# Custom model in a DataRobot environment
URL: https://docs.datarobot.com/en/docs/classic-ui/mlops/deployment/deploy-workflows/cus-model-dr-env.html

> How to deploy a custom model in a DataRobot prediction environment.

# Deploy a custom model in a DataRobot Environment

Custom inference models allow you to bring your pre-trained models into DataRobot. To deploy a custom model to a DataRobot prediction environment, you can create a custom model in the Custom Model Workshop. Then, you can prepare, test, and register that model, and deploy it to a centralized deployment hub where you can monitor, manage, and govern it alongside your deployed DataRobot models. DataRobot supports custom models built in various programming languages, including Python, R, and Java.

To create and deploy a custom model in DataRobot, follow the workflow outlined below:

```
graph TB
  A[Create a custom model] --> B{Use a custom model environment?} 
  B --> |Yes|C[Create a custom model environment]
  B --> |No|D[Prepare the custom model];
  C --> D
  D --> E{Test locally?}
  E --> |No|H[Test the custom model in DataRobot]
  E --> |Yes|F[Install the DataRobot Model Runner]
  F --> G[Test the custom model locally]
  G --> H
  H --> I[Register the custom model]
  I --> J[Deploy the custom model]
```

## Create a custom model

Custom inference models are user-created, pre-trained models (made up of a collection of files) uploaded to DataRobot via the Custom Model Workshop.

You can assemble custom inference models in either of the following ways:

- Create a custom modelwithoutproviding the model requirements andstart_server.shfile on theAssembletab. This type of custom modelmustuse a drop-in environment. Drop-in environments contain the requirements andstart_server.shfile used by the model. They areprovided by DataRobotin the Custom Model Workshop. You can alsocreate your owndrop-in custom environment.
- Create a custom modelwiththe model requirements andstart_server.shfile on theAssembletab. This type of custom model can be paired with acustomordrop-inenvironment.

[Create a custom model](https://docs.datarobot.com/en/docs/classic-ui/mlops/deployment/custom-models/custom-model-workshop/custom-inf-model.html)

### (Optional) Create a custom model environment

If you decide to use a custom environment or a custom drop-in environment, you must create that environment in the Custom Model Workshop. You can reuse these environments for other custom models.

You can assemble custom model environments in either of the following ways:

- Create a custom drop-in environmentwiththe model requirements andstart_server.shfile for the model. DataRobot provides severaldefault drop-in environmentsin the Custom Model Workshop.
- Create a custom environmentwithoutthe model requirements andstart_server.shfile. Instead, you must provide the requirements and astart_server.shfile in the model folder for the custom model you intend to use with this environment.

[Create a custom model environment](https://docs.datarobot.com/en/docs/classic-ui/mlops/deployment/custom-models/custom-model-environments/custom-environments.html)

## Prepare the custom model

Before adding custom models and environments to DataRobot, you must prepare and structure the files required to run them successfully. The tools and templates necessary to prepare custom models are hosted in the [DataRobot User Models GitHub Repository](https://github.com/datarobot/datarobot-user-models) (Log in to GitHub before clicking this link.). Once you verify the model's files and folder structure, you can proceed to test the model.

[Prepare a custom model](https://docs.datarobot.com/en/docs/api/code-first-tools/drum/index.html)

### (Optional) Test locally

The [DataRobot Model Runner](https://pypi.org/project/datarobot-drum/) is a tool you can use to work locally with Python, R, and Java custom models. It can verify that a custom model can run and make predictions before you add it to DataRobot. However, this testing is only for development purposes, and DataRobot recommends that you use the Custom Model Workshop to test any model you intend to deploy.

[Test a custom model locally](https://docs.datarobot.com/en/docs/api/code-first-tools/drum/custom-local-test.html)

### Test in DataRobot

Testing the custom model in the Custom Model Workshop ensures that the model is functional before deployment. These tests use the model environment to run the model and make predictions with test data.

> [!NOTE] Note
> While you can deploy your custom inference model without testing, DataRobot strongly recommends that you ensure your model passes testing in the Custom Model Workshop before deployment.

[Test a custom model in DataRobot](https://docs.datarobot.com/en/docs/classic-ui/mlops/deployment/custom-models/custom-model-workshop/custom-model-test.html)

## Register the custom model

After successfully creating and testing a custom inference model in the Custom Model Workshop, you can add it to the Model Registry as a deployment-ready model package.

[Register a custom model](https://docs.datarobot.com/en/docs/classic-ui/mlops/deployment/custom-models/custom-model-workshop/custom-model-reg.html)

## Deploy the custom model

After you register a custom inference model in the Model Registry, you can deploy it. Deployed custom models make predictions using API calls to a dedicated prediction server managed by DataRobot.

[Deploy a custom model](https://docs.datarobot.com/en/docs/classic-ui/mlops/deployment/deploy-methods/deploy-custom-inf-model.html).

---
