Scalability is the ability of an application to handle growth—whether more users, more data, or more traffic—without performance degradation.
Why It Matters
Applications that can't scale fail at the worst possible moment (viral success, peak traffic)—building scalability in from the start prevents these crises.
When to Use This
- Handling 10x traffic during product launches
- Growing database without query slowdowns
- Adding server capacity during high-traffic events
- Supporting business growth without rearchitecting
Examples
- Adding load balancer to distribute traffic across servers
- Database read replicas for reporting queries
- Caching reducing database load as traffic grows
- Queue processing handling batch jobs without affecting UX