The ultimate A-Z guide to headless CMS terminology

By Arso Stojović
Read time 23 min
Posted on June 9, 2023
Updated on August 24, 2023
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Headless CMS terminology

Headless CMS is gaining popularity due to developers wanting more freedom and the rise of omnichannel delivery and rich front-end frameworks. By using this comprehensive headless CMS glossary, everyone involved in the development process will understand what headless CMS is. In addition, everyone will learn how it helps businesses grow.

Everybody, from founders, makers, product people, and marketers — with or without a technical background - will finally understand vague terms such as "API," "HEADLESS CMS," and "JAMSTACK."

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Headless CMS has evolved rapidly in the past decade, opening the door to an ever-increasing array of applications and innovations. The result is a wealth of complex terms, concepts, and technologies. Even for the most technically minded, keeping up with the latest advancements takes time and effort.

This glossary covers essential terminology associated with headless CMS and its many components to facilitate a deeper understanding of the concept.

Each term is explained in two ways:

  • As a boring school definition from textbooks that are hard to learn

  • and with the words that the smartest kid in the class would use to explain to everyone how the whole headless concept makes sense and how simple it is.

Either way, save this headless CMS dictionary in your bookmarks because we're sure you'll find it helpful daily.



Textbook definition: API (Application Programming Interface) represents a set of rules and protocols allowing software applications to communicate. In the context of a headless CMS, APIs enable developers to retrieve and manipulate content stored in the CMS.

Classmate explanation: APIs are like interpreters for computer programs. Just like an interpreter helps people speak different languages and understand each other, APIs help software applications talk to each other and share information. In the case of a headless CMS, the API allows developers to get content from the CMS and change it using their own applications. This includes websites or mobile apps. It's like a special rulebook that helps different programs work together smoothly.

API-first CMS:

Textbook definition: A content management system that prioritizes using APIs for content creation, management, and delivery. It is designed to provide content through APIs, allowing developers to build and customize front-end experiences using CMS content.

Classmate explanation: it's like a content management system that gives developers a VIP pass to access and control all the content. Instead of traditional methods, it focuses on using APIs, which are like secret codes that unlock the content vault. This way, developers can create awesome front-end experiences without CMS headaches. It's like having a backstage pass to the content party!

Atomic deploys:

Textbook definition: A deployment that has either been executed entirely or not executed at all, leaving no trace of the working code on the server. This means that your live website will only be updated once the deployment has finished successfully.

Classmate explanation: Imagine updating your website is like launching a rocket into space. Atomic deploys are like countdowns that either result in a successful liftoff or a scrappy "oops, let's try again." It's all or nothing! The good news is your live website stays safe until deployment is a perfect 10/10. No half-baked changes here!



Textbook definition: The behind-the-scenes part of a software application that deals with data storage, processing, and logic. In a headless CMS, the back-end manages content storage and retrieval.

Classmate explanation: The back-end is like a hidden storage place where all important information is kept in a software application. A headless CMS, it's like a special box that stores articles, pictures, and videos for a website. The back-end organizes and retrieves content when it's needed. It's like a smart system that knows where everything is and can quickly prepare it to be shown on a website or other platforms.


CDN (Content Delivery Network):

Textbook definition: A geographically distributed network of servers that delivers web content to users based on their location. CDNs are often used with headless CMS to optimize content delivery speed and performance.

Classmate explanation: When you want to see a website, CDNs are the cool crew that makes it happen faster than a cheetah on roller skates. They have servers all around the globe, ready to sprint into action. Just like sending a letter to your friend, CDNs pick the server nearest to you and deliver the website's content lightning-fast.


Textbook definition: CLI stands for Command Line Interface, which connects users to a computer program or operating system. Users interact with a system or application by typing commands (text).

Classmate explanation: It's like talking to a computer in its secret language. Instead of fancy buttons and icons, you become a coding wizard and type in commands like a boss. It's the nerdy way to get things done, but hey, it's efficient and makes you feel like a hacker in a spy movie!

Client-side rendering:

Textbook definition:  Client-side rendering (CSR) refers to rendering pages directly in the browser using JavaScript.The client handles all logic, data fetching, templating, and routing instead of the server.

