What is 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 product team needs a data table with sorting, filtering, and pagination. Instead of designing from scratch, they consult the pattern library, which documents a proven data table pattern with specific guidance on filter placement, sort indicators, and pagination behavior, saving weeks of design iteration.
Why it matters
Pattern libraries capture and share proven solutions to common design problems, preventing each team from independently rediscovering the same solutions and ensuring consistency in how similar problems are solved.
