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Atlas App Services

Authentication Triggers

On this page

  • Create an Authentication Trigger
  • Configuration
  • Authentication Events
  • Example
  • Additional Examples

An authentication trigger fires when a user interacts with an authentication provider. You can use authentication triggers to implement advanced user management. Some uses include:

  • Storing new user data in your linked cluster

  • Maintaining data integrity upon user deletion

  • Calling a service with a user's information when they log in.

Authentication Triggers have the following configuration options:

Trigger Type
The type of the trigger. For authentication triggers, set this value to AUTHENTICATION.
Trigger Name
The name of the trigger.
Linked Function
The name of the function that the trigger executes when it fires. An authentication event object causes the trigger to fire. This object is the only argument the trigger passes to the function.
Operation Type
The authentication operation type that causes the trigger to fire.
A list of one or more authentication provider types. The trigger only listens for authentication events produced by these providers.

Authentication events represent user interactions with an authentication provider. Each event corresponds to a single user action with one of the following operation types:

Operation Type
Represents a single instance of a user logging in.
Represents the creation of a new user.
Represents the deletion of a user.

Authentication event objects have the following form:

"operationType": <string>,
"providers": <array of strings>,
"user": <user object>,
"time": <ISODate>
The operation type of the authentication event.

The authentication providers that emitted the event.

One of the following names represents each authentication provider:

  • "anon-user"

  • "local-userpass"

  • "api-key"

  • "custom-token"

  • "custom-function"

  • "oauth2-facebook"

  • "oauth2-google"

  • "oauth2-apple"


Generally, only one authentication provider emits each event. However, you may need to delete a user linked to multiple providers. In this case, the DELETE event for that user includes all linked providers.

The user object of the user that interacted with the authentication provider.
The time at which the event occurred.

An online store wants to store custom metadata for each of its customers in Atlas. Each customer needs a document in the store.customers collection. Then, the store can record and query metadata in the customer's document.

The collection must represent each customer. To guarantee this, the store creates an Authentication Trigger. This Trigger listens for newly created users in the email/password authentication provider. Then, it passes the authentication event object to its linked function, createNewUserDocument. The function creates a new document which describes the user and their activity. The function then inserts the document into the store.customers collection.

exports = async function(authEvent) {
const mongodb ="mongodb-atlas");
const customers = mongodb.db("store").collection("customers");
const { user, time } = authEvent;
const isLinkedUser = user.identities.length > 1;
if(isLinkedUser) {
const { identities } = user;
return users.updateOne(
{ id: },
{ $set: { identities } }
} else {
return users.insertOne({ _id:, ...user })
await customers.insertOne(newUser);

For additional examples of Triggers integrated into an App Services App, checkout the example Triggers on Github.

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