Headless CMS systems distance content from presentation, meaning developers have the creative yet coding freedom to build fast, dynamic frontends. However, the more layered a digital experience HD imagery, cards adjusted to users, third-party offerings embedded within the more the construction can slow a site down if not done intentionally. Therefore, developers must depend upon certain techniques to ensure sites remain nimble and responsive, including lazy loading and progressive rendering. These rendering techniques are most effective when aligned with any rendering done by a headless CMS API with its own content.
What’s Lazy Loading?
Lazy loading is a performance enhancement technique that loads items that are not necessary, post-initial load. For example, rather than loading everything all at once from the start even if a user is never scrolling to that area lazily loading only loads what’s needed up-front and everything else is loaded when and if requested. In terms of headless CMS functionality, this can apply to images, video, and even content components driven by APIs that could load user reviews, testimonials, or a product carousel. Storyblok’s visual CMS supports this kind of modular content delivery by enabling editors to manage and preview component-based layouts without compromising load performance. By optimizing lazy loading properly, average load times per page decrease, there is proper bandwidth management, and the performance feels snappier—which is great for mobile users and lower-cost devices.
What’s Progressive Rendering?
Progressive rendering is the complete opposite. Instead of waiting for everything to load before rendering a page, progressive rendering allows parts of the interface to render as soon as it’s ready. This means users see some visual capacity relatively quickly, rather than waiting for everything. While this may be an attractive feature, it can also mean that there’s other data still loading underneath that the user may need before they can fully engage. In headless CMS creation, this is great when connecting to multiple APIs or creating large components that require extensive sourcing. The fact that there can be some level of loading allows for users to engage with the primary components while secondary collaborators load unbeknownst to the user, underneath.
Where Lazy Loading and Progressive Rendering Work Synergistically
While lazy loading and progressive rendering can exist independently, they work best for performance enhancement purposes in conjunction. For example, a product detail page can progressive render the title, price and buy button while lazy loading long descriptions, additional recommendations or API-driven reviews. This way, the users see what they need to see and have the ability to load more without overwhelming their sight or device capabilities immediately. Ultimately, they’re both designed to do the same thing and provide a speedier experience without feeling delayed as a result of low data or slow WiFi.
Adjusting Headless CMS APIs for Better Fetching Capabilities
To facilitate lazy loading and progressive rendering, developers need to adjust their CMS APIs for more granular, efficient fetching of information. That means building modular content models so that information can be fetched in portions instead of one large payload. CMS solutions with a GraphQL API are ideal for such situations as they allow more granular configurations and request/return of certain fields. RESTful APIs can be adjusted as well if there are endpoints for each content block or collection. Reducing the overall size of a response not only promotes ideal performance, but it also gives your frontend rendering logic much more room to breathe.
Lazy Loading Media
Media is often the heaviest lifting payload for increased load times. Lazy loading media is one way to keep performance at the highest levels. Developers can implement lazy loading through native browsers by using loading=”lazy” for images or iframes or they can create their own JavaScript solutions. When using a headless CMS for media hosting and media, responsive image techniques and CDN transformation services can help minimize their load impact as well. Placeholder techniques either a blurred image preview or loading skeleton can improve perceived speed while higher loaded assets load in the background.
Using Skeleton Loaders and Fallback Components for Content Blocks
Progressive rendering relies on visual placeholders for where content is going to show up. Also called skeleton loaders or fallback components, these techniques help guide user expectations and reduce perceived wait times. For example, a loading box, line, or sequence of greyed out boxes can show where a blog post will show up once it’s fetched. When utilizing a headless CMS, libraries like React or Vue can leverage the dynamic rendering to render skeleton components based on fetch status and replace them with real content once the API call returns. This keeps people engaged and is an accessible way to avoid layout shifts on load.
Loading What Users Need When They Need It Viewport and Progressively Rendered Loading
Beyond lazy loading and knowing what’s needed to trigger and render when, viewport psychic capabilities are necessary, too. Using the headless CMS, developers can determine which parts of the page need to render on load (i.e., above-the-fold content) versus things better rendered at a later time or below-the-fold, or interactive tab content. Likewise, using Intersection Observer API, developers can load components only after rendered; a fetch can be set to occur only when a certain component enters the viewport. For extremely modular applications built on headless CMSes, this is a perfect way to limit API calls and give focus to page load what’s necessary.
Caching States of Asynchronous APIs/CMS Connections with State Management Tools for Frontend Frameworks
Along these lines, since parts of the page load when required, it’s necessary to control states asynchronously, too. There are frontend framework libraries like React Query, SWR, or Vue’s composition API that help manage loading states for all API connections made through your headless CMS. These libraries cache the request and manage what’s rendered on the UI and when, as these libraries offer valuable useEffect hooks that separate fetching visibility from the UI. Thus, developers can separate their logic from the renderers, making their code more manageable while still allowing for real-time rendering.
