JMeter is an application that offers several possibilities to configure and execute load, performance and stress tests using different technologies and protocols.
It allows simulating different type of requests against all kind of databases, FTP, HTTP, HTTPS or other kind of servers.
It is probably good to explain briefly what all these concepts mean:
- Load tests: These kind of tests take the systems or applications tested to the extremes that they were designed and required for. They are used to measure systems and applications behavior under extreme conditions.
- Performance tests: These tests are used to check how the system behaves in terms of performance, that is, how the system responds and how is its stability for a specific workload.
- Stress tests: These tests try to break or overwhelm the system by loading more resources and taking its modules outside the limits that were designed.
Originally JMeter was designed to test web applications, but its functionality has expanded and nowadays allows testing against almost any kind of program and can be used to perform functional tests in your applications.