# ProUX > ProUX is a mobile-UX knowledge base and an AI chat grounded in it: verified UX, UI and CRO guidelines and principles, every answer cited to the page it stands on. Free reads all 50 guidelines in full; Pro reads the whole library. Canonical host: https://www.proux.design. The app lives at https://ask.proux.design. See https://www.proux.design/llms-full.txt for a summary of each page in its own words. ## Free library: UX Laws, Principles & Guidelines - [Index](https://www.proux.design/ux): 50 guidelines, free to read, grouped by cluster. ### Principles: Decision & simplicity laws - [Hick’s Law](https://www.proux.design/ux/hicks-law): Hick's Law says that the more choices you give someone, the longer they'll take to decide. When people face too many options, making a decision becomes harder and slower. - [Miller’s Law](https://www.proux.design/ux/millers-law): Miller's Law states that the average person can hold about seven (plus or minus two) items in their short-term memory. In simpler terms, most people can comfortably remember 5 to 9 pieces of information at a time. - [Tesler’s Law](https://www.proux.design/ux/teslers-law): Tesler’s Law states that every system has a certain amount of complexity that cannot be eliminated. The goal is to shift this complexity from the user to the system or vice versa. - [Occam’s Razor](https://www.proux.design/ux/occams-razor): Occam's Razor is a simple principle: when faced with multiple explanations or solutions, the simplest one is usually the best. - [Pareto Principle](https://www.proux.design/ux/pareto-principle): The Pareto Principle, also known as the 80/20 Rule, means that 80% of results come from just 20% of your efforts. This concept highlights how a small portion of actions often leads to the majority of outcomes. - [Parkinson’s Law](https://www.proux.design/ux/parkinsons-law): Parkinson's Law states that work expands to fill the time or space available for its completion. In simple terms, if you have more time or resources than needed, tasks tend to become more complicated than necessary. - [Doherty Threshold](https://www.proux.design/ux/doherty-threshold): The Doherty Threshold or the "Golden 60 Seconds" refers to the critical first minute of using a product or website. In that short window, users decide whether to continue using it or move on to something else. ### Principles: Interaction laws - [Fitt’s Law](https://www.proux.design/ux/fitts-law): Fitt's Law explains that the time it takes to click or tap on something depends on two things: how far away it is and how big it is. Simply put, larger and closer buttons or links are quicker and easier to use. - [Jakob’s Law](https://www.proux.design/ux/jakobs-law): Jakob's Law states that users prefer your app to work like the ones they already know. Since people spend most of their time using familiar apps and websites, they expect new apps to function in similar ways. - [Postel’s Law](https://www.proux.design/ux/postels-law): Postel's Law, also known as the Robustness Principle, advises that systems should accept unexpected or incorrect inputs without failing. In simple terms, your system should handle user mistakes without breaking. - [Weber’s Law](https://www.proux.design/ux/webers-law): Weber’s Law is a psychological principle stating that the smallest noticeable difference in a stimulus is proportional to its initial intensity. In design terms, it’s about how subtle changes - like slight increases in contrast or minor spacing adjustments - can help users perceive and understand your interface more effectively. ### Principles: Gestalt principles - [Law of Proximity](https://www.proux.design/ux/law-of-proximity): The Law of Proximity is a design principle that states we naturally group together items that are close to each other. In simple terms, when related elements are placed near one another, users instinctively see them as connected. This helps them understand your website or app more easily. - [Law of Similarity](https://www.proux.design/ux/law-of-similarity): The Law of Similarity is a principle from psychology that explains how our brains naturally group similar items together. When elements look alike - in color, shape, size, or style - we perceive them as part of the same group rather than as separate pieces. - [Law of Closure](https://www.proux.design/ux/law-of-closure): The Law of Closure means people naturally fill in missing parts of a visual to see it as complete. In UX design, this helps create interfaces that feel intuitive and whole, even when not every detail is shown. - [Law of Common Region](https://www.proux.design/ux/law-of-common-region): The Law of Common Region is a design principle that states we naturally group together things that are inside the same area or boundary. Think of items placed