# Create applications
URL: https://docs.datarobot.com/en/docs/classic-ui/app-builder/create-app.html

> Create No-Code AI Apps to enable core DataRobot services while using a no-code interface.

# Create applications

You can create applications in DataRobot from the [Applications](https://docs.datarobot.com/en/docs/classic-ui/app-builder/create-app.html#from-the-applications-tab) tab, a [model on the Leaderboard](https://docs.datarobot.com/en/docs/classic-ui/app-builder/create-app.html#from-the-leaderboard), or a [deployment](https://docs.datarobot.com/en/docs/classic-ui/app-builder/create-app.html#from-a-deployment). If you're creating an application from a time series deployment, see the documentation for [time series applications](https://docs.datarobot.com/en/docs/classic-ui/app-builder/ts-app.html).

> [!NOTE] Multiclass projects with over 1000 classes
> For [unlimited multiclass](https://docs.datarobot.com/en/docs/classic-ui/modeling/analyze-models/evaluate/multiclass.html#unlimited-multiclass) projects with more than 1000 classes, by default, DataRobot keeps the top 999 most frequent classes and aggregates the remainder into a single "other" bucket. You can, however, configure the aggregation parameters to ensure all classes necessary to your project are represented.

> [!NOTE] Note
> You can create multiple applications from the same deployment.

## Template options

Before creating an application, consider the purpose of the app and review the template options—Predictor, What-if, or Optimizer—and if the deployment you intend to use is time series or non-time series.  While templates only determine the initial configuration of the application and selecting a template does not mean the app can only be used for that purpose, time series applications require additional setup. See the documentation for [time series applications](https://docs.datarobot.com/en/docs/classic-ui/app-builder/ts-app.html).

The table below describes each template option:

| Template | Description | Default configuration | Time series |
| --- | --- | --- | --- |
| Predictor | Makes predictions for a target feature based on the information provided when the app is created and deployed. | Hides the What-if and Optimizer widget. | ✔ |
| What-if | Creates and compares multiple prediction scenarios side-by-side to determine the option with the best outcome. | Displays the What-if and Optimizer widget with only the what-if functionality enabled. | ✔ |
| Optimizer | Runs simulations to optimize an outcome for a given goal. This is most effective when you want to optimize for a single row. | Displays the What-if and Optimizer widget with only the optimizer functionality enabled.The All Rows widget displays an Optimized Prediction column. |  |

## From the Applications tab

When creating an application from the Applications tab, DataRobot uses an active deployment as the basis of the app. To create an application from the Applications tab:

1. Navigate to theApplicationstab.
2. The available application templates are listed at the top of the page. ClickUse templatenext to the template best suited for your use case.
3. A dialog box appears, prompting you to name the application and choose asharing option—Anyone With the Sharing Linkautomatically generates a link that can be shared with non-DataRobot users whileInvited Users Onlylimits sharing to other DataRobot users, groups, and organizations. The access option determines the initial configuration of the sharing permissions, which can be changed in theapplication settings.
4. ClickNext: select deployment.
5. Select a deployment for the application and clickCreate. Note that you must be an owner of the deployment in order to launch an application from it. You are then taken to theApplicationstab while the application builds.

## From the Leaderboard

To create an application from a specific model on the Leaderboard:

1. After your models are built, navigate to theLeaderboardand select the model you want to use to build an application.
2. Click theBuild apptab and select the appropriate template for your use case.
3. Name the application and select asharing optionfrom the dropdown. ClickCreatewhen you're done.
4. The new application appears on theLeaderboardbelow the model's app templates as well as on theApplicationstab.

## From a deployment

To create an application from a deployed model:

1. Navigate to theDeploymentinventory and select the deployment you want to launch the application from.
2. SelectCreate applicationfrom the action menu of your desired deployment.
3. Select the application template you would like to use and clickNext: add app info.
4. Name the application and choose asharing optionfrom the dropdown. When you're done, clickCreate.

The application is available for use on the Applications tab.

### Deployments with an association ID

When creating an application from a deployment with an association ID, note the following:

- Accuracy and data drift are tracked for all single and batch predictions made using the application.
- Accuracy and data drift are not tracked for synthetic predictions (simulations) made in the application using the What-If and Optimizer widget.
- You cannot add an association ID to deployments that have already been used to create an application.

In the deployment Settings, [add an association ID](https://docs.datarobot.com/en/docs/classic-ui/mlops/deployment-settings/accuracy-settings.html#select-an-association-id). If Require association ID in prediction requests is enabled, this setting cannot be disabled after the application is created.

If an application is created from a deployment with an association ID, the association ID is added as a required field to make single predictions in the application. This field cannot be removed in Build mode.

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