If you are searching for how to 'speed up HubSpot website', you are not alone. A slow website costs conversions, frustrates potential customers, and can harm your search engine rankings. While the HubSpot CMS provides a fast and reliable foundation, the themes, apps, images, and custom code added to your portal are what typically cause performance degradation over time. A fast website is not a luxury; it is a core requirement for any serious business.
This guide provides a systematic, actionable process for diagnosing and fixing the bottlenecks that are slowing down your HubSpot site. We will go beyond simply running a Google PageSpeed Insights report and show you how to analyze what is actually happening when a user loads your page. The process covers the most common and impactful areas: image optimization, script management, CSS delivery, and leveraging HubSpot’s built-in performance features.
Some of these steps can be implemented by a technically-inclined marketer, while others may require developer assistance. The goal is to provide a clear framework you can use to make meaningful improvements. At HubStack, a core part of our HubSpot technical SEO service is a deep performance audit, and this guide walks you through the same principles we apply to client websites to ensure they are fast, responsive, and ready to convert.
Diagnose First: Tools to Accurately Measure Speed
Before you can fix a speed problem, you must accurately measure it. While Google PageSpeed Insights is a good starting point, it only provides 'lab data'—a simulated test from a single location. It is important to understand its key metrics, the Core Web Vitals: Largest Contentful Paint (LCP) measures loading performance, Interaction to Next Paint (INP) measures interactivity, and Cumulative Layout Shift (CLS) measures visual stability. Good scores here are important for SEO, but they do not tell the whole story.
For a deeper analysis, use a tool like GTmetrix, which provides a 'waterfall chart'. This chart visualizes every single file that your browser has to download to render the page, in order. By analyzing the waterfall, you can immediately spot large files (like unoptimized images) or external scripts that are taking a long time to load and blocking other resources. You can also use the built-in Network and Performance tabs in Google Chrome’s Developer Tools to get similar data from your own browser.
Finally, understand the difference between lab data and field data. Field data, which Google collects via the Chrome User Experience (CrUX) Report, shows how real users are experiencing your site. A site can have good lab scores but poor field data if users are on slower networks or devices. Consistent monitoring is key, which is why ongoing HubSpot support and maintenance should always include performance checks.
Image Optimization: The Biggest and Easiest Win
In our experience, oversized images are the single most common cause of slow websites. Optimizing your images provides the most significant performance improvement for the least amount of effort. Image optimization involves three components: resizing, compression, and using the right format. Never upload a 5MB, 4000-pixel-wide photo for a space on your site that is only 600 pixels wide. You must resize images to their display dimensions before uploading them to the HubSpot File Manager.
HubSpot helps by automatically converting your uploaded images (like PNG or JPG) to a modern, efficient format like WebP for supported browsers. This significantly reduces file size without losing visual quality. However, this automatic conversion is only effective if the original uploaded file is reasonably sized to begin with. You can check if WebP images are being served by using your browser's developer tools, inspecting an image, and checking the 'src' attribute or network tab.
Lazy loading is another critical technique. This instructs the browser to only load images when they are about to enter the viewport (i.e., as the user scrolls down the page). Most modern HubSpot themes built by competent developers will include this by default using the `loading="lazy"` attribute on image tags. You can right-click any image on your site and 'Inspect' it to see if this attribute is present. If it is not, your site is wasting bandwidth loading images users may never see.
Managing Scripts: The Root of Most Slowness
After images, third-party JavaScript is the next biggest performance killer. Every external script you add for analytics, heatmaps, chatbots, ad tracking, or other enhancements adds a performance cost. Each script requires the browser to make a new network request to an external server, which introduces latency. Furthermore, the execution of this JavaScript on the page can block the browser's main thread, making the site feel sluggish and unresponsive.
Conduct a script audit. Look in your portal settings under Website > Pages > Integrations > Head and Footer HTML. Make a list of every script tag. For each one, ask: Is this tool still actively used? Does the value it provides outweigh the performance cost? A heatmap script from a test you ran six months ago has no business slowing down your site today. Be ruthless and remove anything that is not essential.
For the scripts that are essential, ensure they are loaded efficiently. Use the `defer` attribute on your script tags (e.g., `<script src="..." defer></script>`). The `defer` attribute tells the browser to download the script in the background without blocking page rendering and to execute it only after the main HTML document has been fully parsed. This is almost always preferable to `async`, which can interrupt rendering. Implementing this correctly might require a developer from a service like our HubSpot website design and development team.
