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Aleksander Furgal Published: 5 May 2023 8 min to read

JavaScript SEO: Choosing a Framework for Rendering Your Dynamic Content

While JavaScript-based websites can offer a rich user experience, search engines have historically struggled to fully process JavaScript. However, the stuation has improved significantly in recent years.

Major search engines like Google have made significant progress in understanding JavaScript content, and programmers have developed techniques to crawl, render, and index websites that rely on this technology.

At the same time, there are still some challenges that developers need to be aware of when it comes to JavaScript SEO. For example, certain JavaScript techniques can still present obstacles to search engine crawlers, and there are some best practices that developers can follow to ensure that their JavaScript-based websites are optimized for search engine visibility and user experience.

In this article, we will explore the nuances of JavaScript SEO, including the current state of search engine understanding of JavaScript, the challenges that still exist, and best practices that developers can follow to ensure that their JavaScript-based websites are optimized for both search engine visibility and user experience.

How does Google crawl and index JavaScript?

There are three phases in which crawlers process JavaScript web pages – crawling, rendering, and indexing.

In order to optimize your crawl budget, it’s imperative that you have a clear understanding of all three.


#1 Crawling

Using an HTTP request, Googlebot retrieves a URL from the crawl backlog. The first thing it examines is whether the robots.txt file permits crawling. If the file identifies the URL as disallowed, Googlebot will bypass the URL. The system then parses the response for additional URLs within the href attribute of HTML links and adds the allowed URLs to the crawl backlog.

The method is effective for server-rendered pages where the HTML in the HTTP response contains the entire page’s content. JavaScript websites can utilize the app-shell model where the initial HTML does not have primary content. Googlebot must execute JavaScript before it can view the actual page content that JavaScript generates.


#2 Rendering

Google determines which resources are needed for rendering the page’s primary content. Large-scale JavaScript rendering is more resource-intensive and expensive. Downloading, parsing, and executing JavaScript in higher volumes requires substantial computing capacity.

Google may therefore delay rendering JavaScript until a later date. An autonomous Chromium renders the page and executes the JavaScript as soon as Googlebot’s resources permit. Then, Googlebot parses the rendered HTML for connections and places the URLs it discovers in a queue for indexing.

Web Rendering Service (WRS) is the system that manages the rendering procedure for Google. When the WRS receives URLs, it renders them and returns the HTML for further processing.


#3 Indexing

After executing JavaScript, Google utilizes the rendered HTML to index the pages. Google can only index content once the JavaScript has been rendered, and scanning a JavaScript-based website is a complex routine.

While recent enhancements to Googlebot have reduced the time between crawling and rendering, there is no assurance that Google will execute the JavaScript code pending in its WRS queue for reasons like – Blocked in robots.txt, errors, and timeout.

JavaScript can cause SEO issues if there is a dependency on it by the primary content, but Google fails to render it.


How does JavaScript affect SEO?

JavaScript is useful for creating interactive pages, but search engine optimization can be difficult. Search engines need to render pages before ranking them. Rendering is a process related to crawling in which search engines try to view documents from a web page visitor’s perspective. JavaScript may lead to search engines inaccurately rendering pages, decreasing search rankings.

Pages with HTML and CSS are straightforward for search engines to render. The crawlers will read the HTML to identify the page’s content, and the CSS will be analyzed to assess its presentation. If the page contains JavaScript, some content may be overlooked.

Using excessive JavaScript or neglecting to optimize it can slow down the page. Pages with more JavaScript can be more challenging for web browsers to load. In general, faster-loading sites have better rankings than slow-loading ones.


Here at ASPER BROTHERS, we always urge developers to prioritize SEO when using JavaScript. While JavaScript allows for creating rich and dynamic experiences, it’s important to remember that search engines still play a critical role in driving traffic and attracting users. SEO should be considered from the outset of all projects because, ultimately, balancing JavaScript’s power with SEO best practices will contribute to overall business success. Mike Jackowski COO, ASPER BROTHERS Let's Talk


Page rendering type and its influence on SEO

There are multiple rendering processes that you should be aware of when deciding on a JavaScript framework.

Having a clear understanding of these rendering processes and their implications for SEO will help you create websites that are optimized for both search engines and users.


#1 Server-side rendering

Server-side rendering means that page rendering takes place on the server before being provided to the client (a browser or crawler). The rendering process occurs in real time and treats visitors and crawlers equally. After the initial launch, JavaScript code is still usable and executed.

Google recommends server-side rendering because it increases the speed of your website for both consumers and search engine crawlers, as every element is available in the initial HTML response. Developers may find it challenging to implement, and the Time to First Byte (TTFB) may be sluggish because the server must render web pages on the fly.


#2 Client-side rendering

In Client-side rendering, the client renders JavaScript using the DOM. When the client must execute JavaScript, the above-described computational issues become more apparent when Googlebot attempts to crawl, render, and index content.

Thus, although client-side rendering is prevalent, search engine algorithms have difficulty with it, and it is not optimal for SEO.


#3 Dynamic rendering

Dynamic rendering is a feasible alternative to server-side rendering. It detects bots having issues with JavaScript-generated content and provides a rendered version from the server minus JavaScript. Meanwhile, the users will see the client-side-rendered version.

