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Page updated Dec 17, 2024

Sign-in

Amplify provides a client library that enables you to interact with backend resources such as Amplify Auth.

The quickest way to get started with Amplify Auth in your frontend application is with the Authenticator component, which provides a customizable UI and complete authentication flows.

Using the signIn API

import { signIn } from 'aws-amplify/auth'
await signIn({
username: "hello@mycompany.com",
password: "hunter2",
})

The signIn API response will include a nextStep property, which can be used to determine if further action is required. It may return the following next steps:

Next StepDescription
CONFIRM_SIGN_IN_WITH_NEW_PASSWORD_REQUIREDThe user was created with a temporary password and must set a new one. Complete the process with confirmSignIn.
CONFIRM_SIGN_IN_WITH_CUSTOM_CHALLENGEThe sign-in must be confirmed with a custom challenge response. Complete the process with confirmSignIn.
CONFIRM_SIGN_IN_WITH_TOTP_CODEThe sign-in must be confirmed with a TOTP code from the user. Complete the process with confirmSignIn.
CONFIRM_SIGN_IN_WITH_SMS_CODEThe sign-in must be confirmed with an SMS code from the user. Complete the process with confirmSignIn.
CONFIRM_SIGN_IN_WITH_EMAIL_CODEThe sign-in must be confirmed with an EMAIL code from the user. Complete the process with confirmSignIn.
CONFIRM_SIGN_IN_WITH_PASSWORDThe sign-in must be confirmed with the password from the user. Complete the process with confirmSignIn.
CONTINUE_SIGN_IN_WITH_FIRST_FACTOR_SELECTIONThe user must select their mode of first factor authentication. Complete the process by passing the desired mode to the challengeResponse field of confirmSignIn.
CONTINUE_SIGN_IN_WITH_MFA_SELECTIONThe user must select their mode of MFA verification before signing in. Complete the process with confirmSignIn.
CONTINUE_SIGN_IN_WITH_MFA_SETUP_SELECTIONThe user must select their mode of MFA verification to setup. Complete the process by passing either "EMAIL" or "TOTP" to confirmSignIn.
CONTINUE_SIGN_IN_WITH_TOTP_SETUPThe TOTP setup process must be continued. Complete the process with confirmSignIn.
CONTINUE_SIGN_IN_WITH_EMAIL_SETUPThe EMAIL setup process must be continued. Complete the process by passing a valid email address to confirmSignIn.
RESET_PASSWORDThe user must reset their password via resetPassword.
CONFIRM_SIGN_UPThe user hasn't completed the sign-up flow fully and must be confirmed via confirmSignUp.
DONEThe sign in process has been completed.

For more information on handling the MFA steps that may be returned, see multi-factor authentication.

Practical Example

src/App.tsx
import type { FormEvent } from "react"
import { Amplify } from "aws-amplify"
import { signIn } from "aws-amplify/auth"
import outputs from "../amplify_outputs.json"
Amplify.configure(outputs)
interface SignInFormElements extends HTMLFormControlsCollection {
email: HTMLInputElement
password: HTMLInputElement
}
interface SignInForm extends HTMLFormElement {
readonly elements: SignInFormElements
}
export default function App() {
async function handleSubmit(event: FormEvent<SignInForm>) {
event.preventDefault()
const form = event.currentTarget
// ... validate inputs
await signIn({
username: form.elements.email.value,
password: form.elements.password.value,
})
}
return (
<form onSubmit={handleSubmit}>
<label htmlFor="email">Email:</label>
<input type="text" id="email" name="email" />
<label htmlFor="password">Password:</label>
<input type="password" id="password" name="password" />
<input type="submit" />
</form>
)
}

With multi-factor auth enabled

When you have Email or SMS MFA enabled, Cognito will send messages to your users on your behalf. Email and SMS messages require that your users have email address and phone number attributes respectively. It is recommended to set these attributes as required in your user pool if you wish to use either Email MFA or SMS MFA. When these attributes are required, a user must provide these details before they can complete the sign up process.

If you have set MFA to be required and you have activated more than one authentication factor, Cognito will prompt new users to select an MFA factor they want to use. Users must have a phone number to select SMS and an email address to select email MFA.

