---
title: "Debug ViewHelper <f:debug>"
manual: "Fluid Explained"
version: "main"
permalink: "https://docs.typo3.org/permalink/fluid:typo3fluid-fluid-debug"
source: "ViewHelpers/Fluid/Debug.rst"
rendered: "2026-09-26T08:24:58+00:00"
---

# Debug ViewHelper `<f:debug>` {#typo3fluid-fluid-debug}

> [!NOTE]
> This reference is part of the documentation of Fluid Standalone.
> If you are working with Fluid in TYPO3 CMS, please refer to
> [TYPO3's ViewHelper reference](https://docs.typo3.org/other/typo3/view-helper-reference/14.3/en-us/Global/Debug.html) instead.

This ViewHelper is only meant to be used during development.

## Examples {#examples}

### Inline notation and custom title {#inline-notation-and-custom-title}

```php
{object -> f:debug(title: 'Custom title')}

```

Output:

```php
all properties of {object} nicely highlighted (with custom title)

```

### Only output the type {#only-output-the-type}

```php
{object -> f:debug(typeOnly: true)}

```

Output:

```php
the type or class name of {object}
```

Go to the source code of this ViewHelper: [DebugViewHelper.php (GitHub)](https://github.com/TYPO3/Fluid/blob/main/src/ViewHelpers/DebugViewHelper.php).

**Arguments**

The following arguments are available for the debug ViewHelper:

-   **html**

    -   *Type:* boolean
    -   *Default:* false

    Render HTML. If false, output is indented plaintext

-   **levels**

    -   *Type:* integer
    -   *Default:* 5

    Levels to render when rendering nested objects/arrays

-   **typeOnly**

    -   *Type:* boolean
    -   *Default:* false

    If true, debugs only the type of variables