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Page updated May 3, 2024


Amplify Auth's behavior can be customized through the use of triggers. A trigger is defined as a Function, and is a mechanism to slot some logic to execute during the authentication flow. For example, you can use triggers to validate whether emails include an allowlisted domain, add a user to a group upon confirmation, or create a "UserProfile" model upon account confirmation.

Triggers translate to Cognito user pool Lambda triggers.

When you have a Lambda trigger assigned to your user pool, Amazon Cognito interrupts its default flow to request information from your function. Amazon Cognito generates a JSON event and passes it to your function. The event contains information about your user's request to create a user account, sign in, reset a password, or update an attribute. Your function then has an opportunity to take action, or to send the event back unmodified.

To get started, define a function and specify the triggers property on your auth resource:

import { defineAuth } from "@aws-amplify/backend"
export const auth = defineAuth({
loginWith: {
email: true,
triggers: {}

To learn more about use cases for triggers, visit the Functions examples.