Dynamic rendering is not recommended by Google. It adds unnecessary complexity, especially for a bigger website with frequently changing content that requires rapid indexing. However, if your website depends on social media and messaging applications that require access to the page’s content or if the essential algorithms of your site cannot support some of your JS features, dynamic rendering might be a good idea.


Choosing a JavaScript framework for best SEO

As there are no dominant SEO frameworks, you can make your decision based on your product requirements. Frameworks that support server-side rendering offer advantages in faster load times and easier search engine crawling. These result in higher rankings for your site.

The JavaScript frameworks most widely used for SEO include:

  • Next.JS: Next.JS is a React-based framework that enables the development and scalability of web pages by rendering them on the server instead of the client-side browser. Server-side rendering in Next.JS allows bots and crawlers to better understand website information by detecting metadata and indexing web pages faster.
  • Gatsby: Gatsby is an open-source framework that helps create applications that take advantage of the finest features of other frameworks, such as React, GraphQL, and Webpack. Gatsby combines the quickness of a server-rendered site with interactions by utilizing only static files. Gatsby converts the website code into a single HTML file containing fixed assets, making Gatsby SEO straightforward.

Gatsby is suitable if your content change frequency is lower. Next.JS, on the other hand, is a better choice when building complex websites with a high amount of server interaction.


How to achieve better JavaScript SEO?

JavaScript is vital for constructing scalable and easy-to-maintain websites. However, some JavaScript implementations may harm search engine visibility.

Below, we will discuss different ways in which JavaScript can be optimized for better SEO.


#1 Build your site based on Server-side rendering

Server-side rendering (SSR) is an optimal technique to make your JavaScript application SEO-friendly. Here, the server renders your application as HTML and sends it to the client browser. It simplifies rendering and makes it easier for search engines to index your website’s content.

Static Site Generation (SSG) is another way to create HTML at build time rather than runtime in SSR. With SSG, websites load faster as the HTML content renders before the user submits a request. On the other hand, every time there is a change, the website must be completely rebuilt and refreshed.

Both ways of rendering produce pages quickly, which will benefit their search engine rankings. SSG renders faster than SSR; however, SSR is a better choice for web applications with a high volume of data and frequent updates like stock levels for online stores, etc.


#2 Use as few JavaScript components as possible

It’s common to use jQuery UI and jQuery Mobile libraries. Although all potential library components are available, you may need only a few. It is advisable to reduce the elements included in your library package so website pages load faster and deliver a better visitor experience.

You must ensure the user experience is as good as possible to prevent a drop in Google search engine traffic. For instance, search engine algorithms penalize websites for having too many advertisements above the fold and if it lowers the visibility of the actual site content due to scrolling. Ensure your ads do not obstruct your content and contain less JavaScript.


#3 Choose the proper JavaScript framework

Choose a web framework for SEO based on your specific requirements. Explore the features of each framework and how they align with your long-term objectives. If you are making a lightweight website that renders rapidly, Next.JS is a good choice for ensuring it is adequately optimized for search engines.

If your website relies heavily on user interaction, Angular or React SEO are your best options, as they run faster. You should conduct thorough research before deciding on a JS framework.


#4 Use partial or lazy hydration

With the lazy hydration method, you render only the user-required elements, which will improve both page load times and search engine visibility. It can considerably lengthen the time required to render a page, particularly for large sites with deeply nested HTML. That’s why you should minimize the quantity of hydration that takes place.

While most applications cannot avoid hydration costs, specific SPAs permit isolating JavaScript hydration to particular segments. This method is known as “partial hydration.” In general, only the interactive components of an application, such as the interface and comments section, are hydrated, while the content stays fixed. It enables you to conserve resources and substantially enhance your site’s performance, user experience, and SEO.


#5 Delay JavaScript Execution

The delay function in JavaScript is an effective method to decrease page load times. You need to delay the launch of JavaScript until the user interacts with your page with actions like scrolling or clicking. As soon as the user interacts, all JS gets loaded inline.

You should only use the delay function if the page layout does not change when JavaScript is executed upon interaction, as this could result in a poor user experience.


#6 Manage your external tools

Everything you add to your website will impact its performance. It is because every component—including tracking tags, graphics, and fonts—increases page weight and the number of resources required to load a page.

The more Javascript code you put into your website, whether it loads asynchronously or not, the heavier the page will be, which can slow down the loading process. Installing external tools only when necessary is another technique for increasing page speed. Usually, they are most important during marketing campaigns, website updates, or peak sales periods.



JavaScript is a powerful and versatile technology that has enabled developers to create highly interactive and engaging websites. While there have been concerns about its impact on search engine optimization, the reality is that search engines have made significant strides in understanding and processing JavaScript content in recent years.

By following best practices and paying attention to potential obstacles, developers can ensure that their JavaScript-based websites are optimized for search engine visibility and user experience.

Ultimately, JavaScript SEO is not an either-or proposition. By understanding the nuances of this technology and following best practices, developers can leverage the power of JavaScript while ensuring that their websites are accessible and discoverable by both users and search engines alike.


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Aleksander Furgal

Content Specialist



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