Classmate explanation: It's like talking to a computer in its secret language. Instead of fancy buttons and icons, you become a coding wizard and type in commands like a boss. It's the nerdy way to get things done, but hey, it's efficient and makes you feel like a hacker in a spy movie!

Content management system:

Textbook definition: (CMS) is software that helps users create, manage, and modify content on a website without technical knowledge. In other words, a CMS lets you build a website without writing code from scratch (or even knowing how to code at all).

Classmate explanation: It's like having a cool toolbox full of content for your website. Instead of being stuck with one way to show your content, you can use it anywhere. So, you can put your content on websites, apps, or even robots without being a coding genius. It's like having superhero power to create and manage awesome content without all the technical stuff.

Content Model:

Textbook definition: A representation of content structure and organization within a headless CMS. It defines the types of content, their fields, relationships, and validation rules.

Classmate explanation: Think of it as a blueprint for organizing stuff in a headless CMS, like a virtual Lego world. It helps you decide what things you can make, what info they should have, and how they're connected. It's like a rulebook that keeps everything in order, making sure names aren't too long and colors are spelled right. So, it's your handy guide to creating and organizing awesome digital stuff!


Textbook definition: A specific type or category of content within a headless CMS. Examples include blog posts, product descriptions, or image galleries.

Classmate explanation: It's like different flavors of ice cream in a headless CMS. You have blog posts, product descriptions, image galleries, and more. Each one has its own unique style and purpose, just like different ice cream flavors. So, it's all about categorizing and organizing yummy content in your digital world!


Data source:

Textbook definition: Data sources are locations where data is used in computer science and computer applications. Many data sources can be used in computer programs, including spreadsheets, XML files, and even hard-coded data.

Classmate explanation: It's like a treasure map for your computer. You see, your computer needs data to do cool stuff, like showing pictures or crunching numbers. Data sources are like different places where your computer can find that data. It could be in files, spreadsheets, or even hidden inside special codes. So, think of data sources as secret hiding spots filled with information your computer needs to work its magic!


Textbook definition: A database is a repository of information managed by a database engine that ensures data integrity and fast access to the data.

Classmate explanation: It's like a super organized storage unit for information. Imagine you have a bunch of stuff you need to keep track of, like books, movies, or even your sneaker collection. A database helps you store and manage all that information in a neat and efficient way. It's like having a super-powered librarian who keeps everything in order and makes it easy for you to find what you're looking for.

Decoupled CMS:

Textbook definition: Another term for a headless CMS. It refers to separating the front-end and back-end layers, allowing greater flexibility and reusability of content.

Classmate explanation: Just learn what is the headless CMS; it’s basically the same.


Textbook definition: The process of making a software application or website available for use. In the context of a headless CMS, deployment involves configuring and launching the CMS in a production environment.

Classmate explanation: It's like launching a rocket into space but for software! When a headless CMS is ready to launch, it's time for deployment. It's like pressing the big red button to make the CMS available for everyone to use. Just like a rocket needs careful preparation before taking off, deployment involves configuring and launching the CMS in a real-life environment.


Textbook definition: The term deferred static generation (DFG) refers to a rendering technique in which certain pages are deferred until runtime or until the renderer finds them.

Classmate explanation: It's like having a surprise party but for web pages! Instead of making all the pages ahead of time, DFG waits until someone asks for a specific page, and then it quickly puts it together just in time. This way, you get fresh and up-to-date content without making the website work too hard in advance.


Textbook definition: The Document Object Model (DOM) is an application programming interface (API) for HTML and XML documents. It defines the logical structure of documents and how they are accessed and manipulated.

Classmate explanation: Think of the DOM as a superhero that can see inside web pages and XML documents, like X-ray vision! It organizes the messy jumble of HTML or XML code into a neat structure that programmers can understand and play with. With the DOM, programmers can fetch information, make changes, and even create new elements in the document.


Textbook definition: DPR (Delivered Persistent Rendering) enables developers to defer rendering URLs or assets until requested. If you use DPR, you can prerender critical pages, such as your homepage or recent blog posts, at build time.

