Before we can implement any client SDK functionality for the Task Tracker, we need to create a backend Realm app to serve SDK requests like authentication and Realm Sync. To make this easier and faster, we've already prepared a backend Realm app configuration for you, complete with functions, triggers, a schema, and the Realm Sync configuration you'll need to connect with one of our front-end tutorial apps.
Prefer to learn by watching? Follow along while we set up the backend in this video tutorial walk-through!
To use our pre-made backend, you'll have to:
- Create an Atlas account, if you don't already have one. (3 minutes)
- Create a free Atlas cluster running MongoDB 4.4 or higher. (5 minutes)
- Install the Realm CLI. (5 minutes)
- Add a programmatic API key to your Atlas project and use it to log into the Realm CLI. (5 minutes)
- Use the Realm CLI to create a new Task Tracker backend Realm app with our pre-made Task Tracker backend. (5 minutes)
Time estimate: 3 minutes
To begin, you'll need a MongoDB Atlas account. If you've already got an existing MongoDB Atlas Account, you can proceed to the next step. If you don't have an Atlas account, follow the steps below to create one:
1. Navigate to the MongoDB Atlas login page.
- Click Login.
- Either enter a new set of user credentials or click the Sign Up with Google button.
- Click Sign Up to create your account.
Follow the prompts to create an organization and project in your Atlas account. You can use the default suggested names or enter your own.
When you finish creating your organization and project, you should end up on a screen that prompts you to create an Atlas cluster:
For additional details on how to create an account, see Create an Atlas Account.
Time estimate: 5 minutes
In order to use Realm Sync, your Atlas cluster must use MongoDB version 4.4 or higher. When setting up your cluster, select MongoDB 4.4 (or a higher version) from the dropdown menu under Additional Settings.
Next, you'll need an MongoDB Atlas cluster running MongoDB 4.4 or higher. If you've already created a free cluster in your Atlas project running a version of MongoDB lower than 4.4, you can create a new project in Atlas and then create a new cluster running MongoDB 4.4 or higher in that project using the instructions below. If you haven't created any clusters yet, follow the instructions below to create your first free cluster:
- Log into your MongoDB Atlas account at cloud.mongodb.com.
Once you're logged into your account, Atlas should prompt you to create your first cluster. In the Shared Clusters category, click Create a Cluster. Alternatively, you can click Build a Cluster from the project view in your Atlas account.
- Under Cloud Provider & Region, select AWS and N. Virginia (us-east-1).
- Under Additional Settings, select MongoDB 4.4 (or a higher version) from the Select a Version dropdown.
- Under Cluster Name, enter the name
Cluster0for your new cluster.
- Click the Create Cluster button at the bottom of the page.
After creating your cluster, Atlas should launch the project view for your Atlas account. In this view, you'll see Atlas's progress as it initializes your new cluster:
For additional details on how to create a MongoDB Atlas cluster, see Deploy a Free Tier Cluster.
Time estimate: 5 minutes
Now that you've created a cluster to use as the data source for your
Realm app, we need some way to create the app itself. In most cases you'd
use the Realm UI, which you can access through the Atlas UI. However,
for the purposes of this tutorial, we're going to use the Realm
Command Line Interface, also known as
We're using the Realm CLI because
realm-cli allows you to manage
your Realm apps programmatically using JSON configuration files instead of
the Realm UI. This lets you get started with a pre-prepared
app configuration faster. Follow the instructions below to install
the Realm CLI in your development environment using either a package
manager or the
Realm CLI is available on
npm. To install it on your system, ensure that you
have Node.js installed and then run the
following command in your shell:
npm install -g mongodb-realm-cli
This tutorial is compatible with version 2 of
realm-cli. If you already
have the CLI installed, check your version to make sure that it's compatible
with this tutorial.
Time estimate: 5 minutes
Now that you've got
realm-cli installed to your development
environment, you'll need a way to authenticate using
For security reasons,
realm-cli only allows login using a
programmatic API key, so we'll begin by creating a programmatic API Key
that you can use to administrate your new Atlas project:
- Click Access Manager at the top of the Atlas UI. Select the Project Access option from the dropdown.
- Navigate to the API Keys tab.
- Click the Create API Key button.
In the Description text box, enter "API Key for the MongoDB Realm CLI".
In the Project Permissions dropdown, select "Project Owner" and deselect "Project Read Only".
- Click Next.
- Copy your Public API Key and save it somewhere.
- Copy your Private API Key and save it somewhere; after leaving this page, you will no longer be able to view it via the Realm UI.
- Click the Add Access List Entry button.
- Click Use Current IP Address.
- Click Save.
- When you have safely recorded your private API key, click Done to navigate back to the Project Access Manager page.
Use the following command in your terminal to authenticate with the Realm CLI:
realm-cli login --api-key <public API key> --private-api-key <private API key>
realm-cli produces output like the following, you have
Successfully logged in
For additional details about how to create a programmatic API key in MongoDB Atlas, see the documentation for configuring API access.
For additional details about authenticating using a programmatic API
realm-cli, see the Realm CLI authentication guide.
Time estimate: 5 minutes
Now that you've got an Atlas account, an Atlas cluster running MongoDB
4.4 or higher, and an authenticated
realm-cli session, you're ready to fetch
the Task Tracker backend configuration. Begin by downloading the
realm-tutorial-backend github repository using the
Run the following command to download the pre-made Task Tracker backend configuration:
git clone https://github.com/mongodb-university/realm-tutorial-backend.git
You should see output like the following:
Cloning into 'realm-tutorial-backend'... remote: Enumerating objects: 39, done. remote: Counting objects: 100% (39/39), done. remote: Compressing objects: 100% (31/31), done. remote: Total 39 (delta 3), reused 39 (delta 3), pack-reused 0 Receiving objects: 100% (39/39), 7.25 KiB | 1.81 MiB/s, done. Resolving deltas: 100% (3/3), done.