within the same box or section - they appear connected. - [Law of Continuity](https://www.proux.design/ux/law-of-continuity): The Law of Continuity is a design principle stating that people naturally follow smooth lines and patterns. When elements in a design flow seamlessly, users perceive them as connected, making it easier to navigate and understand the interface. - [Figure-Ground](https://www.proux.design/ux/figure-ground): Figure-Ground is a design principle that helps us see what's important on a page. Think of it like this: the "figure" is what you need to notice, and the "ground" is the background. By making the figure stand out from the ground, users can easily focus on key information without getting distracted. ### Principles: Core UX concepts - [Cognitive Load](https://www.proux.design/ux/cognitive-load): Cognitive load refers to the mental effort required to process information and complete tasks. In websites and apps, it measures how hard users have to think to navigate and use your interface. - [Mental Model](https://www.proux.design/ux/mental-model): A mental model is how users believe something works based on their past experiences and knowledge. It helps them understand and predict how to interact with new products or systems. - [Affordances](https://www.proux.design/ux/affordances): Affordances are design features that indicate how an object or interface should be used, allowing users to understand possible actions without needing instructions. - [Signifiers](https://www.proux.design/ux/signifiers): Signifiers are visual or audible cues like buttons, icons, or sounds - that show users how to interact with elements on a website or app. They make your design intuitive, helping users perform actions without confusion. - [Visual Hierarchy](https://www.proux.design/ux/visual-hierarchy): Visual hierarchy is a design principle that arranges elements to guide the viewer's eye to the most important information first. By manipulating size, color, contrast, and placement, it helps users quickly understand and focus on key content. - [Progressive Disclosure](https://www.proux.design/ux/progressive-disclosure): Progressive disclosure is a design approach that presents information to users gradually. Instead of showing everything at once, it reveals details step by step, displaying only what's necessary at each moment. This helps users focus on their current task without feeling overwhelmed. - [Feedback](https://www.proux.design/ux/feedback): Feedback in design is information given to users about their actions and the system's responses. It keeps users informed about what's happening, ensuring they always know where they stand. This clarity makes interactions smoother and more reassuring. - [Discoverability](https://www.proux.design/ux/discoverability): Discoverability is how easily users can find content or features on your website or app. It involves making important information visible and accessible without causing confusion. ### Principles: Memory & attention effects - [Aesthetic & Usability Effect](https://www.proux.design/ux/aesthetic-usability-effect): The aesthetic-usability effect is the idea that people perceive attractive designs as more usable and functional, even if they aren't. When something looks good, users feel more confident and satisfied using it. - [Von Restorff Effect / Isolation Effect](https://www.proux.design/ux/von-restorff-effect-isolation-effect): The Von Restorff Effect, also known as the Isolation Effect, is a psychological principle that suggests people are more likely to remember something that stands out from its surroundings. - [Zeigarnik Effect](https://www.proux.design/ux/zeigarnik-effect): The Zeigarnik Effect is a psychological principle explaining why we remember unfinished tasks better than completed ones. When we leave something incomplete, it stays on our mind, pushing us to recall and eventually complete it. - [Peak-End Rule](https://www.proux.design/ux/peak-end-rule): The Peak-End Rule is a concept from psychology that says people remember an experience based on two moments: First - The Peak: The most intense or memorable point. Second - The End: How the experience concludes. This means that no matter how average the rest of the experience is, these two moments heavily influence overall perception. - [Serial Position Effect](https://www.proux.design/ux/serial-position-effect): The Serial Position Effect is a psychological principle where people tend to remember the first and last items in a list better than those in the middle. This happens because our brains naturally pay more attention at the beginning and end of information. - [Banner Blindness](https://www.proux.design/ux/banner-blindness): Banner blindness occurs when users ignore content that looks like advertisements, even