The word ‘Post’ denotes ‘After In Time’ and ‘Processor’ denotes ‘Execution’, hence ‘Post Processor’ means something that is executed later. In JMeter, there are some elements which execute after the execution of the parent element. These elements help to fetch the data from the response or instruct JMeter to perform the next action depending on the response. Such JMeter elements are called Post Processor elements.
Make a note that ‘Post-Processor’ always runs before Assertion. Hence Post Processor does not have access to any Assertion Results.

If a sampler has a Post Processor as its child element then the Post Processor will execute just after that sampler. The execution sequence will be like this:
Pre Processor => Sampler => Post Processor
Possible Parent element(s) of Post Processor:
You can add a Post Processor under the following elements:
- Test Plan
- Thread Group
- Test Fragment
- Sampler
- Logic Controller
- Non-Test Element
Possible Child Element(s):
- NA
You can not add any element under a ‘Post Processor’. Hence it does not have any child element.
Following is the list of available Post Processors:
- CSS Selector Extractor
- JSON Extractor
- JSON JMESPath Extractor
- Boundary Extractor
- Regular Expression Extractor
- JSR223 PostProcessor
- Debug PostProcessor
- JDBC PostProcessor
- Result Status Action Handler
- XPath Extractor
- XPath2 Extractor
- BeanShell PostProcessor
You may be interested:
- Performance Testing Tutorial
- Performance Engineering Tutorial
- Micro Focus LoadRunner Tutorial
- NeoLoad Tutorial