Site Speed and Headless CMS

When it comes to the benefits of migrating to a Headless CMS, performance is often cited as a primary driver. This short article outlines why this is such a crucial issue and explores how a Headless CMS delivers enhanced performance.

Alan Gleeson - CMO Contento

Alan Gleeson

Co-Founder / CEO

February 15, 2023

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7min read

Tuk Tuk driving really fast

Context - Fast Website Speed and SaaS Scaleups

When it comes to the benefits of migrating to a Headless CMS [What is a Headless CMS?], performance is often cited as a primary driver. This short article outlines why a fast website speed is such a crucial issue and explores how a Headless CMS delivers enhanced performance.

First some context. There are an estimated 2 billion websites on the internet. This article is intended for those working in a tiny subset of these: technology/ B2B SaaS companies that are either scaling up or are aspiring to scale up.


When it comes to managing websites, opinions as to how best to do so are everywhere. Like this blog, those sitting in different camps profess how their offering is best. What works well in one context may not work well in another. 

WordPress, is the most popular Content Management System (CMS) worldwide, and has a significant ecosystem alongside the huge number of installs it has enjoyed over its almost 20 year history. With many web developers working with it, it will continue to have strong supporters advocating for it. 

While it remains a solid choice of CMS for many use cases, as this blog argues, for a certain cohort; growing technology companies including B2B SaaS scaleups, WordPress issues and drawbacks negatively impact performance. Chief amongst them is site performance, or specifically site speed. Compared to other CMSs WordPress can fall badly short when it comes to speed tests. 

Why WordPress Is Not Great for Fast Website Speeds?

There are several reasons for this:

  1. The way WordPress is built [template based all-in-one system]

  2. The number of plug-ins that tend to be installed

  3. 3rd party software in place (added to over the years)

One challenge with B2B SaaS scaleups is that over the lifecycle of their business the tenure of marketing leaders is typically very short. A consequence of that is different marketing leaders testing various marketing technology solutions, without removing them when they depart. Over time website bloat becomes an issue as a result of the activities of the different Chief Marketing Officers over the years.

Why Does Speed Matter?

When it comes to scaling B2B SaaS companies we can make some assumptions. 

  • They are past the Product Market Fit (PMF) phase so have traction

  • In most, if not all cases, their market will be global

  • Site traffic will have grown and will be significant

  • Primary goals on the site will relate to conversions

  • SEO will be important as you look to increase inbounds while keeping your Cost of Acquisition down (CAC)

When you consider these factors the importance of optimizing for a fast website site speed becomes a key factor when looking to drive better conversion rates. Hence the following are all correlated to speed:

  • Conversion Rates (Bounce rates increase on slow sites)

  • User Experience (Who likes a slow site?)

  • SEO Performance (speed is a ranking factor)

It is worth noting at this juncture that there is a nuance here that many B2B SaaS companies are unaware of. You may be based in an office in London, and think that your own website is loading quickly. The real test is what the speed looks like in your core markets (often the US). The differential can be material and thus the fast experience you enjoy at your desk may be completely unrepresentative of the experience of your core targets.

In short, speed is a silent killer. It is usually not obvious unless you are looking out for it. However, for a certain cohort - scaling technology companies, performance optimization is of vital importance.

Measuring WebSite Speed

A useful first step is to run some speed tests on the site. Ideally, they are focused on the home page and other high-dollar value pages (i.e. pages like landing pages, the pricing page, etc where conversions typically come from). 

There are several free tools you can use to run the tests and to measure your site speed: 

  • Pingdom (solarwinds)

  • GTmetrix

  • Google [PageSpeed Insights]

  • WebPage Test by catchpoint

However, there are a few things to be aware of.

  1. It is not about ‘the score’. The way these tools are set up it is not realistic to be achieving a perfect score. It is about identifying problem areas.

  2. Some of these sites break the scores down between Mobile and Desktop speeds. In most instances, the performance measurement on mobile devices tends to be worse than desktop speeds. Given the nature of B2B SaaS where many applications rely on desk-based input to produce/create/manage rather than to consume, I tend to focus more on desktop scores.

  3. The results can be hard to interpret without some technical input. The reports issued tend to be quite detailed and include references like “Time to First Byte” and “Largest Contentful Paint”. What are you really looking for are red flags related to overall page performance?

  4. Scores can vary and can jump around, so it may be worth running tests over a few days (at different times).

What Website Speed Should you be Looking For?

So how do you know how your site is performing?

Firstly, start with 3 seconds, and then look to get it to under 1 second. Ideally you also ‘pass’ the Google PageSpeed Insights test. 

The probability of bounce increases 32% as page load time goes from 1 second to 3 seconds.

—Source: Google/SOASTA Research, 2017.

As page load times goes from:

1s to 3s the probability of bounce increases 32%

1s to 5s the probability of bounce increases 90%

1s to 6s the probability of bounce increases 106%

1s to 10s the probability of bounce increases 123%

— Source: Google/SOASTA Research, 2017.

Based on your score you can then assess what action you need to take.

The factors that impact speed are numerous and can include the following:

  • Choice of CMS

  • Image compression (or lack thereof)

  • Use of 3rd party plug-ins

  • Other 3rd party software running (often Marketing Technologies)

Images and JavaScript are the most significant contributors to the page weight that affect page load time based on data from HTTP Archive and the Chrome User Experience Report - our public dataset for key UX metrics as experienced by Chrome users under real-world conditions.

— Source: Addy Osmani, Senior Staff Engineering Manager, Chrome

However, the choice of CMS is the most significant determinant as to whether or not you have the correct infrastructure in place to ensure success. It is thus the area to address if your scores are higher than an acceptable level (ideally less than 2 seconds whether testing on UK or US servers).

Traditional CMS v Headless CMS

In recent years, Headless CMS has emerged as an alternative approach to building and managing websites. Unlike the traditional approach, with a Headless CMS, the front-end and the back-end are decoupled. While this won’t suit many website owners, it is usually not an issue for growing technology companies. Instead they will enjoy the additional benefits Headless brings, with performance and security being two of the key ones.

Recommended Resource: What are the Key Benefits of a Headless CMS?

WordPress sites can struggle to scale and over the years, performance can degrade as mentioned above. Even when setup optimally, the architecture won’t match that of a Headless CMS. With a Headless CMS, like Contento, the reliance on Content Delivery Networks (CDNs) married to the API-first approach means that structurally Headless CMSs perform a lot better. They are simply way faster.  

CMS and Fast Wesbite Speed Research

In a recent study that we conducted assessing the Content Management Systems (CMS) of the Top 25 B2B SaaS Websites in Ireland (2023) we found significant performance differences between the two approaches with those sites using a Headless CMS running much more quickly than those on WordPress or an equivalent. 

The cohort on WordPress had an average site speed (US) of 2.49 seconds, whereas the average for those on a Headless CMS was a mere 1.1 seconds.


In summary, when it comes to fast-growing technology companies (especially B2B SaaS scaleups) site speed becomes an increasingly important area to focus on. The choice of CMS is the major factor in whether the site is performing well or not. Headless CMS sites outperform Traditional CMSs like WordPress without compromising on design or security. 

Is it any wonder that major tech companies like Stripe, Intercom, Miro, and Teamwork have already made the leap to Headless?

Please note ChatGPT was not used in the production of this blog.

Alan Gleeson - CMO Contento
Alan Gleeson

Co-Founder / CEO

Alan Gleeson has 15+ years extensive B2B SaaS experience working with several VC backed Startups & Scaleups in the UK, US & Ireland.

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