The directory where you ran the above
git clonecommand should now contain another directory called
realm-tutorial-backend. We'll use the contents of that directory to create your very own Task Tracker Realm app backend with the Realm CLI.ImportantRealm CLI Version Compatibility
If you're using version 1 of
realm-clithen you will need to use a different branch that contains compatible configuration files:
git checkout -b final-v1 origin/final-v1
Navigate into the root directory of the
realm-clito create your app.
realm-climay take a few seconds to query your Atlas project, but you should soon see the following output:
Do you wish to create a new app? [y/n]
Press "y", then press ENTER to confirm your intention to create a new app.
realm-cliwill prompt you for the following details:
App name [tasktracker]: App Location App Deployment Model App Environment
Press ENTER at each prompt to use the default value for your app configuration.
- Press "y", then press ENTER to confirm the values for the app configuration
You should see the following output if your push command successfully created a new app:
Successfully pushed app up
You can confirm that your app was created successfully by
navigating to the Realm tab in the Atlas UI. You should
see a Realm app named
To understand the purpose of the files in the backend app repo, see Realm Application Configuration.
Time estimate: 5 minutes
Now that you've successfully created your application, it's time to
explore the provided configuration. You can access your app by
navigating to the Realm tab in the Atlas UI. Click on the
card representing the
tasktracker app to launch the Realm UI for
managing the Task Tracker backend.
Now that we can view the configuration of our app in the Realm UI, we
can take a look at all of the configuration uploaded from the JSON in
realm-tutorial-backend. If you'd rather jump straight into a client
SDK guides, you can find the links in the
What's Next? section below.
The Schema section of the Realm UI displays information
about the structure of the data stored in our linked Atlas cluster.
In this section, you should see a cluster called
that contains two collections: Task and User. You can navigate to the
Schema tab to view the JSON Schema that defines the structure of the
data in each collection.
While MongoDB's document model allows us to store data in a wide variety of shapes and sizes, Realm Database and Realm Sync require data to follow a set schema. Data that follows this schema synchronizes between the MongoDB Atlas linked data source and devices connected to your Realm app via a client SDK. This schema should match the models defined in client applications, with minor exceptions.
In the Authentication Providers tab of the Authentication section, you'll find information about the different ways that users can log into the Task Tracker app. In the provided Task Tracker configuration, users can only log in via "Email/Password" authentication, which lets users define an email username and a secret password known only to them to access their account in your Realm app.
If you click on the Email/Password entry in the list of authentication providers, you can view the details of Task Tracker's Email/Password authentication configuration. There are a few important fields here:
- User Confirmation Method: we've selected "automatically confirm users" so that users can log in immediately after creating an account. In a production application, you might prefer to "send a confirmation email" so that users can confirm ownership of their email accounts.
- Password Reset Method: we've selected "run a password reset function",
resetFuncdoesn't actually implement any logic: it always fails. For a production application, you'd want to implement a function that actually resets the user's password if they forget it.
To learn more about authentication in MongoDB Realm, see the documentation on Authentication.
In the Sync section, you'll find information about Realm Sync,
which synchronizes data between client devices and your MongoDB Atlas
cluster. To enable sync, we've defined a partition key, which
sorts the data in Atlas into multiple realms.
We've chosen an easy-to-understand name for our partition key:
_partition. Task Tracker also defines permissions for Realm Sync,
which determine what partitions each user can access. Click the
Define Permissions dropdown to view the permission
definitions, which call the
canWritePartition functions to determine whether a user can read or
write a particular realm.
To learn more about Realm Sync, see Realm Sync Overview.
In MongoDB Realm, each user can have an associated custom data object. We designed this app to use data stored in the user's custom data to determine permissions -- that is, whether that user can read or write a given realm or set of data, such as a project. While Realm allows clients to read and write data depending on how you configure your app permissions, we configured this app so that only system functions running on the backend can modify a user's custom data object. This prevents clients from arbitrarily granting themselves permissions.
To learn more about custom user data, see Enable Custom User Data.
The Functions section contains the Task Tracker app's executable backend logic. This includes functions that:
- add a team member to a user's project
- determine whether or not a user can read a particular partition
- determine whether or not a user can write to a particular partition
- create a new user document in the synced Atlas cluster
- fetch the members of a user's project
- remove a team member from a user's project
- reset a user's password (unimplemented)
To learn more about functions in MongoDB Realm, see the documentation on functions.
In the Triggers section, you'll find information about
triggers, certain criteria that, when met, execute logic in the
Task Tracker backend via a function. In Task Tracker, you'll find one
onNewUser. Click on the trigger to see details about the
type of trigger and the function that that trigger activates.
onNewUser has just one purpose: when a new user creates an account
(hence the "Create" action type and the "Authentication" trigger type),
onNewUser calls the
createNewUserDocument function which
initializes the custom user data for that user. This provides the first
data needed to create that user's personal project, and allows them to
start adding to-do tasks or even other users as project members.
To learn more about triggers in MongoDB Realm, see the documentation on triggers.
You just built a functional task tracker application backend with MongoDB Realm. Great job!
Now that you have a working Realm application, you can follow one of our client application tutorials to connect to your Realm app and manage tasks from a mobile or web application.