Stress testing is another industry term of performance testing. Though load testing & Stress testing are used synonymously for performance–related efforts, their goal is different.

Unlike load testing where testing is conducted for specified number of users, stress testing is conducted for the number of concurrent users beyond the specified limit. The objective is to identify the maximum number of users the system can handle before breaking down or degrading drastically. Since the aim is to put more stress on system, think time of the user is ignored and the system is exposed to excess load.

Let us take the same example of online shopping application to illustrate the objective of stress testing. It determines the maximum number of concurrent users an online system can service which can be beyond 1000 users (specified limit). However, there is a possibility that the maximum load that can be handled by the system may found to be same as the anticipated limit. The Table below illustrates the example specified.

Stress testing also determines the behavior of the system as user base increases. It checks whether the system is going to degrade gracefully or crash at a shot when the load goes beyond the specified limit.