There are two basic types of software application monitoring: real user monitoring and synthetic testing. When looking at an application monitor, it is essential to understand the differences. Understanding why some application monitors succeed and others fail can help you make the right decision for your business. Here are some common application monitors and their differences.

Real user monitoring is the process of gathering performance data from a real user. Vendors provide real-time application performance data to support the design and development of new product or service offerings. When a user does a search or visits a particular web page, the information gathered can be used to generate relevant performance reports. Real-time web page tests provide valuable insights that help engineers and developers determine whether new functionality can be offered. In contrast, synthetic testing is a method for gathering performance data and analyzing it without user interaction.

Historically, synthetic testing was performed by network operators, system administrators, and IT professionals who understood the risks of performing an actual user test. Today, most synthetic testing methods are outsourced to specialized companies that perform the tests automatically. Vendors offer automated systems that create mock or realistic web page tests and use real-time data to determine functionality. Depending on the needs of the testing environment, different types of tests can be developed. The common synthetic test is the page test, which analyzes the performance characteristics of individual web pages and checks for compatibility and security issues.

Synthetic testing is not recommended for low-level testing. It can provide false positive results, which can impact the confidence of end users in the product or service. Furthermore, it doesn't allow the end-user to see the end-user experience, which can lead to inaccurate user experience expectations. Synthetic testing must provide verifiable and accurate results using real data from actual users. The test data must be taken at various point in the product or service's lifecycle to capture behavior and trend changes over time. This allows the tester to make educated guesses about potential issues and difficulties that might be encountered during actual usage.

Another advantage of synthetic testing is that it allows quick determination of test cases' validity using a single data set. The test cases can be run in parallel in order to identify differences and similarities between actual and simulated user experiences. The test cases also serve as an estimate of what would occur under different operating conditions. A well-constructed test case should allow testers to make fast, concise estimates and adjust their strategy accordingly.

Although synthetic testing provides a quick means for determining if a product or service meets the specific requirements, this method does not provide detailed insight into product or service behavior. Detailed data collection from real user monitoring studies is necessary to understand user expectations and to establish a baseline from which improvements can be made. Because synthetic testing relies on approximate calculations and estimates rather than on rigorous scientific methodology, it is important to remember that the resulting conclusions should only be drawn after careful analysis of the test data.