---
title: "Add user to group"
section: "build-a-backend/functions/examples"
platforms: ["android", "angular", "flutter", "javascript", "nextjs", "react", "react-native", "swift", "vue"]
gen: 2
last-updated: "2024-12-09T21:42:11.000Z"
url: "https://docs.amplify.aws/react/build-a-backend/functions/examples/add-user-to-group/"
---

You can use `defineAuth` and `defineFunction` to create a [Cognito post confirmation Lambda trigger](https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-lambda-post-confirmation.html) that extends the behavior to perform some action when a user is confirmed.

> **Info:** A user is "confirmed" when they verify their account. Typically this happens when the user confirms their email via the verification email. The post confirmation handler will _not_ be triggered for federated sign-ins (i.e. social sign-in).

To get started, install the AWS SDK v3 package, which will be used to perform actions against your auth resource, and the `@types/aws-lambda` package, which is used to define the handler type:

```bash title="Terminal"
npm add --save-dev @aws-sdk/client-cognito-identity-provider @types/aws-lambda
```

Next, create a new directory and a resource file, `amplify/auth/post-confirmation/resource.ts`. Then, define the Function with `defineFunction`:

```ts title="amplify/auth/post-confirmation/resource.ts"
import { defineFunction } from '@aws-amplify/backend';

export const postConfirmation = defineFunction({
  name: 'post-confirmation',
  // optionally define an environment variable for your group name
  environment: {
    GROUP_NAME: 'EVERYONE'
  },
  resourceGroupName: 'auth'
});
```

After creating the Function definition you will need to:

1. create the `EVERYONE` group
2. grant access to your auth resource to ensure it can perform the `addUserToGroup` action
3. set the Function as the post confirmation trigger

```ts title="amplify/auth/resource.ts"
import { defineAuth } from "@aws-amplify/backend";
import { postConfirmation } from "./post-confirmation/resource"

export const auth = defineAuth({
  loginWith: {
    email: true,
  },
  groups: ["EVERYONE"],
  triggers: {
    postConfirmation,
  },
  access: (allow) => [
    allow.resource(postConfirmation).to(["addUserToGroup"]),
  ],
})
```

Then create the Function's corresponding handler file, `amplify/auth/post-confirmation/handler.ts`, file with the following contents:

```ts title="amplify/auth/post-confirmation/handler.ts"
import type { PostConfirmationTriggerHandler } from 'aws-lambda';
import {
  CognitoIdentityProviderClient,
  AdminAddUserToGroupCommand
} from '@aws-sdk/client-cognito-identity-provider';
import { env } from '$amplify/env/post-confirmation';

const client = new CognitoIdentityProviderClient();

// add user to group
export const handler: PostConfirmationTriggerHandler = async (event) => {
  const command = new AdminAddUserToGroupCommand({
    GroupName: env.GROUP_NAME,
    Username: event.userName,
    UserPoolId: event.userPoolId
  });
  const response = await client.send(command);
  console.log('processed', response.$metadata.requestId);
  return event;
};
```

After deploying the changes, whenever a user signs up and verifies their account they are automatically added to the group named "EVERYONE".