if it's important. Over time, people have learned to skip over anything that appears promotional. ### Guidelines: Trust & transparency - [Be Transparent with Total Costs to Build Trust and Keep Customers](https://www.proux.design/ux/be-transparent-with-total-costs-to-build-trust-and-keep-customers): Showing all costs upfront including item prices, shipping fees, taxes, and any extra charges—makes shopping easier for customers. It builds trust, reduces surprises at checkout, and encourages more people to complete their purchases. - [Why a Clear Return Policy Matters in eCommerce UX](https://www.proux.design/ux/why-a-clear-return-policy-matters-in-ecommerce-ux): A clear and visible return policy isn’t just a checkbox - it’s a core part of designing a user-centered eCommerce experience. For designers, grasping why this matters helps you make thoughtful decisions that impact users and businesses alike. - [Make Returns Easy: Build Trust and Boost Sales](https://www.proux.design/ux/make-returns-easy-build-trust-and-boost-sales): When returning items is simple, customers feel confident shopping with you again. Easy returns make them more likely to buy in the first place. - [Make Return & Shipping Info Easy to Find in the Footer](https://www.proux.design/ux/make-return-shipping-info-easy-to-find-in-the-footer): Placing clear links to your return policy and shipping details in the website footer gives customers instant reassurance about what happens after they buy, without forcing them to hunt for it. - [Why Rating Distribution Charts Are Essential for Trust in eCommerce](https://www.proux.design/ux/why-rating-distribution-charts-are-essential-for-trust-in-ecommerce): A rating distribution chart shows how many reviews a product has for each star rating. This simple tool builds trust and helps users make faster, more confident purchase decisions by giving them a clear, honest look at a product’s quality beyond just an overall average. ### Guidelines: Mobile experience - [Ensure Every Page Works Well on Mobile Devices to Keep Users Happy and Engaged](https://www.proux.design/ux/ensure-every-page-works-well-on-mobile-devices-to-keep-users-happy-and-engaged): Ensure that every page on your website is optimized for mobile users. If not, visitors may become frustrated and leave your site. - [Enable Pinch-to-Zoom for Product Images on Mobile](https://www.proux.design/ux/enable-pinch-to-zoom-for-product-images-on-mobile): Pinch-to-zoom is a simple gesture that lets users enlarge product images on their mobile devices. This feature is essential for eCommerce because it allows shoppers to see product details clearly on small screens, helping them make informed decisions. - [Improve Mobile Experience by Removing Auto-Rotating Carousels](https://www.proux.design/ux/improve-mobile-experience-by-removing-auto-rotating-carousels): Make your website friendlier for mobile users by removing slides that move on their own. Instead, use still images or let users control them manually. This simple change can make browsing easier and more enjoyable on phones. - [Speed Optimization Guidelines for eCommerce](https://www.proux.design/ux/speed-optimization-guidelines-for-ecommerce): A slow store loses shoppers before they see the product. Lighter code and a CDN keep pages quick enough to convert. ### Guidelines: Product content that sells - [Boost Sales with the 3-5 Image Rule for eCommerce Products](https://www.proux.design/ux/boost-sales-with-the-3-5-image-rule-for-ecommerce-products): In eCommerce, product images are key to helping customers decide to buy. The 3-5 Image Rule means every product should have at least 3 to 5 high-quality images showing it from different angles, in use, and highlighting its features. - [Essential Product Image Angles - A Quick Guide for eCommerce](https://www.proux.design/ux/essential-product-image-angles-a-quick-guide-for-ecommerce): Display products from multiple angles to create an immersive online shopping experience that builds customer confidence and drives sales. - [Use Clear and Simple Product Descriptions](https://www.proux.design/ux/use-clear-and-simple-product-descriptions): Product descriptions tell customers what a product does and why it’s useful. They should be easy to read and understand, helping shoppers make quick, confident decisions without confusion. - [Make Your Website Text Easy to Read and Engage Visitors](https://www.proux.design/ux/make-your-website-text-easy-to-read-and-engage-visitors): Simple changes to your website's text can make it easier to read, encouraging visitors to stay longer and increasing the chances they'll make a purchase. ### Guidelines: Finding & buying flow - [Help Customers Find What They Want Fast with Smart Filters](https://www.proux.design/ux/help-customers-find-what-they-want-fast-with-smart-filters): Use