Optimizing CSS: Reduce Render-Blocking Resources
Your website's Cascading Style Sheets (CSS) files are considered 'render-blocking resources'. The browser must download and parse all CSS before it can paint any pixels on the screen. While HubSpot's CMS automatically combines your theme's CSS files into fewer requests, a bloated theme with years of accumulated code can still result in a massive CSS file that slows down the initial render.
An advanced but highly effective technique is the implementation of 'Critical CSS'. This involves identifying the absolute minimum CSS required to style the content that appears 'above the fold' (the visible part of the page on load). This small block of critical CSS is placed directly in the `<head>` of the HTML, allowing the page to render almost instantly. The rest of the larger CSS file is then loaded non-blockingly, similar to a deferred script.
A more practical first step is to conduct an audit to remove unused CSS. As a website evolves, styles for old, deleted modules or components often remain in the stylesheet. Tools within Chrome DevTools can help identify unused CSS rules on a given page. Cleaning this up requires technical expertise and careful testing, but it can significantly reduce the size of your CSS files and speed up rendering. This is a standard procedure HubStack follows during a HubSpot website migration to ensure a clean, fast start on the new site.
Leverage HubSpot's Caching and CDN
HubSpot has powerful, built-in performance features that you benefit from automatically. The most important is its global Content Delivery Network (CDN). The CDN stores copies of your site's static assets—like images, CSS, and JavaScript files—on servers located all around the world. When a user visits your site, these assets are served from the server closest to them, drastically reducing latency and load times.
For dynamic content, such as pages built with HubDB, HubSpot employs server-side caching. When a page is requested, HubSpot generates the HTML and then caches that result for a short period. Subsequent visitors requesting the same page will be served the fast, cached version instead of waiting for the server to regenerate it. You can see the cache status by inspecting the page's response headers in your browser's developer tools and looking for the `x-hubspot-cache-status` header.
HubSpot also sets appropriate browser caching headers, which tell a visitor's browser to store assets locally for a period. This means that on subsequent visits to your site, the browser can load files from its local cache instead of re-downloading them, making navigation between pages feel instantaneous. The main takeaway for marketers is to remember that these caches exist. If you publish a change and do not see it live, you may need to clear your portal's cache or your own browser cache.
| Script Type | Example | Typical Performance Impact | Recommendation |
|---|---|---|---|
| Analytics | Google Analytics (gtag.js) | Low to Medium | Essential for most. Load with `defer`. |
| Tag Managers | Google Tag Manager | Medium | Can become very high if overloaded with tags. Audit tags regularly. |
| Heatmaps/Recordings | Hotjar, Clarity | High | Use only when actively running a test. Disable otherwise. |
| Chatbots | HubSpot Chat, Drift, Intercom | High | Load conditionally or after a delay if possible. Evaluate its ROI against performance cost. |
| Video Players | YouTube, Vimeo embeds | High | Use a facade/thumbnail that loads the player on click instead of a direct embed. |
| Ad Pixels | Meta Pixel, LinkedIn Insight Tag | Medium | Load with `defer`. Essential for ad tracking but monitor performance. |
When You Need a Professional Technical Audit
If you have implemented the low-hanging fruit—optimizing images, removing unused scripts—and your site still fails to meet performance targets, the problem likely lies deeper within your theme's architecture or code. This is the point where a professional technical audit becomes necessary. Slow HubL queries, inefficiently structured CSS, or excessive JavaScript execution can create bottlenecks that are not obvious from a simple waterfall chart.
A professional HubSpot technical SEO audit goes beyond surface-level checks. It involves profiling the browser's rendering process to see what tasks are taking up the most time, analyzing JavaScript execution with tools like the Chrome DevTools Performance tab, and manually reviewing theme HubL code for inefficiencies. This process, which we perform at HubStack for our clients, pinpoints the exact root causes of slowness.
The outcome of a technical audit is not just a report; it is a prioritized roadmap of actionable fixes. Each recommendation is weighed by its potential performance impact versus the effort required to implement it. Investing in a professional audit is an investment in user experience, lead generation, and brand perception. It is the most reliable way to turn a slow, frustrating website into a fast, high-performing asset. Check our pricing to see how we can help.