> Markdown version of [IntelliJ IDEA](https://vaadin.com/docs/next/getting-started/dev-environment/run/intellij). Section index: [llms.txt](https://vaadin.com/docs/next/getting-started/llms.txt)

# Run in IntelliJ IDEA

You can run and debug your Vaadin application in IntelliJ IDEA as you would any other Java application. When you imported the project into IntelliJ IDEA, a run/debug configuration called *Application* should have been created automatically. You can start the application by clicking the **Debug** button in the toolbar. It is indicated by a red circle in this screenshot:

[Image: Debug button in IntelliJ IDEA]

The application starts up and you can access it at <http://localhost:8080>. Changes to stylesheets are applied to the browser automatically. However, to enable Java hotswap, you have to take some additional actions.

## <a id="gradle-projects"></a>Gradle Projects

By default, IntelliJ IDEA delegates build and run actions to Gradle for Gradle-based projects. For a better development experience, configure IntelliJ IDEA to build and run using its own compiler instead:

1. Go to **Settings** > **Build, Execution, Deployment** > **Build Tools** > **Gradle**.

2. Under **Build and run using**, select **IntelliJ IDEA**.

3. Under **Run tests using**, select **IntelliJ IDEA**.

This avoids unnecessary Gradle task execution during development and provides faster compilation.

> **Tip:** When using hot deploy with Gradle, ensure that `frontendHotdeploy` is set to `true` in the `vaadin {}` block in `build.gradle`, not only in `application.properties`. The Gradle plugin does not read `application.properties`. See [Vaadin Plugin Configuration](https://vaadin.com/docs/next/flow/configuration/gradle.md#build-file.vaadin-options) for details. This is only needed if you explicitly run the `vaadinPrepareFrontend` task. (since undefined)

## <a id="enabling-hotswap"></a>Enabling Hotswap

The easiest way of running a Vaadin application with hotswap in IntelliJ IDEA is by installing the [Vaadin plugin](https://plugins.jetbrains.com/plugin/23758-vaadin). If you haven’t done so already, do it now.

Click on the button with three small dots next to the run/debug configuration. It is highlighted on this screenshot with a red circle:

[Image: IntelliJ IDEA with a generated skeleton]

This brings up a menu that looks like this:

[Image: The more actions menu in IntelliJ IDEA]

Start the application by selecting **Debug using HotswapAgent**. If you can’t see this option, the Vaadin plugin has not been installed correctly.

If the run/debug configuration was not automatically created, you can start the application in another way. Look up the main application class and right-click it in the project navigator. Then click **More Run/Debug** **›** **Debug using HotswapAgent**, as shown on this screenshot:

[Image: IntelliJ IDEA context menu]

Your application now starts up with hotswap of Java classes enabled. Open the application in a browser and verify that everything is working through Vaadin Copilot. Move your mouse pointer over the **Copilot** button at the bottom-right corner:

[Image: Vaadin Copilot menu visible in a browser]

> **Important:** The Copilot button is only available when the application is running in development mode. It is not available in production mode.

Now click **Development workflow**. You can see that both the IntelliJ IDEA plugin and hotswap are working correctly:

[Image: Vaadin Copilot development workflow dialog]