The Robustness Principle: How Postel’s Law Applies to UX/UI Design and Development

Postel’s Law, also known as the Robustness Principle, is a guideline for software design and development that was formulated by Jon Postel, an early pioneer of the Internet, in 1980. He stated it as follows: “Be conservative in what you do, be liberal in what you accept from others”. Postel was referring to the design of software protocols that enable communication between different computers on the Internet. He suggested that protocols should be strict and consistent in what they send to other machines, but flexible and tolerant in what they receive from them. This way, they can ensure compatibility and interoperability among various implementations of the protocol.

Postel’s Law has been widely adopted and applied in various fields of computer science and engineering, such as networking, security, programming languages, and web development. It is also a useful principle for user experience (UX) and user interface (UI) design and development. UX and UI are two crucial aspects of web design and development that determine how users interact with and perceive a website, and ultimately influence their satisfaction, engagement, and loyalty.

In this article, we will explain how Postel’s Law applies to UX/UI design and development, and what benefits it can bring to web design and development. We will also provide some practical examples of how Postel’s Law can be implemented in real-world scenarios.

How does Postel’s Law apply to UX/UI?

Postel’s Law can also be used as a guideline for UX/UI design and development. It implies that web designers and developers should be conservative in what they send to users, and liberal in what they accept from users.

Being conservative in what they send means that web designers and developers should follow established standards and best practices when creating UX/UI elements. They should provide clear and consistent information, feedback, and navigation to users. They should also optimize the performance, accessibility, and usability of their website across different devices, browsers, and platforms.

Being liberal in what they accept means that web designers and developers should anticipate and accommodate a wide range of user inputs, behaviors, and preferences. They should validate and format user inputs to prevent errors and confusion. They should also provide options and alternatives to users to suit their needs and goals. Moreover, they should design for inclusivity and diversity by considering different cultures, languages, abilities, and backgrounds of users.

What are the benefits of Postel’s Law for UX/UI?

Applying Postel’s Law to UX/UI can bring several benefits to web design and development. Some of these benefits are:

• Improved compatibility: By being conservative in what they send, web designers and developers can ensure that their website works well on different devices, browsers, and platforms. This can increase the reach and availability of their website to a wider audience.
• Enhanced usability: By being liberal in what they accept, web designers and developers can make their website more user-friendly and intuitive. This can improve the user satisfaction, engagement, and retention rates.
• Reduced errors: By being conservative in what they send and liberal in what they accept, web designers and developers can minimize the chances of errors occurring on their website. This can improve the reliability and quality of their website.
• Increased adaptability: By being conservative in what they send and liberal in what they accept, web designers and developers can make their website more resilient and adaptable to changes. This can help them cope with evolving user needs, expectations, and technologies.

Examples of Postel’s Law in UX/UI

To illustrate how Postel’s Law can be applied to UX/UI design and development, we will provide some examples of websites that follow this principle.

Example 1: Google

Google is one of the most popular search engines in the world. It follows Postel’s Law by being conservative in what it sends to users, and liberal in what it accepts from users.

Google is conservative in what it sends by providing a simple and minimalist interface that consists of a logo, a search box, a microphone icon for voice search, two buttons for Google Search and I’m Feeling Lucky, a menu icon for accessing other Google services, a sign-in button for accessing personal accounts, a footer with links to settings, privacy policy, terms of service, etc., . This interface is consistent across different devices (desktops, laptops, tablets, smartphones), browsers (Chrome, Firefox, Safari), platforms (Windows, Mac OS X), languages (English), etc., . Google also optimizes its performance by loading its homepage quickly , using HTTPS protocol for secure communication , and providing accessibility features such as keyboard shortcuts, screen reader support, high contrast mode, etc., .

Google is liberal in what it accepts by allowing users to enter any query in the search box, and providing relevant results based on the user’s intent, location, preferences, history, etc., . Google also validates and formats user inputs by correcting spelling errors, suggesting autocomplete options, offering related searches, etc., . Google also provides options and alternatives to users by allowing them to filter results by categories (images, videos, news, maps, etc.), time range (past hour, past week, past year, etc.), and other criteria (safe search, verbatim, etc.), . Google also designs for inclusivity and diversity by supporting different languages (over 100), regions (over 190), and cultures (local domains) .

Example 2: Amazon

Amazon is one of the largest e-commerce platforms in the world. It follows Postel’s Law by being conservative in what it sends to users, and liberal in what it accepts from users.

Amazon is conservative in what it sends by providing a clear and consistent interface that consists of a logo, a search box with a drop-down menu for selecting categories, a cart icon for accessing shopping cart, a sign-in button for accessing personal accounts, a menu icon for accessing other Amazon services, a navigation bar with links to departments, deals, prime, etc., a banner with featured products or promotions, a main content area with product listings or recommendations, a footer with links to customer service, policies, careers, etc., . This interface is consistent across different devices (desktops, laptops, tablets, smartphones), browsers (Chrome, Firefox, Safari), platforms (Windows, Mac OS X), languages (English), etc., . Amazon also optimizes its performance by loading its homepage quickly , using HTTPS protocol for secure communication , and providing accessibility features such as keyboard shortcuts, screen reader support, high contrast mode, etc., .

Amazon is liberal in what it accepts by allowing users to enter any query in the search box or browse through categories and filters to find products they are looking for. Amazon also validates and formats user inputs by correcting spelling errors, suggesting autocomplete options, offering related searches or products . Amazon also provides options and alternatives to users by allowing them to compare prices and features of different products , read reviews and ratings from other customers , add products to wish lists or shopping carts , choose delivery options and payment methods , etc. Amazon also designs for inclusivity and diversity by supporting different languages (over 10), regions (over 15), and cultures (local domains) .

Conclusions

Postel’s Law is a useful principle for web design and development. It suggests that web designers and developers should be conservative in what they send to users, and liberal in what they accept from users. By following this principle, they can create websites that are compatible, usable, reliable, and adaptable. This can enhance the user experience (UX) and user interface (UI) of their websites.

Bibliography

1 J. Postel, “Transmission Control Protocol - DARPA Internet Program Protocol Specification,” RFC 793, Sep. 1981. [Online].

2 J. Garrett, “Postel’s Law in UX Design: Striving for Robust and User-Friendly Experiences,” Adobe Blog, Jun. 2018. [Online].

3 J. T. Johnson, Laws of UX: Using Psychology to Design Better Products & Services. Sebastopol, CA, USA: O’Reilly Media, 2020, ch. 5.

[4] A. K. Pradeep, The Buying Brain: Secrets for Selling to the Subconscious Mind. Hoboken, NJ, USA: Wiley, 2010, pp. 68–69.

[5] S. Krug, Don’t Make Me Think, Revisited: A Common Sense Approach to Web Usability, 3rd ed. Berkeley, CA, USA: New Riders, 2014.

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