Measuring Performance and Adjusting Loading Behavior Accordingly
Finally, what’s the point without measuring performance? Developers can determine how much their site load has improved through First Contentful Paint (FCP), Time to First Byte (TTFB), Time to Interactive (TTI), and Cumulative Layout Shift (CLS) via developer tools like Google Lighthouse. Other web measurement tools let you assess how various components load in other situations in different spaces. Real User Monitoring (RUM) platforms allow listeners to communicate when their sites load where they shouldn’t load, fine-tuning lazy loading behavior among components. From there, dev teams can adjust caching behaviors or how content is created in the headless CMS for better delivery, too.
Teaching Content Editors to Publish with Performance in Mind
There are no matches made in heaven between the flesh of the frontend and soul of the backend if the content is improperly formatted, or files are excessively large. Thus, teaching content editors to publish with performance in mind is crucial. They need to know to compress images before uploading, to make long-form content into chunked, reusable blocks and understand how their adjustments could impact lazy loading functionality. Many headless CMS on the market today come with validation rules or opportunities for automated optimization pipelines that can advocate for this so that editorial processes do not impede the performance objectives of the site.
Allowing for Personalization While Still Being Fast
Personalization requires dynamic rendering of content based on user behavior, location, or personal preferences but that doesn’t mean entities rendered need to impact web performance negatively. Developers can employ lazy loading and progressive rendering to ensure that static, non-personalized content loads first and anything dynamic and personalized is deferred. This means a user can start interacting with what brought them there, while other rendered elements load in the background without hindering the first render. Furthermore, when bringing in personalization from a headless CMS via API, it’s straightforward to fetch personalized info conditionally so that relevance does not impede load time.
Creating Adaptive Loading Based on Connection Contexts
People access the web from all different types of connection contexts from spotty 4G connections to hotel WiFi and everything in between. Adaptive loading allows developers to understand what’s needed and what’s not in real time. But along with lazy loading and progressive rendering, it helps create a harmonious approach where assets and blocks load or are deferred according to what users can manage. With a headless CMS, developers can ensure that under constrained conditions, only what’s needed is loaded and there is no unnecessary baggage preventing users from achieving what they want and the performance from being achieved.
Make Sure Critical Elements Load via Server-Side Rendering
There are elements of the user experience that cannot be lazy loaded, though, as they are either too critical to load at a delay (like above the fold content) or they’re rendered critical for SEO. Server-side rendering (SSR), an option with various frameworks like Next.js or Nuxt, renders anything critical to the user experience ahead of time so it appears as soon as it reaches the browser. For customers utilizing a headless CMS, SSR has the ability to render structured data immediately while still allowing for client-side lazy loading and progressive rendering down the line, for elements that are not time sensitive. The benefit? Engagement isn’t compromised for performance.
Implement a Component-Based Architecture to Maintain Frontend Loading Performance Over Time
Performance is not a one and done situation that occurs at the onset of a project. This is something that needs to be managed over time as the frontend evolves. The best way to maintain the performance status quo, then, is to utilize a modular approach. Components created with a lazy loading or progressive rendering mindset allows developers to adjust as needed. For a headless CMS site, this means using a headless CMS to build content models and applying the relative components to the frontend so that they can load independently and evolve independently. This architecture allows performance to be manageable now and adjustable down the line, seamlessly, when there are new features, third party solutions or new interface needs to integrate.
Conclusion: Delivering Speed and Sophistication in Tandem
Lazy loading and progressive rendering are integral considerations for optimal performance and user experience. When technology consumers are accustomed to rapid response and fluid interactions, the timing and implementation of information relative to access, retention, and satisfaction matter more than ever. Thus, lazy loading and progressive rendering are not just better-coded efforts but a mindset surrounding the different nature of product development that respects the consumer experience by allowing access in the quickest, most efficient manner.
When paired with a headless CMS, lazy loading and progressive rendering allow for content use cases that may not otherwise be possible. For one, developers have access to the infrastructure needed for experience-based front-end development that renders based on interactivity and need. Since a headless CMS separates the back and front end, content is modular; it can be created without certain aspects needing to be there, making it easier to render specific information versus everything all at once. For example, if a user scrolls down to see reviews and images of products, this information can load separately from the rest of the page especially if it is heavy media in nature.
Furthermore, lazy loading and progressive rendering can be triggered based on viewport awareness. For example, if team members include loading inception decimals, pieces of content can set to load based on what’s in the viewport-if it’s not viewable, it won’t load, decreasing bandwidth strain and increasing performance. Ultimately, however, efforts need to be measured to ensure that lazy loading and progressive rendering is beneficial to performance. Using insights from previous examples such as TTFB (time to first byte), FCP first contentful paint, and LCP (largest contentful paint) will allow teams to understand whether or not these efforts are working in their favor.
Ultimately, every client wants a competitive edge in their digital products. By incorporating a headless CMS with supplemental APIs focused on lazy loading and progressive rendering solutions, teams create a high-performance atmosphere that doesn’t impede workflow while also providing an intentional, custom experience. When things are faster, trust is built; when users see things happening rapidly on the front end, they’re more likely to hold onto products and other opportunities. Fluid experiences give companies a competitive advantage when scalability is a possibility without time-consuming barriers. Therefore, embracing these considerations is essential for effective, future-proof websites and applications.
