| Feature | Design System | Style Guide | Component Library |
|---|---|---|---|
| Scope | Principles, tokens, components, patterns, docs | Visual rules — colours, typography, spacing | Reusable UI components (code) |
| Maintained by | Design + development jointly | Design team | Development team |
| Includes code | Yes — production-ready components | No — design references only | Yes — code only, minimal docs |
| Cross-platform consistency | High — single source of truth | Moderate — interpretation varies | Moderate — code-focused |
| Onboarding value | High — covers decisions and rationale | Moderate — visual reference | Low–moderate — requires design context |
| Maintenance effort | Highest — living documentation | Low — updated per rebrand | Moderate — code versioning |
| Best for | Product teams scaling across platforms | Brand consistency in marketing | Dev teams needing reusable UI code |