---
title: "JSR223 PostProcessor"
description: "Configure the JMeter JSR223 PostProcessor post-processors: properties, defaults, and practical usage notes for building reliable load tests."
url: https://docs.jmeter.ai/components/jsr223-postprocessor/
lastUpdated: 2026-10-01
source: docs.jmeter.ai
---

# JSR223 PostProcessor

*Part of the **Post-Processors** category. Also documented in context in the [full Component Reference](/user-manual/component-reference/#jsr223-postprocessor).*

**TL;DR:** the JSR223 PostProcessor runs Groovy code right after its parent sampler completes — the go-to spot for extraction logic too complex for the JSON or Regular Expression Extractor (nested conditionals, multi-step parsing, custom validation).

The JSR223 PostProcessor allows JSR223 script code to be applied after taking a sample.

| Name | Required | Description |
| --- | --- | --- |
| Name | No | Descriptive name for this element that is shown in the tree. |
| Language | Yes | The JSR223 language to be used |
| Parameters | No | Parameters to pass to the script.     The parameters are stored in the following variables:      - `Parameters` - string containing the parameters as a single variable - `args` - String array containing parameters, split on white-space |
| Script file | No | A file containing the script to run, if a relative file path is used, then it will be relative to directory referenced by “`user.dir`” System property |
| Script compilation caching | No | Unique String across Test Plan that JMeter will use to cache result of Script compilation if language used supports `[Compilable](https://docs.oracle.com/javase/8/docs/api/javax/script/Compilable.html)` interface (Groovy is one of these, java, beanshell and javascript are not)      :::note See note in JSR223 Sampler Java System property if you’re using Groovy without checking this option ::: |
| Script | Yes (unless script file is provided) | The script to run. |

Before invoking the script, some variables are set up.
Note that these are JSR223 variables - i.e. they can be used directly in the script.

- `log` - ([Logger](https://www.slf4j.org/api/org/slf4j/Logger.html)) - can be used to write to the log file
- `Label` - the String Label
- `FileName` - the script file name (if any)
- `Parameters` - the parameters (as a String)
- `args` - the parameters as a String array (split on whitespace)
- `ctx` - ([JMeterContext](https://jmeter.apache.org/api/org/apache/jmeter/threads/JMeterContext.html)) - gives access to the context
- `vars` - ([JMeterVariables](https://jmeter.apache.org/api/org/apache/jmeter/threads/JMeterVariables.html)) - gives read/write access to variables:  `vars.get(key); vars.put(key,val); vars.putObject("OBJ1",new Object()); vars.getObject("OBJ2");`
- `props` - (JMeterProperties - class java.util.Properties) - e.g. `props.get("START.HMS");` `props.put("PROP1","1234");`
- `prev` - ([SampleResult](https://jmeter.apache.org/api/org/apache/jmeter/samplers/SampleResult.html)) - gives access to the previous SampleResult (if any)
- `sampler` - ([Sampler](https://jmeter.apache.org/api/org/apache/jmeter/samplers/Sampler.html))- gives access to the current sampler
- `OUT` - System.out - e.g. `OUT.println("message")`

For details of all the methods available on each of the above variables, please check the Javadoc

### Common gotchas

- `prev` (the `SampleResult`) gives you `prev.getResponseDataAsString()`, headers, response code, and timing — you rarely need to re-parse anything the built-in extractors already exposed.
- Anything you `vars.put(...)` here is visible to *later* samplers in the same thread, not earlier ones — order in the test tree matters.
- If you’re just pulling one JSON field, reach for the [JSON Extractor](/components/json-extractor/) first; scripting adds maintenance cost that’s only worth it for genuinely custom logic.
- Exceptions here don’t automatically fail the sample — catch and call `prev.setSuccessful(false)` (or similar) if a parsing failure should count as a test failure.

## Related

- [Correlation & Dynamic Values](/topics/correlation-dynamic-values/)
- [Regex Extractor Builder](/tools/regex-tester/)
- [JSR223 Groovy Scripting Guide](/topics/jsr223-groovy-scripting-guide/)
- [Full Component Reference](/user-manual/component-reference/)
- [Functions and Variables](/user-manual/functions/)