main hero image, which delays it
- Compressing images but still serving them far too large
- Optimising the homepage while key landing pages stay slow
- Fixing speed once, with nothing to stop it slipping back
Business benefits of website optimisation
Faster, smoother sites help every channel that sends people to them.
- Higher conversion rates, because fewer visitors give up before acting.
- Better use of ad spend, as more paid clicks reach a usable page.
- Stronger page experience signals supporting search visibility.
- Better experience for mobile visitors on slower connections.
- A healthier, easier-to-maintain website with less technical clutter.
Why choose MarquixAd for website optimisation?
Expertise
Developers who understand both performance engineering and marketing.
Strategy
Fixes prioritised by their effect on conversions and key pages.
Technology
Real-user data, lab tools and code profiling used together.
Data
Decisions based on field data, not a single lab score.
Execution
Changes implemented and tested properly, not just recommended.
Optimisation
Continuous monitoring to catch regressions early.
Reporting
Before-and-after reporting in plain language.
Communication
Close collaboration with your marketing and development teams.
Scalability
Approaches that work for small sites and large platforms alike.
Our website optimisation process
We measure first, fix the biggest causes, then protect the gains.
Measure
Real-user data, lab tests and conversion data for key templates.
Diagnose
Identify root causes: images, scripts, server, fonts, layout or code.
Prioritise
Rank fixes by impact on key pages and effort.
Fix
Implement on staging, test thoroughly, then deploy.
Verify
Confirm lab improvements, then real-user improvements over following weeks.
Protect
Agree performance budgets and set up monitoring.
Maintain
Ongoing checks as new features, content and tools are added.
What you receive
Clear before-and-after evidence and a site that stays fast.
| Stage | Deliverables |
|---|---|
| Audit | Performance report by template, with root causes, priorities and expected impact |
| Implementation | Fixes applied and tested on staging, then deployed |
| Verification | Before-and-after lab results and real-user data once available |
| Ongoing (optional) | Monthly monitoring, alerts, performance budget checks and maintenance |
Relevant project experience
Selected optimisation projects will appear here, showing the platform, fixes and verified changes in Core Web Vitals, conversion rate and revenue.
Website optimisation: frequently asked questions
Want to know how fast your site really is? Request a free review.
What is website optimisation?
Improving how quickly and smoothly your website loads and responds, and how easy it is to use, through changes to images, code, scripts, hosting and design.
Why is my website slow?
Common causes include large images, too many scripts and plugins, slow hosting, heavy themes, render-blocking code and third-party widgets. Most slow sites have several causes at once.
Does site speed affect SEO?
Page experience, including Core Web Vitals, is one of many ranking signals. Relevance matters more, but speed strongly affects user behaviour and conversions, so it's worth improving regardless.
What is a good PageSpeed Insights score?
The lab score is a useful diagnostic, but real-user Core Web Vitals matter more. A page can score modestly in the lab and still pass on real users, or the reverse.
How long does optimisation take?
Many improvements can be made within a few weeks. Real-user Core Web Vitals data in Google's reports updates over a rolling 28-day window, so confirmed field results take a little longer.
Will optimisation break anything?
We test all changes on a staging site first, check key journeys such as forms and checkout, and deploy carefully with rollback plans.
Can you speed up a Shopify store?
Yes. We optimise theme code, images and fonts, audit apps and leftover code, and reduce the impact of third-party scripts.
Can you optimise a WordPress site?
Yes. We review themes, plugins, hosting and caching, and replace heavy components with lighter alternatives where needed.
Do we need better hosting?
Sometimes. Slow server response is a common cause of poor loading times. We test before recommending any change and explain the expected benefit.
Do you improve accessibility too?
Yes. We fix common accessibility issues such as contrast, labels, headings and keyboard navigation, which improve the experience for every visitor.
How do we keep the site fast afterwards?
With performance budgets, monitoring and alerts, and a review process for new plugins, apps, scripts and features.
Is this different from CRO?
Yes, though they're closely related. Website optimisation focuses on speed, stability and usability. CRO tests changes to messaging, design and journeys to increase conversions.
Stop losing visitors to a slow website
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