> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stably.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom Code

> Advanced testing flexibility with custom JavaScript implementation for Playwright code execution and dynamic value generation in Stably tests.

<Note>
  This documentation is for **Stably Classic**. For the new Stably Web Editor, see [Stably Web Editor](/stably/stably-web-editor).
</Note>

Stably provides advanced testing flexibility through custom JavaScript implementation in two primary scenarios:

1. **Playwright Code Execution**

Create custom steps or operations by directly implementing Playwright code, allowing for more complex and specialized test scenarios.

2. **Dynamic Value Generation**

Generate dynamic input values or variables programmatically using JavaScript.

<Frame>
  <img src="https://mintcdn.com/stablyai/kbD1mPIS9Ksvjr53/images/no-code-editor/custom-code.png?fit=max&auto=format&n=kbD1mPIS9Ksvjr53&q=85&s=7de09844d762803abc932f1e7a91d16b" width="1124" height="852" data-path="images/no-code-editor/custom-code.png" />
</Frame>

**Supported Libraries and Resources**

* **Faker.js:** Leverage the [Faker.js](https://fakerjs.dev/api/) library to generate realistic mock data for your tests

* **Pre-defined Variables:** Access pre-defined variables using the `VARS` object

* **Standard JavaScript Libraries:** Utilize built-in JavaScript libraries such as `Math` or `Date`