What is the difference between load testing and stress testing?

Load testing and stress testing are both types of performance testing in software testing and quality assurance. However, there are some key differences between the two:

1. Purpose: Load testing is conducted to evaluate the system's behavior under normal and expected load conditions. It helps determine if the system can handle the anticipated user load and perform optimally. On the other hand, stress testing is performed to push the system beyond its normal capacity and observe how it behaves under extreme conditions. It helps identify the system's breaking point and assess its ability to recover.

2. Load Level: Load testing focuses on testing the system under realistic and expected load levels. It simulates the number of users and transactions that the system is designed to handle. Stress testing, on the other hand, aims to test the system under excessive load levels that go beyond its normal capacity. It tests the system's ability to handle unexpected spikes in load or excessive resource consumption.

3. Objective: The objective of load testing is to ensure that the system can handle the expected load without any performance degradation or bottlenecks. It helps identify performance issues, such as slow response times or high resource utilization, under normal load conditions. Stress testing, on the other hand, aims to identify the system's limitations and weaknesses by subjecting it to extreme load conditions. It helps uncover issues like crashes, data corruption, or system failures.

4. Test Duration: Load testing is typically conducted over an extended period to observe the system's behavior under sustained load conditions. It helps identify any performance degradation or bottlenecks that may occur over time. Stress testing, on the other hand, is usually performed for a shorter duration, focusing on pushing the system to its limits and observing its behavior under extreme load conditions.

In summary, load testing evaluates the system's performance under normal and expected load conditions, while stress testing pushes the system beyond its limits to assess its behavior under extreme load conditions.