Glossary
Pattern library
What is a pattern library?
A pattern library is a documented collection of recurring design solutions (UI patterns) that solve common user interaction problems, such as search, filtering, onboarding, and error handling.
How it works
A pattern library differs from a component library in scope: components are individual UI elements (button, dropdown, card), while patterns are combinations of components that solve specific UX problems (a search-with-filters pattern, a wizard pattern, an inline-editing pattern). Each pattern entry typically includes the problem it solves, when to use it, the solution design, implementation guidelines, and examples. Well-known public pattern libraries include the GOV.UK Design System and Mailchimp's pattern library. Internal pattern libraries capture an organization's proven solutions and prevent teams from reinventing approaches to common problems.
Applied example
A team could consult a documented data-table pattern when designing sorting, filtering and pagination. Reuse may reduce duplicated work, but the pattern still needs assessment in the product’s context.
Why it matters
Pattern libraries share solutions and guidance across teams. Evidence of success in one setting does not guarantee success everywhere; maintain and test patterns as needs change.
Evidence note: Therese Fessenden: A documented pattern needs contextual evaluation.