My strategy for SEO for single-page applications (SPAs)

The Internet is constantly evolving, and with the rise of modern Web technologies, the way we create interactive experiences online is also changing. Single-Page Applications (SPAs) are at the center of this innovation, allowing users to navigate smoothly without the traditional page reload.

This approach, which dynamically loads content and provides an app-like user experience, has many advantages, but also brings complex issues when it comes to SEO. The art of optimizing SPAs for search engines is a subtle balance between technical expertise and creative understanding of the user experience.

In this article, I will take you into the world of SEO for SPAs , where we will discover how to maximize the visibility of your web application in a landscape dominated by search engines.

What is a SPA?

A Single-Page Application (SPA) is a type of Web application or Web site that interacts with the user by dynamically rewriting new content instead of the traditional method of loading entirely new pages from the server. This means that after the initial page load, an SPA no longer needs to make full page requests to the server as the user navigates. Instead, an SPA loads only the necessary data, often via AJAX requests, and uses JavaScript to integrate the new information into the existing Web page, resulting in a much faster and seamless user experience(1). Thus, the content of the page changes without a change in the URL.

From a technical standpoint, an SPA is built around the concept of updating the user interface in real time, just as desktop applications do. It avoids the start-stop-start-stop nature of traditional URLs by providing the user with continuous and fluid interaction. This is achieved by using modern JavaScript frameworks such as Angular, React, or Vue, which take on the complexity of managing these dynamic updates and the state of the application.

This approach has its advantages, such as faster interaction times and an improved user experience, but it also brings challenges, especially in the realm of SEO. Since content is dynamically loaded, developers and SEO specialists must find creative solutions to ensure that content can still be crawled and indexed by search engines. This is where the art of SEO for SPAs comes in, combining technical dexterity with strategic planning to ensure application visibility and findability.

By the way, this challenge is less common than you might think, even when you look at the examples below. This often involves the interfaces that are also not indexed, such as behind the Netflix login.

Examples of well-known SPAs

Some common examples of SPAs are shown below. These are also often interfaces that are customized based on personal preferences.

  1. Gmail – Google’s email client is one of the most well-known SPAs, which allows users to navigate and perform various tasks without having to reload the page.
  2. Google Maps – Another well-known service from Google, this map application provides interactive features and data without full page refreshes.
  3. Facebook – Facebook’s News Feed is an SPA component, allowing users to scroll through their feed and perform various actions without reloading the page.
  4. Airbnb – Airbnb’s website is a SPA that provides users with a seamless experience when searching and booking accommodations.
  5. Netflix – Netflix’s client interface is an SPA, allowing users to browse movies and TV shows quickly and efficiently.
  6. Instagram – Much of Instagram’s web experience is built like an SPA, allowing users to scroll through their timeline without interruptions.
  7. Twitter – Although Twitter Lite is listed as a PWA, Twitter’s main website also has SPA features, with dynamically loaded content.
  8. GitHub – GitHub’s web interface also has SPA elements, especially in the project management and code exploration sections.

These websites use SPA technology to provide users with a smooth and responsive experience, reducing the need for page loads and allowing more dynamic interaction with the website. SPAs are particularly useful for complex, interactive Web sites with a lot of user interaction.

Technical challenges for SPAs

The biggest challenge for SEO with SPAs lies in their core functionality: using JavaScript to load content without a full page refresh. Search engines such as Google have invested significantly in improving their ability to handle JavaScript, but limitations still exist.

When a user performs an action that loads new content, search engines may not detect these dynamic updates. This leads to a discrepancy between what the user sees and what the search engine indexes.

This discrepancy is further complicated by the fact that SPAs often rely on client-side rendering, where the JavaScript frameworks run on the user’s browser to build the page (also read my articles on dynamic rendering and serverside/clientside rendering for this purpose). Although this provides a fast and interactive user experience, when crawling the site, a bot initially receives only the bare HTML template without the completed content. This means that the bot may be indexing an empty page, resulting in low SEO value.

An additional challenge is managing “crawl budget”(2). Search engines have a limited amount of resources they allocate to crawling a website, and SPAs can consume this budget quickly because of their complexity and the need to run JavaScript.

Is an SPA desirable for SEO?

“Back in the day,” HTML formed the skeleton of Web content, CSS provided the formatting, and JavaScript (JS) breathed life into pages with interactive features. From drop-down menus to dialog boxes, JS is indispensable on the Web today, with a presence on more than 98% of all sites. It is JavaScript’s ability to adapt page content to user actions that makes it so powerful.

A new trend is the rise of single-page applications. These differ from traditional Web sites that send a request to the server for every need for HTML, CSS, or JS. SPAs request all resources only once and then let the browser do the work.

This results in faster websites, which is crucial since studies show that visitors expect pages to load within three seconds. If it takes longer, they drop out. An SPA can be the salvation here, but incorrect implementation can actually cause an SEO nightmare.

In this article, we explore how SPAs are put together, the challenges they pose for optimization and how to ensure your SPA is SEO-friendly. When you apply SPA SEO correctly, search engines will understand your applications and rank well.

The core of SPAs

An SPA is a specific JavaScript-based Web development technology that does not reload pages after the initial rendering. React, Angular and Vue are known as the leading frameworks for building SPAs. They differ mainly in supported libraries and APIs, but are both champions in fast client-side rendering.

