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What is a headless CMS?

Everything marketers and developers need to know about headless, decoupled, and API-first content management systems

Chapter 1

What is a headless CMS? (the short version)

Headless CMS architecture separates back-end content functions (like creation, management, and storage) from front-end functions (like presentation and delivery).

OK, but really: What is a headless CMS?

So what does that actually mean? Why is headless architecture important to the future of digital experiences?

Headless architecture is partly a response to the way web content has evolved. For a long time, most web content was delivered through a browser, often as a web page. But new connected devices are arriving all the time.

Today, audiences consume content through new interfaces with different form factors—things like smartphones, wearables, AI-enabled voice assistants, and even virtual reality headsets.


Headless CMS architecture is foundational to addressing these new content challenges. It means you can easily create and manage more things and deliver them to more places.

But before we get too technical, let’s start with the basics.

Here’s an overview of two fundamental architecture decisions and how they impact how content is created, stored, managed, delivered, and even personalized.

How does CMS architecture impact how content exists on a page?

Find out the difference between page-based vs. object based architecture, and why your AI-enabled voice assistant isn't nearly as smart as it sounds.


How does CMS architecture impact how (and where) content is presented to the audience?

Discover the differences between headless vs. non-headless architecture, and find out how to avoid the personalization and analytics trade-off headless usually comes with.


Chapter 2

CMS architecture 101

CMS front end vs. back end

Traditional CMSs have two halves: one front and one back.

Broadly speaking, the back end of a CMS relates to how content is managed, and the front end relates to how it’s presented. Think of it like a storefront window display.

Front-end tasks include everything you’d see as you peered in from the street: the selection and arrangement of products and accompanying signage.

Back-end tasks include logistics—making the signage, storing the inventory, and managing the movement of goods around the store.

So, for a basic website, the back end might include:

  • A simple interface to create content
  • A database to store digital assets
  • An application layer to create and apply design frameworks

The front end would then pull through content, stored assets and designs, and publish them to an HTML page.

What is a decoupled CMS?

Traditionally, the CMS front end and back end were tightly locked together. Users could create, store, manage, and publish content all within a single interface.

For non-technical users publishing simple content—like a blog—this was a great, seamless setup.

But as digital experiences evolve, developers are spending too much time creating custom workarounds to deliver more sophisticated content to a wider variety of devices.

Decoupled CMSs split back-end and front-end tasks. In practice, this means developers can quickly code and design front-end experiences in their preferred language without being bound by restrictive back-end technologies. Instead, they can use Application Programming Interfaces (APIs) to connect the back-end functions—like content storage and management—to any front-end delivery environment


What is an API-first CMS?

Where decoupled CMSs separate back-end and front-end functions, they often still include some front-end delivery tools, such as page templates or module integrations.

API-first CMSs are functionally the same as headless CMSs in that they have no default front end. Developers are free to create as many delivery layers as needed, (in whatever language they prefer) to push content to any new channel imaginable.

API-first CMSs are great if you have a team of skilled developers ready to go—the CMS simply manages content and waits for an API call from a front-end delivery layer built by the development team.

Decoupled CMSs, on the other hand, suit companies who want the flexibility of a separate front end and back end, but who might still need some publishing support.

Chapter 3

What (and who?) is a headless CMS useful for?

Headless CMSs are undoubtedly the future of content management, for two important reasons.

First, digital content is getting more sophisticated, and users’ expectations are rising. To stand out, you need to build beautiful, responsive, and interactive content—and you need to be able to do it quickly.

Second, new channels and user devices are emerging all the time. It’s not enough to build beautiful stuff—you also need to make sure you can deliver it everywhere, as efficiently as possible. Headless CMSs mean marketers and developers can build amazing content today, and—importantly—future-proof their content operation to deliver consistently great content everywhere.


It's great for marketers, developers, and users.

It’s great for marketers because…

…they can create content once while enabling their developers to display it anywhere. That means less time spent on administration and more time for building beautiful, cohesive experiences.

It’s great for users because…

…the user experience always feels fast, consistent, and responsive. That’s because the client side doesn’t need to communicate with the back-end system—it just has to render content.

It’s great for developers because…

…they’re released from the back-end restrictions of programming languages where they lack expertise. Instead, they can build the look, feel, and functionality of user experiences using tools they know and like (e.g. JavaScript libraries and frameworks), and then push content out anywhere using the latest APIs.

Chapter 4

What are the drawbacks of a headless CMS?

Off-the-shelf headless CMSs aren't a magic bullet to fix all your content challenges. They can come with two major trade-offs that need to be seriously considered.

For one, what you gain in flexibility, you lose in accessibility. Since presentation is left to developers writing JavaScript, non-technical marketers can’t use What You See Is What You Get (WYSIWYG) authoring or editing.

The second one is bigger.

Something drastic happens when you cut the head off a CMS: you sever the ability to send customer interaction data between the front end and the back end in real time.

That means you can’t personalize experiences or run content analytics activities.

Personalization has gone from a “nice-to-have” to a table-stakes requirement. Customers are learning what great personalization feels like from industry leaders like Amazon, Netflix, Spotify, and others.

If you can’t provide a similar experience, customers will likely go elsewhere—and soon. So what’s the answer?

Chapter 5

Enter the hybrid-headless cms

The ideal CMS architecture would combine the flexibility and extensibility of a headless CMS, with the personalization and content analytics capabilities offered by traditional coupled CMS.

That’s exactly what Sitecore's headless delivery options provide.

Multiple headless options support front-end developers as they build solutions and apps that render content on any device or browser. Whether using JavaScript libraries such as Vue.js, React.js, and Angular.js, or leveraging the new ASP.NET Core SDK and headless rendering host architecture, developers can choose what's best for them.

These options also come with an API that connects to Sitecore’s contextual content delivery server. This uses information from Sitecore’s Experience Database™ to support devices and browsers to interpret both content and personalization rules in real time. So users see different content based on profile information, past interactions, and more.

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