Client-side personalization

What is Client-side personalization

Client-Side personalization refers to the process of tailoring and modifying website content in real-time, based on the behavior, preferences, and past interactions of the website visitor. It's executed on the user's browser once the website page loads, using JavaScript SDKs. This JavaScript code primarily ensures the user identification, fetching of personalized experience created specifically for the user and rendering them on the website page.

How does Client-side personalization work?

Advantages of Client-side personalization

1. Visual Editors: Most client-side personalization tools come with WYSIWYG (What You See Is What You Get) editors, which enable easy personalization of different elements within the webpage. In addition, there are out of the box widgets available that can be embedded within the webpages avoiding the need to write code.  
2. Ease of Implementation: It is generally easy to set up. You only need to incorporate a few lines of code on your website to ensure the SDK is integrated on all your webpages. 
3. Real-time Changes: It allows for real-time changes to be made on the webpage, as the tests are conducted after the webpage loads on the user's browser.

With client-side personalization, you can test hypotheses very quickly and then decide to deploy changes based on the experiment results.

Limitations of Client-side personalization

1. Works only on web browser: WYSIWYG visual editors work primarily with websites. Configuring similar experiences  on mobile apps and other digital platforms requires Server-side personalization capabilities. 
2. Feature management: Advanced experiments such as controlling the rollout of a new feature to your entire user base cannot be controlled using client-side personalization techniques. 
3. Impact on page load: Depending on the method of SDK Integration, a minor increase in page load time may be observed. 

When to use Client-side personalization

• E-commerce: Retailers can use client-side personalization to display customized product recommendations based on the user's browsing history or search behavior.
• Content Marketing: Publishers can personalize the content visible to each user based on their reading references or past engagement patterns.
• A/B Testing: Marketers can use client-side personalization to conduct A/B tests to identify the best-performing version of a webpage, ad copy, or call to action.
• Promotional Offers: Businesses can personalize promotional offers dynamically, driving conversions and enhancing customer engagement.

Server-side personalization

What is server-side personalization

In server-side, the personalization is done on the server side, meaning that the customized content is generated and delivered to the user's mobile app/browser directly from the server without the need for additional client-side processing. This allows for faster page load times and a seamless user experience.

How does server-side personalization work?

Advantages of server-side personalization

1. Consistency Across platforms: To ensure a seamless experience across App, website and other digital platforms & eliminate dependency on user's device or browser limitations, server-side testing is the best bet.
2. Speed & User Experience: If enhancing load times is a priority, server-side tests are most beneficial. They have quicker loading times than client-side experiments because they handle the variation before the page is sent from the server, eliminating any delay in page rendering that could occur with client-side testing. It avoids the flickering effect that sometimes happens in client-side testing when changes are made during or after the page load.
3. Complex Experiments: If you want to conduct a complex experiment that involves testing different algorithms, back-end processes, or core business logic, server-side testing would be the right choice. This could include testing a new recommendation algorithm for products or articles trying out new pricing logic or a new checkout flow.
4. SEO-Friendly: As the content is rendered at the server level and sent to the client’s browser, server-side testing is more SEO-friendly than client-side testing. The changes made through server-side testing will be properly indexed by search engines.
5. Security: Server-side testing is more secure as the logic resides on your server, not on the client's browser. It's ideal for testing sensitive areas, like payment processing or account login that require additional security measures.

Considerations for server-side personalization

1. Technical Expertise: Server-side personalization generally requires a higher level of technical knowledge than client-side testing, as modifications need to be made to the server-side code. Hence, you would need access to proficient developer resources and support.
2. Cost: Server-side personalization generally demands more development time and resources compared to client-side alternatives.
3. Speed of experimentation: If you need to conduct rapid iteration tests and observe quick results, client-side personalization could be more beneficial due to its higher implementation speed.

Client-side versus Server-side personalization