Classmate explanation: Imagine you're hosting a party but don't want to set everything up until your guests arrive. With DPR, you can do just that! It's like having party decorations that appear instantly when someone walks through the door. So, instead of prepping everything in advance, you can wait until the last minute to make things look amazing.



Textbook definition: In cyber security, encryption is the process of converting data from a readable format into an encoded one. In general, encryption software uses an algorithm or cipher to create an encryption scheme that can only be broken with a lot of computing power.

Classmate explanation: Picture your secret diary full of embarrassing stories, but instead of hiding it under your mattress, you turn it into an indecipherable code. It's like writing with an invisible ink that only you can reveal with a special decoder. Encryption is a fancy way of making sure your digital messages and files stay safe from prying eyes.


Textbook definition: A specific URL (Uniform Resource Locator) that serves as an entry point to access a particular resource or functionality through an API. Endpoints are used to retrieve or update content in a headless CMS.

Classmate explanation: It's like having a secret doorway to get what you want from a headless CMS, just like a secret code that opens a hidden treasure chest. It's like your VIP pass to the CMS world, where you can retrieve or update content with magical URL tricks. So, use those endpoints wisely and unlock the wonders of a headless CMS!



Classmate explanation: A framework consists of instructions for completing a task. Frameworks allow software that provides generic functionality to be selectively modified by additional user-written code to provide application-specific functionality.

Classmate explanation: A framework is like a recipe book for building software. It gives you a structure and guidelines to follow, so you don't have to reinvent the wheel every time. It's like having a handy toolbox filled with pre-made tools that you can customize and use to build amazing things. With a framework, you can focus on adding unique touches and making your software unique.


Textbook definition: The visible part of a software application or website that users interact with. In the context of a headless CMS, the front-end displays content retrieved from the CMS.

Classmate explanation: It's like the fancy outfit of a software application or website. In the same way, you slayed the fashion show; it's what makes you look cool and stylish. Front-end makes you popular in a school. It's all about making things visually appealing, like wearing a stunning outfit that catches everyone's attention.


Gatsby CMS

Textbook definition: Gatsby CMS is a specialized software solution designed to manage content within Gatsby.js applications. It facilitates tasks such as content creation, editing, structuring, media management, version control, workflow management, and customization. This tool optimizes content management workflows specifically for Gatsby.js projects, enhancing productivity and streamlining content delivery.

Classmate explanation: Imagine you're the master architect of your very own digital kingdom, just like in The Sims game! You've got Gatsby.js as your magical building tool, helping you craft your dream world with all its quirks and wonders. It's like having a virtual assistant who's an expert at organizing everything in your Sims world. With Gatsby CMS, you can easily create new content, rearrange things if you're feeling creative, and even rewind to previous versions if you make a mistake – just like hitting "undo" in The Sims.

Git-based CMS:

Textbook definition: GitHub-based CMSs use Git as their version control system (VCS). In a repository, Git stores your files and their history of changes. In general, it simplifies the management of content-especially text-by enabling you to branch out, merge, clone, react to changes, and in general, branch out, connect, clone, and react to changes.

Classmate explanation: Imagine you're working on a group project, but instead of everyone writing on the same piece of paper, you each have your own copy that you can edit. GitHub-based CMSs use Git, which is like a super smart system that keeps track of all changes you make to your files. It's like having a time machine for your work, so you can go back in time and see how your files evolved. It also lets you work on different versions of your project at the same time without messing things up.


Textbook definition: A query language for APIs that enables clients to efficiently request and retrieve specific data. GraphQL is often used with headless CMSs to fetch content flexibly and efficiently.

Classmate explanation: A fancy language for talking to computers and getting exactly what you want. It's like ordering a pizza and telling the chef exactly what toppings you want without getting any extra stuff you don't need.


Headless CMS:

Textbook definition: A content management system that focuses solely on content creation, storage, and delivery, without dictating how content is presented. It provides content via APIs to be consumed by various front-end applications.

Classmate explanation: It's like having a super cool chef who only makes the finest ingredients for your favorite dishes. A headless CMS is all about creating, storing, and delivering content without telling you how it should look. It's like giving you the tastiest pizza toppings, but you get to decide how to arrange them on the pizza. So, a headless CMS is all about delicious content, giving you the power to serve it up in any dish you want.

