Design System Coexistence

Design system coexistence refers to situations where multiple design systems or component libraries operate within the same application or organization. Coexistence may be temporary during migration or ongoing when different systems serve different purposes.

What Is Design System Coexistence

Coexistence occurs when more than one design system is present. This might be a legacy system alongside a new system during migration, an internal design system alongside third-party components, or different design systems for different product lines within an organization.

Coexistence creates challenges: potential style conflicts, developer confusion about which system to use, increased maintenance overhead, and user experience inconsistencies. Managing these challenges enables practical coexistence while working toward clearer end states.

How to Manage Coexistence

Technical isolation prevents systems from interfering with each other. Style isolation through scoping, CSS modules, or CSS-in-JS prevents cascade conflicts. Component isolation through clear import boundaries prevents accidental usage of wrong components. Testing verifies systems work correctly in combination.

Clear guidelines help developers navigate multiple systems. Documentation should explain when to use which system, how to handle situations where both might apply, and what the migration plan looks like. Decision frameworks reduce confusion.

Visual consistency despite technical multiplicity maintains user experience. Even when different systems are used, they should produce coherent experiences. This might require coordination on core tokens, alignment on interaction patterns, or wrapper components that harmonize appearances.

Organizational coordination ensures stakeholders understand the coexistence situation. Communication about why coexistence exists, what the plan is, and how progress is being made prevents confusion and maintains support.

Migration planning works toward reducing coexistence where appropriate. Not all coexistence is problematic, but unplanned, indefinite coexistence often is. Clear plans for which systems will consolidate and timelines for doing so provide direction.

Key Considerations

• Coexistence has real costs that accumulate over time
• Not all coexistence can or should be eliminated; some is inherent
• Technical and organizational aspects both require attention
• User experience should not suffer despite technical coexistence
• Regular assessment of coexistence necessity prevents drift

Common Questions

Is design system coexistence always temporary?

Not necessarily. Some coexistence is inherent and appropriate: third-party components alongside internal ones, specialized tools with their own interfaces, or acquired products with their own established systems. Temporary coexistence during migration should be bounded and planned. Ongoing coexistence should be acknowledged and managed rather than ignored.

How can organizations minimize coexistence friction?

Minimizing friction involves investing in technical isolation to prevent conflicts, providing clear documentation and decision frameworks, maintaining communication about coexistence status and plans, and ensuring user experience remains coherent. When coexistence is intentional and well-managed, its friction is much lower than when it is accidental and neglected.

Summary

Design system coexistence occurs when multiple systems operate together, whether temporarily during migration or ongoing for legitimate reasons. Managing coexistence requires technical isolation, clear guidelines, visual consistency attention, organizational coordination, and migration planning. Acknowledging and actively managing coexistence minimizes its costs.