If a user doesn't have the necessary attributes defined for any available message based MFA, Cognito will prompt them to set up TOTP.

Visit the multi-factor authentication documentation to learn more about enabling MFA on your backend auth resource.

Confirm sign-in

Following sign in, you will receive a nextStep in the sign-in result of one of the following types. Collect the user response and then pass to the confirmSignIn API to complete the sign in flow.

Next StepDescription
CONFIRM_SIGN_IN_WITH_TOTP_CODEThe sign-in must be confirmed with a TOTP code from the user. Complete the process with confirmSignIn.
CONFIRM_SIGN_IN_WITH_SMS_CODEThe sign-in must be confirmed with a SMS code from the user. Complete the process with confirmSignIn.
CONFIRM_SIGN_IN_WITH_EMAIL_CODEThe sign-in must be confirmed with a EMAIL code from the user. Complete the process with confirmSignIn.
CONFIRM_SIGN_IN_WITH_PASSWORDThe sign-in must be confirmed with the password from the user. Complete the process with confirmSignIn.
CONTINUE_SIGN_IN_WITH_FIRST_FACTOR_SELECTIONThe user must select their mode of first factor authentication. Complete the process by passing the desired mode to the challengeResponse field of confirmSignIn.
CONTINUE_SIGN_IN_WITH_MFA_SELECTIONThe user must select their mode of MFA verification before signing in. Complete the process with confirmSignIn.
CONTINUE_SIGN_IN_WITH_MFA_SETUP_SELECTIONThe user must select their mode of MFA verification to setup. Complete the process by passing either "EMAIL" or "TOTP" to confirmSignIn.
CONTINUE_SIGN_IN_WITH_TOTP_SETUPThe TOTP setup process must be continued. Complete the process with confirmSignIn.
CONTINUE_SIGN_IN_WITH_EMAIL_SETUPThe EMAIL setup process must be continued. Complete the process by passing a valid email address to confirmSignIn.
src/main.ts
import { confirmSignIn, signIn } from "aws-amplify/auth";
const { nextStep } = await signIn({
username: "hello@mycompany.com",
password: "hunter2",
});
if (
nextStep.signInStep === "CONFIRM_SIGN_IN_WITH_SMS_CODE" ||
nextStep.signInStep === "CONFIRM_SIGN_IN_WITH_EMAIL_CODE" ||
nextStep.signInStep === "CONFIRM_SIGN_IN_WITH_TOTP_CODE"
) {
// collect OTP from user
await confirmSignIn({
challengeResponse: "123456",
});
}
if (nextStep.signInStep === "CONTINUE_SIGN_IN_WITH_MFA_SELECTION") {
// present nextStep.allowedMFATypes to user
// collect user selection
await confirmSignIn({
challengeResponse: "EMAIL", // 'EMAIL', 'SMS', or 'TOTP'
});
}
if (nextStep.signInStep === "CONTINUE_SIGN_IN_WITH_MFA_SETUP_SELECTION") {
// present nextStep.allowedMFATypes to user
// collect user selection
await confirmSignIn({
challengeResponse: "EMAIL", // 'EMAIL' or 'TOTP'
});
}
if (nextStep.signInStep === "CONTINUE_SIGN_IN_WITH_EMAIL_SETUP") {
// collect email address from user
await confirmSignIn({
challengeResponse: "hello@mycompany.com",
});
}
if (nextStep.signInStep === "CONTINUE_SIGN_IN_WITH_TOTP_SETUP") {
// present nextStep.totpSetupDetails.getSetupUri() to user
// collect OTP from user
await confirmSignIn({
challengeResponse: "123456",
});
}

Sign in with an external identity provider

To sign in using an external identity provider such as Google, use the signInWithRedirect function.

import { signInWithRedirect } from "aws-amplify/auth"
signInWithRedirect({ provider: "Google" })

Note: if you do not pass an argument to signInWithRedirect it will redirect your users to the Cognito Hosted UI, which has limited support for customization.