Headless CMS



Textbook definition: The process of connecting different software systems to work together seamlessly. Headless CMSs often require integration with other tools or platforms to enhance functionality, such as e-commerce platforms or marketing automation systems.

Classmate explanation: It's like teaming up your favorite superheroes for an epic mission! When different software systems become friends and work together, it's called integration. Just like Iron Man and Captain America joining forces, a headless CMS needs to connect with other tools or platforms to become even more powerful; it's all about teamwork and making the headless CMS even more supercharged!



Textbook definition: A modern web development architecture for JavaScript, APIs, and Markup. It involves building websites or web applications by pre-rendering static files, fetching dynamic data through APIs, and using JavaScript to handle interactivity.

Classmate explanation: Imagine building a special toy castle! You use JavaScript, APIs, and Markup to make it amazing. It's like drawing the castle, adding cool stuff, and making it come alive with buttons and sounds. You're the king or queen of the web!


JSON (JavaScript Object Notation):

Textbook definition:  A lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. JSON is commonly used for transferring data between headless CMS and client applications.

Classmate explanation: It's like a secret code that makes sharing information between headless CMSs and other computer programs easy. JSON helps everyone talk to each other and share data without any confusion.


Knowledge base:

Textbook definition: A centralized repository of information, documentation, and resources related to headless CMS. It is a reference for developers, content authors, and users to access guidance and support.

Classmate explanation: It's like a super smart library filled with all the answers you need about headless CMS. It's a one-stop shop for developers, content creators, and users to find helpful information and tips.



Textbook definition: The process of adapting software or content to specific languages, regions, or cultures.

Classmate explanation: Making software feel at home wherever it goes. It's like giving it a passport to travel the world and fit right in. Imagine a game speaking your language, a website using your local slang, or an app understanding your favorite emoji. It's all about making things feel personal and friendly, no matter where you are.


Markup Language:

Textbook definition: A set of codes or tags that define content structure and presentation. Common examples include HTML (Hypertext Markup Language) and Markdown. Headless CMSs often support multiple markup languages.

Classmate explanation: It's like a secret language for computers to understand how to show things on a screen. Imagine if you had a magic pen that could draw pictures by following special instructions. Markup language is just like that! It uses special codes or tags to tell the computer how to structure and present content. It's like giving the computer a recipe to make a tasty cake. HTML and Markdown are examples of markup languages, like two different recipes for delicious treats.


Textbook definition: A software architectural approach that structures an application as a collection of small, loosely coupled services. Headless CMSs can utilize microservices to enhance scalability and flexibility.

Classmate explanation: Imagine a puzzle where each piece does its own thing but still fits perfectly with the others. That's what microservices are like in software. They break down a big application into smaller, independent services that work together smoothly. Headless CMSs use microservices to make things more flexible and scalable, just like puzzle pieces that can be rearranged easily.


NextJS headless CMS

Textbook definition: NextJS headless CMS is a software platform designed to facilitate content creation, management, and delivery within Next.js applications. It offers intuitive interfaces for content editing, structuring, media management, version control, workflow management, and customization, optimizing content management workflows for Next.js projects.

Classmate explanation: NextJS headless CMS is like having a magical castle where you can effortlessly create, organize, and serve up all your content. With sleek interfaces that even your grandma could navigate, it's a breeze to edit text, swap out images, or add new stuff without breaking a sweat. In short, it's like having a super-smart assistant who takes care of all the content stuff, leaving you free to focus on making your Next.js project as awesome as it can be.


Textbook definition: An open-source JavaScript runtime environment allowing developers to run JavaScript code outside a web browser. Node.js is often used in headless CMS back-end development.

Classmate explanation: It's like a super cool playground for JavaScript. Just like you can play soccer on a field or in your backyard, Node.js lets developers run JavaScript code outside of a web browser. It's like taking JavaScript on an adventure beyond the internet and into the world of servers and back-end development.

Nuxt CMS

Textbook definition: Nuxt CMS is a software tool tailored for managing content within Nuxt.js applications, providing features like content editing, structuring, media management, version control, workflow management, and customization. It streamlines content management workflows specific to Nuxt.js projects, enhancing efficiency in content creation and delivery.

