Create a Realm App (Realm UI)

The following steps guide you through setting up a generic Realm app. The term "Realm app" refers to the central MongoDB Realm backend instance for your mobile or web application.

Before you begin, you will need a MongoDB Atlas account. You can learn more about creating an Atlas account in the Atlas Getting Started documentation.

To use MongoDB Realm, you must be logged into Atlas.

To create an Atlas cluster to use with your Realm app, following these steps:

  1. In the left navigation menu, click Clusters, and then click the Build New Cluster button. The Create New Cluster page opens.
  2. Choose your preferred provider and region, tier, and additional settings. As you build your cluster, Atlas displays the associated costs at the bottom of the page.

    Be sure to select MongoDB version 4.4 for your cluster if you wish to use sync!


    Atlas provides a Free Tier M0 replica set as well as paid M10+ clusters. Free Tier deployments have restrictions as compared to paid M10+ deployments but will work for the purposes of the tutorials we offer. For complete documentation on these restrictions, see Atlas M0 (Free Tier), M2, and M5 Limitations.

  3. The default cluster name is Cluster0. If you wish to change the name, do so now, as cluster names cannot be changed once configured.
  4. Click the Create Cluster button to save your changes.

For detailed information about the options available when creating an Atlas cluster, see Create a New Cluster.

  1. In Atlas, select the Realm tab.
  2. If you are creating your first Realm app in this Atlas project, click the Start a New Realm App button in the center of the screen. If you have already created at least one Realm app in this Atlas project, click the Create a New App button in the top right of the screen.
  3. In the Name your Realm application dialog, enter an Application Name for your Realm app.

    App Name Limitations

    Application names must be between 1 and 32 characters and may only contain ASCII letters, numbers, underscores, and hyphens.

  4. Select a cluster in your project in your project from the Link your Database dropdown. MongoDB Realm will automatically create a MongoDB service linked to this cluster with the name "mongodb-atlas".

    MongoDB Version 4.4 Required

    In order to use Realm Sync, your Atlas cluster must use MongoDB version 4.4. When setting up your cluster, select MongoDB 4.4 from the dropdown menu under Additional Settings.

  5. Select a deployment model and deployment region for your application.
  6. Click Create Realm Application.
The app creation modal in the UI

Upon creation of your Realm app, you will be redirected to the MongoDB Realm console. Your Realm app is created with a MongoDB service named mongodb-atlas.

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