> For the complete documentation index, see [llms.txt](https://docs.maestro.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.maestro.dev/maestro-flows/javascript/generate-synthetic-data.md).

# Generate synthetic data

Generate random test data with the built-in faker object for names, emails, numbers, and more.

In Maestro, you can use the built-in DataFaker integration to generate dynamic, randomized data for your test. This is useful for bypassing unique-field constraints (like sign-up forms) and creating realistic testing environments without manual data entry.

### The `faker` object

Maestro provides a global `faker` object available within the JavaScript engine. This object is a wrapper around the DataFaker library and follows the same usage patterns and providers found in its Java documentation.

{% hint style="info" %}

#### DataFaker

For additional information about DataFaker, check its [documentation](https://www.datafaker.net/documentation/getting-started/#usage).
{% endhint %}

### Common data providers

The `faker` object provides access to a wide variety of data types, ranging from standard user information to specialized domains. 

{% hint style="info" %}

#### Providers available

Check the DataFaker to see all [Fake Data Providers](https://www.datafaker.net/documentation/providers/).
{% endhint %}

#### Basic identity data

Generate standard user information for forms:

* First Name: `faker.name().firstName()`
* Full Name: `faker.name().fullName()`
* Credit Card: `faker.finance().creditCard()` or via expression: `faker.expression('#{finance.creditcard}')`

#### Numbers 

Generate random ranges or specific number patterns:

* Between Range: `faker.expression("#{number.numberBetween '1' '10'}")`
* Digits: `faker.number().digits(5)`

#### Placeholder 

DataFaker also supports "fun" providers for non-critical placeholder text:

* Lord of the Rings: `faker.lordOfTheRings().character()` or `faker.lordOfTheRings().location()`

### Usage examples

You can use `faker` within `evalScript` to store values in the `output` object, or directly inside UI commands.

{% tabs %}
{% tab title="In-line data generation" %}

```yaml
- launchApp
- inputText:
    text: ${faker.name().firstName()}
- inputText:
    text: ${faker.internet().emailAddress()}
```

{% endtab %}

{% tab title="Complex expressions" %}
Using expressions allows you to combine multiple faker providers into a single string:

```yaml
- evalScript: '${output.bio = faker.expression("#{name.fullName} lives in #{address.city}")}'
- console.log: ${output.bio}
```

{% endtab %}
{% endtabs %}


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