Design Systems
Source of Truth
A source of truth is the single, agreed-upon place a team turns to for a design decision, so there is no debate about which version is correct. Traditionally this is a Figma file; increasingly it is the codebase itself.
Why it matters
Without one, teams drift into conflicting copies and waste time arguing over which button or color is the real one. A clear source of truth keeps design and engineering pointing at the same definitions.
In depth
A source of truth only works if everyone actually defers to it; a beautiful file that people ignore is worse than none, because it creates false confidence. The hard part is maintenance and trust, not the artifact itself. Many teams are moving the source of truth toward code and shared tokens so design and product cannot quietly fall out of sync.
Real-world example
When a team declares its design-system Figma library the source of truth for components, a designer copying an old button from a year-old file knows to replace it with the library version.
Principle
Source of Truth
One place the whole team trusts for the real answer.
Related terms