Alternatively if you have configured OIDC or SAML-based identity providers in your auth resource, you can specify a "custom" provider in signInWithRedirect:

import { signInWithRedirect } from "aws-amplify/auth"
signInWithRedirect({ provider: {
custom: "MyOidcProvider"
}})

Auto sign-in

The autoSignIn API will automatically sign-in a user when it was previously enabled by the signUp API and after any of the following cases has completed:

  • User confirmed their account with a verification code sent to their phone or email (default option).
  • User confirmed their account with a verification link sent to their phone or email. In order to enable this option you need to go to the Amazon Cognito console, look for your userpool, then go to the Messaging tab and enable link mode inside the Verification message option. Finally you need to define the signUpVerificationMethod to link inside the Cognito option of your Auth config.
src/main.ts
import { autoSignIn } from 'aws-amplify/auth';
await autoSignIn();

Note: When MFA is enabled, your users may be presented with multiple consecutive steps that require them to enter an OTP to proceed with the sign up and subsequent sign in flow. This requirement is not present when using the USER_AUTH flow.

Sign in with passwordless methods

Your application's users can also sign in using passwordless methods. To learn more, visit the concepts page for passwordless.

SMS OTP

Pass SMS_OTP as the preferredChallenge when calling the signIn API in order to initiate a passwordless authentication flow with SMS OTP.

const { nextStep: signInNextStep } = await signIn({
username: '+15551234567',
options: {
authFlowType: 'USER_AUTH',
preferredChallenge: 'SMS_OTP',
},
});
if (signInNextStep.signInStep === 'CONFIRM_SIGN_IN_WITH_SMS_CODE') {
// prompt user for otp code delivered via SMS
const { nextStep: confirmSignInNextStep } = await confirmSignIn({
challengeResponse: '123456',
});
if (confirmSignInNextStep.signInStep === 'DONE') {
console.log('Sign in successful!');
}
}

Email OTP

Pass EMAIL_OTP as the preferredChallenge when calling the signIn API in order to initiate a passwordless authentication flow using email OTP.

const { nextStep: signInNextStep } = await signIn({
username: 'hello@example.com',
options: {
authFlowType: 'USER_AUTH',
preferredChallenge: 'EMAIL_OTP',
},
});
if (signInNextStep.signInStep === 'CONFIRM_SIGN_IN_WITH_EMAIL_CODE') {
// prompt user for otp code delivered via email
const { nextStep: confirmSignInNextStep } = await confirmSignIn({
challengeResponse: '123456',
});
if (confirmSignInNextStep.signInStep === 'DONE') {
console.log('Sign in successful!');
}
}

WebAuthn Passkeys

Pass WEB_AUTHN as the preferredChallenge in order to initiate the passwordless authentication flow using a WebAuthn credential.

const { nextStep: signInNextStep } = await signIn({
username: 'hello@example.com',
options: {
authFlowType: 'USER_AUTH',
preferredChallenge: 'WEB_AUTHN',
},
});
if (signInNextStep.signInStep === 'DONE') {
console.log('Sign in successful!');
}

Password

Pass either PASSWORD or PASSWORD_SRP as the preferredChallenge in order to initiate a traditional password based authentication flow.

const { nextStep: signInNextStep } = await signIn({
username: 'hello@example.com',
password: 'example-password',
options: {
authFlowType: 'USER_AUTH',
preferredChallenge: 'PASSWORD_SRP', // or 'PASSWORD'
},
});
if (confirmSignInNextStep.signInStep === 'DONE') {
console.log('Sign in successful!');
}

First Factor Selection

Omit the preferredChallenge parameter to discover what first factors are available for a given user.

The confirmSignIn API can then be used to select a challenge and initiate the associated authentication flow.

const { nextStep: signInNextStep } = await signIn({
username: '+15551234567',
options: {
authFlowType: 'USER_AUTH',
},
});
if (
signInNextStep.signInStep === 'CONTINUE_SIGN_IN_WITH_FIRST_FACTOR_SELECTION'
) {
// present user with list of available challenges
console.log(`Available Challenges: ${signInNextStep.availableChallenges}`);
// respond with user selection using `confirmSignIn` API
const { nextStep: nextConfirmSignInStep } = await confirmSignIn({
challengeResponse: 'SMS_OTP', // or 'EMAIL_OTP', 'WEB_AUTHN', 'PASSWORD', 'PASSWORD_SRP'
});
}