Classmate explanation: Imagine you're building a really awesome LEGO house, but you need cool stuff like LEGO people, trees, and cars to make it super fun. Now, getting all those tiny LEGO pieces in order can be a big job! But guess what? There's a special LEGO box that magically organizes everything for you! It helps you pick the right pieces, keeps track of them, and even fixes mistakes if you put a piece in the wrong spot. So, instead of spending forever sorting through your LEGO pile, you can focus on building the coolest LEGO house ever!


Open source:

Textbook definition: Freely available software that can be modified, enhanced, and distributed by the community. Some headless CMSs are open-source, allowing developers to contribute and customize their development according to their needs.

Classmate explanation: Think of it as a giant Lego set that comes with instructions but also allows you to build and modify it however you want. Open-source software is like those Legos that anyone can use, change, and even share with others. Some headless CMSs are like special sets of Legos that developers can use to create amazing websites or apps, and they can even add their own unique pieces to make it truly their own.


Preview Mode:

Textbook definition:  A feature of a headless CMS that allows content authors and editors to preview how content will look before publishing it. This helps ensure that the content appears as intended on different devices or platforms.

Classmate explanation: It's like having a superpower to peek into the future! With preview mode, content authors and editors can see how their work will look before going live. It's like trying on different outfits and checking yourself out in the mirror before going to a big event.



Textbook definition: In headless CMSs, a query is a request for specific data from the CMS. Developers use queries to retrieve content based on specific criteria, such as filtering by category or sorting by date.

Classmate explanation: It's like being a detective and asking the CMS for exactly what you need. Instead of searching the entire CMS for information, you can use queries to tell it, "Hey, I only want articles about cats" or "Show me the newest photos." It's like having a secret code that lets you fetch the exact data you want, saving you time and effort. Just like a detective, you can interrogate the CMS and get the answers you need.


Real-time collaboration:

Textbook definition: The ability for multiple users to work on the same content simultaneously, seeing each other's changes in real-time. Some headless CMSs provide collaborative editing features to enhance team productivity.

Classmate explanation: It's like having a super cool party where everyone works on the same project at the same time. With collaborative editing, you and your teammates can all work together on the content and see each other's changes in real-time. So, collaborative editing is like throwing an awesome content party where everyone can join in and make the project amazing. It's all about teamwork, creativity, and getting things done in a super fun way!

REST (Representational State Transfer):

Textbook definition:  A software architectural style that provides a set of principles for building web services. RESTful APIs are commonly used in headless CMSs to enable conditions on how an API should work.

Classmate explanation: The rulebook for web services to play nicely together. It sets standards for how apps communicate and behave, like a referee or a traffic cop. It keeps everything organized and prevents chaos on the internet playground.



Textbook definition: The ability of a software application or system to handle increasing amounts of data, traffic, or users. Headless CMSs are designed to be highly scalable, allowing organizations to manage growing amounts of content.

Classmate explanation: Think of scalability as having a magic backpack and being able to handle more and more without getting overwhelmed. It's like having a superpower that lets you keep up with anything that comes your way. So, with a scalable headless CMS, you're ready to take on the world of content, no matter how big it gets!


Textbook definition: Software development kits are collections of software development tools in one installable package. They facilitate application creation with a compiler, debugger, and software framework.

Classmate explanation: It's like a toolbox for developers. Instead of searching for tools all over, the SDK gives you everything you need in one package. It's like having a kit with a compiler to build your code, a debugger to fix mistakes, and even a framework to make things easier. It's like having all the cool gadgets you need to create amazing software.

Server-side rendering:

Textbook definition: Server-side rendering (SSR) is an application's ability to convert HTML files on the server into a fully rendered HTML page for the client. The web browser submits a request for information to the server, which instantly responds by sending a fully rendered page to the client.

Classmate explanation: It's like having a personal chef who prepares your food before serving it to you. When you request a webpage, the server does all the hard work of putting it together and then serves you the finished dish.


Textbook definition: Serverless is a cloud-native development model that allows developers to build and run applications without managing servers.

Classmate explanation: It's like renting a fancy restaurant instead of building your own kitchen. You don't have to worry about buying ingredients, cooking, or cleaning up afterward. You just show up, enjoy the delicious food, and leave the rest to the restaurant. In the same way, serverless developers can focus on writing code and creating amazing applications without managing servers.

