Be conservative in what you do, be liberal in what you accept from others.

As I explore the fundamental principles of UX design, I find that some resonate with me more than others. One of the concepts I recently studied is Postel’s Law, or the Robustness Principle, which suggests that systems should be liberal in what they accept and conservative in what they send. While I understand its importance, I found it less compelling than other UX laws, such as Fitts’ Law.

The idea behind Postel’s Law is clear: systems should be forgiving of user input while maintaining strict and predictable outputs. This principle is especially valuable in designing forms, search functions, and data processing systems, where users might make mistakes but still expect the system to understand their intent. For example, when a website allows different date formats or a search function provides relevant results despite typos, it creates a smoother user experience.

Despite its practicality, I found Postel’s Law less engaging because it feels more technical and behind-the-scenes compared to principles that directly shape interface interactions. Laws like Fitts’ Law or Hick’s Law focus on visible, tangible aspects of UX that immediately impact usability, whereas Postel’s Law often operates in the background. Perhaps this is why it didn’t capture my interest in the same way.

That said, I recognise that its impact is significant, especially in ensuring accessibility and inclusivity. A well-implemented Postel’s Law approach can reduce friction, making interfaces more intuitive and accommodating to user errors. While it may not be the most exciting principle to me at this stage of my learning journey, I appreciate its role in creating seamless digital experiences. As I continue to deepen my understanding of UX, I might come to see its value in a new light when tackling real-world design challenges.