> For the complete documentation index, see [llms.txt](https://documentation.hak5.org/hak5-usb-rubber-ducky/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.hak5.org/hak5-usb-rubber-ducky/advanced-features/jitter.md).

# Jitter

## Overview

Jitter is a feature which varies the cadence, or delay, between individual key presses. When enabled, jitter affects all keystroke injection commands. Jitter delays are randomly generated at payload deployment, rather than statically compiled delays such as when using the `DELAY` command. This means that each deployment of a jitter-enabled payload will produce different results.

## $\_JITTER\_ENABLED

Jitter is enabled and disabled by changing the boolean value of the `$_JITTER_ENABLED` internal variable. By default the value of this variable is `FALSE`. To turn jitter on, set the variable to `TRUE`.

### Example

```
REM Example Jitter

ATTACKMODE HID STORAGE
DELAY 2000

$_JITTER_ENABLED = TRUE
WHILE TRUE
    STRINGLN The quick brown fox jumps over the lazy dog
END_WHILE
```

* The test string is typed continuously with a modulated delay between each key press.

## $\_JITTER\_MAX

The `$_JITTER_MAX` internal variable sets the maximum time between key presses in milliseconds. The default is 20 ms.

### Example

```
REM Example Jitter with increasing $_JITTER_MAX

ATTACKMODE HID STORAGE
DELAY 2000

$_JITTER_ENABLED = TRUE
WHILE TRUE
    STRINGLN The quick brown fox jumps over the lazy dog
    $_JITTER_MAX = ($_JITTER_MAX * 2)
END_WHILE
```

#### Result

* With each iteration of typing the test string the jitter limit is doubled, yielding slower and more sporadic typing.