Design patterns are reusable solutions to problems that come up again and again in interface design. Breadcrumbs show users where they are. An error summary lists every form mistake at the top of the page.
The idea comes from architect Christopher Alexander's A Pattern Language (1977). Jenifer Tidwell applied it to interaction design in the late 1990s. In UX, a pattern describes when and why to use a solution. A component is the built, reusable piece of code. Software engineering has its own "design patterns" (Gang of Four), which cover code structure, not interfaces.
Use cases
Skipping established patterns can make interfaces inconsistent and force users to learn new interactions.
Invented navigation: A retail app hides its menu behind a custom gesture. Users can't find categories.
Inconsistent inputs: One team uses a calendar widget while another uses 3 text fields for dates. Users encounter different interaction methods in the same checkout.
Wrong pattern: A team adds infinite scroll to a results page where users need to compare items. They lose easy access to the footer and page position.
How it's used in practice
Check existing libraries first. Search established pattern libraries such as GOV.UK or UI-Patterns.com before designing from scratch.
Document the context. Each pattern should explain the problem it solves, when to use it, when not to use it, and provide examples.
Test it in context. Validate the pattern against the specific flow, user goal, and content rather than assuming a familiar solution will work everywhere.
Standardize repeated problems. When the same problem appears across a product, use one established approach unless there is a clear reason to introduce another.
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Pro-tip: Write the "when not to use" section first. It prevents a useful pattern from being applied where it doesn't fit.
Challenges & limitations
Stale libraries: Pattern libraries can become outdated as products, technology, and user needs change.
Over-standardization: Applying the same pattern everywhere can prevent teams from addressing genuinely different user needs.
Bad patterns spread: Reuse can preserve harmful or manipulative solutions, allowing dark patterns to spread across products.