filters that make sense for each product category. Think about what customers are looking for and design filters to match. - [Prominently Highlight Main Categories on the Homepage](https://www.proux.design/ux/prominently-highlight-main-categories-on-the-homepage): Clear, visible category links on the homepage help shoppers instantly understand what you sell and quickly find the section they want. - [Fancy Menus Can Confuse Users: Stick to Familiar Navigation for Better Results](https://www.proux.design/ux/fancy-menus-can-confuse-users-stick-to-familiar-navigation-for-better-results): Fancy or unconventional menus might look interesting, but they often confuse visitors. Stick to menu designs that people already know to make your website easy to navigate. - [Make Cart Access Easy to Reduce Abandonment and Increase Sales](https://www.proux.design/ux/make-cart-access-easy-to-reduce-abandonment-and-increase-sales): After a customer adds an item to their cart, they should clearly see how to view their cart. This helps them feel confident and reduces the chances they'll leave without buying. - [Increase Cart Completion by Making Free Shipping Crystal Clear](https://www.proux.design/ux/increase-cart-completion-by-making-free-shipping-crystal-clear): To boost conversions, make free shipping information impossible to miss in the cart. Clearly state shipping costs and any thresholds that qualify for free shipping. This transparency reduces cart abandonment by reassuring customers about what they’ll pay and whether they can save on shipping. - [Clear Checkout Steps for Better Usability](https://www.proux.design/ux/clear-checkout-steps-for-better-usability): When customers can easily see where they are in the checkout process with honest, easy-to-understand steps and clear labels, fewer people leave without buying. Using simple progress bars and clearly named stages helps shoppers feel more sure about their purchase and more likely to finish buying what's in their cart. ### Questions: Applied questions - [Should I ask for email before or after showing shipping cost?](https://www.proux.design/ux/should-i-ask-for-email-before-or-after-showing-shipping-cost) - [Is guest checkout worth offering?](https://www.proux.design/ux/is-guest-checkout-worth-offering) - [How many form fields is too many in checkout?](https://www.proux.design/ux/how-many-form-fields-is-too-many-in-checkout) - [Where should the coupon code field go in checkout?](https://www.proux.design/ux/where-should-the-coupon-code-field-go-in-checkout) - [Should trust badges appear at checkout?](https://www.proux.design/ux/should-trust-badges-appear-at-checkout) - [Why do users abandon their cart at the payment step?](https://www.proux.design/ux/why-do-users-abandon-their-cart-at-the-payment-step) - [Should the cart show a delivery estimate?](https://www.proux.design/ux/should-the-cart-show-a-delivery-estimate) - [How should checkout handle a declined payment?](https://www.proux.design/ux/how-should-checkout-handle-a-declined-payment) - [Should I offer multiple payment methods or keep it simple?](https://www.proux.design/ux/should-i-offer-multiple-payment-methods-or-keep-it-simple) - [What does a good order confirmation screen contain?](https://www.proux.design/ux/what-does-a-good-order-confirmation-screen-contain) ## Pricing - [Pricing](https://www.proux.design/pricing): Free (100K tokens a month, the free library). Pro Quarterly $57 / ₹5,399 a quarter; Pro Yearly $131 / ₹12,499 a year (Early pricing, 42% off). Packs, never expire: Quick boost $5 / ₹499, Premium boost $20 / ₹1,899, Power pack $63 / ₹5,999. India pays in rupees plus 18% GST. Every first purchase carries a 5-day money-back guarantee. ## Training - [AI Product Design bootcamp](https://www.proux.design/training): a 2-day live online bootcamp for senior product designers, taught by Surinder Thakur. The November cohort runs Sat 7 and Sun 8 November, 11:30 to 15:00 IST · 10:00 to 13:30 GST. 7 live hours across 2 days back to back, 3.5 hours each, applied on your own product. One cohort, one set of dates. ## Legal and contact - [Terms of service](https://www.proux.design/terms) - [Privacy policy](https://www.proux.design/privacy) - [Refund and cancellation policy](https://www.proux.design/refund-policy) - [Contact](https://www.proux.design/contact): hey@proux.design ## About - [The Story Behind ProUX](https://www.proux.design/story), by Surinder Thakur (https://www.surinder.design/): "Good design moves the business. I spent 19 years proving it." 19 years of UX work, designing since 2007, NN/g certified, HFI CUA and CDPA, and why he built ProUX: "I built ProUX so the line from design to revenue stops being a consulting secret." ProUX is a product of Osum Studio Pvt Ltd, Punjab, India.