Single-page Application (SPA):

Textbook definition: A web application that loads a single HTML page and dynamically updates its content as users interact with it. Headless CMSs are often used with SPAs to fetch content on demand.

Classmate explanation: So, a single-page application is like a book that changes its pages as you read, and a headless CMS is like a helpful genie that brings you the right content whenever you want it. It's all about making your web experience magical and exciting!

Static site generator:

Textbook definition: A static site generator generates a fully interactive HTML website based on raw data and templates. A static site generator automates the task of coding individual HTML pages and getting those pages ready to serve users ahead of time.

Classmate explanation: It's like having a magic machine that takes your ideas, sprinkles them with code, and poofs! It spits out a ready-to-use website. No need to handcraft every page. Just feed it some data and templates, and voila! It generates a fully functional website that's fast, efficient, and ready to impress. It's like having a website-making genie in a box!



Textbook definition: The process of creating reusable templates or layouts for content presentation. In headless CMSs, templates are typically designed separately from the content and are responsible for fetching and rendering the content.

Classmate explanation: It's like having a cool recipe that helps you make awesome cupcakes every time. In the world of headless CMSs, templating is all about creating reusable templates or layouts for how your content looks. The templates are like the master chefs who know exactly how to bring your content to life. They fetch the right ingredients (content) and put them together in a delicious way, making everything look amazing.


User Authentication:

Textbook definition: The process of verifying the identity of users accessing a software application or system.

Classmate explanation: The bouncer at the virtual door who asks, "Who goes there?" before letting you in. It ensures that only authorized individuals can access a software application or system by verifying their identity. So no sneaky intruders allowed!



Textbook definition: The practice of keeping track of changes to software or content over time.

Classmate explanation: The history buff of the software world. It keeps a detailed record of every change made to software or content, like a time-traveling diary. So you'll never lose track of what's been added, removed, or fixed, making it easier to collaborate and go back in time if things go haywire.



Textbook definition: A mechanism that allows real-time communication between different software applications by sending notifications when specific events occur.

Classmate explanation: The messenger pigeons of the software world. They fly back and forth between different applications, delivering important news in real-time. When something interesting happens, like a new order or a comment on your blog, webhooks swoop in to let other apps know so everyone stays up to date without lifting a finger.



Textbook definition: (eXtensible Markup Language): A markup language that defines rules for encoding documents in a human-readable and machine-readable format.

Classmate explanation: The fancy language that computers use to chat with each other. It's like their secret code that's both readable by humans and understandable by machines. XML helps them share information in a structured and organized way, making sure everyone is on the same page, even if they don't speak the same language.



Textbook definition: (YAML Ain't Markup Language): A human-readable data serialization format commonly used for configuration files.

Classmate explanation: A cool way for computers to read and write important settings. It's like a simplified language that makes configuration files look more like a conversation than a bunch of code. So instead of yelling at the computer in a confusing programming language, you can have a friendly chat with it in YAML and get things done smoothly.



Textbook definition:  Refers to the ability to build and customize applications without writing code, typically using visual interfaces or low-code platforms.

Classmate explanation: It's like having superpowers to create apps without typing a single line of code. Just imagine building something amazing with a few clicks and drag-and-drops. It's like turning into a wizard who can make software appear out of thin air. No code, no problem!

In closing, this ultimate A-Z guide has unlocked the mysteries of headless CMS terminology, equipping you with a solid understanding of its key concepts and terms. Whether you're a founder, maker, marketer, or part of the development process, this glossary has simplified the complex world of headless CMS for everyone.

By grasping the importance of APIs, back-end management, CDNs, CLI, encryption, and more, you now hold the key to confidently navigating the ever-changing landscape of headless CMS. It's not about mindlessly memorizing dull definitions; it's about grasping how these concepts come to life in the real world.

So, save this glossary to your bookmarks; it will be your trusty companion on your headless CMS journey. Whenever you need a refresher, it'll be there to guide you. Embrace the thrilling possibilities that headless CMS presents, and harness its full potential to propel your business forward in the digital age.

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