SPAs increase speed by reducing server-browser requests. However, search engines are less enamored with this JavaScript dexterity. The sticking point is that search engines do not perceive the site as users do, leading to inaccessible content. To a search engine, it looks like the page has yet to be populated, when in reality it is dynamically loading content.

Users benefit from SPA technology because it allows them to navigate smoothly through pages without awkward load times or layout shifts. SPAs cache all required resources locally after the initial request, allowing users to continue browsing relatively quickly even with a weak connection. Despite the extra effort for SEO, technology ensures that it is a permanent part of the Web.

What are possible challenges with SEO for SPAs?

When developing Single-Page Applications (SPAs), we encounter some inherent complications in terms of (SEO). These challenges arise primarily because SPAs rely on JavaScript to dynamically load content, which can affect indexability by search engines.

A primary problem is that traditional search engines are built to crawl and index static HTML content. SPAs initially serve an empty HTML shell that is filled with content only after JavaScript execution. This can lead to a discrepancy between what the end user sees and what the search engine detects, resulting in incomplete or completely missed indexing of content.

Furthermore, SPAs complicate the situation by using a single HTML page where the URL does not change with user navigation actions. This runs counter to the basic SEO principle where each unique content has its own unique URL. Without custom modifications, an SPA lacks the ability to provide relevant SEO metadata for each individual section or “page” within the application.

There is also the problem of the crawl budget. The heavy JavaScript required for SPAs can strain search engine crawl capabilities, meaning that larger parts of the site may be overlooked within the time search engines allocate to crawling a site.

It is therefore crucial for developers and SEO specialists to optimize the architecture of SPAs for search engines. This can be done through server-side rendering (SSR), where the content is generated server-side before being sent to the client, or by implementing pre-rendering techniques that allow search engines to receive a fully built-up page. In addition, dynamic meta tags and structured data must be properly deployed to ensure that each section of the SPA is treated as a unique entity by search engines.

For the biggest challenges, see also the table below.

ChallengeDescription
Indexing of contentSPAs load content dynamically with JavaScript, which can result in invisible content for search engines that index only HTML.
Crawling efficiencyHeavy JavaScript can exceed the crawl budget, meaning search engines may not index all of the SPA’s content.
Use of meta tagsDynamically loaded pages within an SPA often lack unique meta tags per section, which is essential for proper page indexing.
URL managementSPAs often do not change the URL during navigation within the app, which causes SEO problems because each content requires a unique URL.
Structure of URLs.The absence of a traditional link structure within SPAs can reduce the discoverability and value of links(3).
Server-side rendering (SSR)SSR is required to preload SPAs for search engines, but it can be complex to implement.
Pre-renderingPre-rendering generates static snapshots for crawlers, but requires additional setup and maintenance.
User engagementWhile SPAs can improve interaction, measurement issues can arise because traditional analytics are not optimized for SPAs.
Structured DataDynamically injecting structured data into SPAs is more technically challenging than in traditional Web sites(4).
Challenges for SPAs regarding SEO.

My strategy for SEO for SPAs

My biggest tips for dealing with SEO for SPAs are as follows (with a brief description for each point). Here I would immediately point out that if your organization runs an SPA, it is important to work with a specialist to create a customized strategy.

  1. Isomorphic JavaScript: use isomorphic, or “universal” JavaScript to generate pages server-side, so search engines do not have to output and render all JS files.
  2. Pre-rendering: pre-load all HTML elements and store them in the server cache so they can be served to search crawlers. This can be done through services such as Prerender or BromBone. This is often the easiest solution.
  3. Progressive enhancement with feature detection: implement feature detection to gradually enhance the experience with different code sources, making the base page accessible to both crawlers and users.
  4. Separate URLs for navigation: use distinctive URLs for different sections of the SPA by using the History API so that search engines can recognize different parts of the site as separate pages.
  5. Error page management: create separate views for each error code (such as 404, 500, etc.) and customize JS files to direct browsers to the correct view(5).
  6. Titles and descriptions for each view: provide unique titles and meta-descriptions for each section of the SPA and update them dynamically to reflect the content displayed.
  7. Robots meta tags: use robots meta tags to give instructions to search engines on how to crawl and index pages. This allows you to direct search engines to crawl and index the most important parts of the website, while avoiding duplication and mis-indexing.

These points provide an overview of how to approach SEO for SPAs to ensure better visibility and indexing.

Conclusion

Optimizing single-page applications (SPAs) for search engines requires a thoughtful mix of techniques and strategies. By using advanced solutions such as isomorphic JavaScript, pre-rendering, feature detection and the History API, you as a developer/SEO specialist can overcome the limitations inherent in SPAs.

Attention to detail in error handling, managing meta tags dynamically and implementing robots meta tags correctly are essential to making SPA content accessible and indexable by search engines. With these approaches, SPAs can compete effectively in the SERPs and ensure a strong online presence.

Senior SEO-specialist

Ralf van Veen

Senior SEO-specialist
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I have been working for 10 years as an independent SEO specialist for companies (in the Netherlands and abroad) that want to rank higher in Google in a sustainable manner. During this period I have consulted A-brands, set up large-scale international SEO campaigns and coached global development teams in the field of search engine optimization.

With this broad experience within SEO, I have developed the SEO course and helped hundreds of companies with improved findability in Google in a sustainable and transparent way. For this you can consult my portfolio, references and collaborations.

This article was originally published on 16 November 2023. The last update of this article was on 22 November 2023. The content of this page was written and approved by Ralf van Veen. Learn more about the creation of my articles in my editorial guidelines.