Email & Password

Email and password authentication is a common method used by many applications. Better Auth provides a built-in email and password authenticator that you can easily integrate into your project.

Enable Email and Password

To enable email and password authentication, you need to set the emailAndPassword.enabled option to true in the auth configuration.

import { betterAuth } from "better-auth";
 
export const auth = betterAuth({
  emailAndPassword: { 
    enabled: true, 
  }, 
});

Usage

Sign Up

To sign a user up, you can use the signUp.email function provided by the client.

const { data, error } = await authClient.signUp.email({
    name: "John Doe", // required
    email: "[email protected]", // required
    password: "password1234", // required
    image: "https://example.com/image.png",
    callbackURL: "https://example.com/callback",
});

Sign In

To sign a user in, you can use the signIn.email function provided by the client.

const { data, error } = await authClient.signIn.email({
    email: "[email protected]", // required
    password: "password1234", // required
    rememberMe: true,
    callbackURL: "https://example.com/callback",
});

Sign Out

To sign a user out, you can use the signOut function provided by the client.

await authClient.signOut();

you can pass fetchOptions to redirect onSuccess

await authClient.signOut({
  fetchOptions: {
    onSuccess: () => {
      router.push("/login"); // redirect to login page
    },
  },
});

Email Verification

To enable email verification, you need to pass a function that sends a verification email with a link. The sendVerificationEmail function takes a data object with the following properties:

• user: The user object.
• url: The URL to send to the user which contains the token.
• token: A verification token used to complete the email verification.

and a request object as the second parameter.

import { betterAuth } from "better-auth";
import { sendEmail } from "./email"; // your email sending function
 
export const auth = betterAuth({
  emailVerification: {
    sendVerificationEmail: async ( { user, url, token }, request) => {
      await sendEmail({
        to: user.email,
        subject: "Verify your email address",
        text: `Click the link to verify your email: ${url}`,
      });
    },
  },
});

On the client side you can use sendVerificationEmail function to send verification link to user. This will trigger the sendVerificationEmail function you provided in the auth configuration.

Once the user clicks on the link in the email, if the token is valid, the user will be redirected to the URL provided in the callbackURL parameter. If the token is invalid, the user will be redirected to the URL provided in the callbackURL parameter with an error message in the query string ?error=invalid_token.

Require Email Verification

If you enable require email verification, users must verify their email before they can log in. And every time a user tries to sign in, sendVerificationEmail is called.

export const auth = betterAuth({
  emailAndPassword: {
    requireEmailVerification: true,
  },
});

If a user tries to sign in without verifying their email, you can handle the error and show a message to the user.

await authClient.signIn.email(
  {
    email: "[email protected]",
    password: "password",
  },
  {
    onError: (ctx) => {
      // Handle the error
      if (ctx.error.status === 403) {
        alert("Please verify your email address");
      }
      //you can also show the original error message
      alert(ctx.error.message);
    },
  }
);

Triggering manually Email Verification

You can trigger the email verification manually by calling the sendVerificationEmail function.

await authClient.sendVerificationEmail({
  email: "[email protected]",
  callbackURL: "/", // The redirect URL after verification
});

Request Password Reset

To allow users to reset a password first you need to provide sendResetPassword function to the email and password authenticator. The sendResetPassword function takes a data object with the following properties:

• user: The user object.
• url: The URL to send to the user which contains the token.
• token: A verification token used to complete the password reset.

and a request object as the second parameter.

import { betterAuth } from "better-auth";
import { sendEmail } from "./email"; // your email sending function
 
export const auth = betterAuth({
  emailAndPassword: {
    enabled: true,
    sendResetPassword: async ({user, url, token}, request) => {
      await sendEmail({
        to: user.email,
        subject: "Reset your password",
        text: `Click the link to reset your password: ${url}`,
      });
    },
    onPasswordReset: async ({ user }, request) => {
      // your logic here
      console.log(`Password for user ${user.email} has been reset.`);
    },
  },
});

Additionally, you can provide an onPasswordReset callback to execute logic after a password has been successfully reset.

Once you configured your server you can call requestPasswordReset function to send reset password link to user. If the user exists, it will trigger the sendResetPassword function you provided in the auth config.

const { data, error } = await authClient.requestPasswordReset({
    email: "[email protected]", // required
    redirectTo: "https://example.com/reset-password",
});

When a user clicks on the link in the email, they will be redirected to the reset password page. You can add the reset password page to your app. Then you can use resetPassword function to reset the password. It takes an object with the following properties:

• newPassword: The new password of the user.

const { data, error } = await authClient.resetPassword({
  newPassword: "password1234",
  token,
});

const token = new URLSearchParams(window.location.search).get("token");
 
if (!token) {
  // Handle the error
}
 
const { data, error } = await authClient.resetPassword({
    newPassword: "password1234", // required
    token, // required
});

Update password

A user's password isn't stored in the user table. Instead, it's stored in the account table. To change the password of a user, you can use one of the following approaches:

const { data, error } = await authClient.changePassword({
    newPassword: "newpassword1234", // required
    currentPassword: "oldpassword1234", // required
    revokeOtherSessions: true,
});

Configuration

Password

Better Auth stores passwords inside the account table with providerId set to credential.

Password Hashing: Better Auth uses scrypt to hash passwords. The scrypt algorithm is designed to be slow and memory-intensive to make it difficult for attackers to brute force passwords. OWASP recommends using scrypt if argon2id is not available. We decided to use scrypt because it's natively supported by Node.js.

You can pass custom password hashing algorithm by setting passwordHasher option in the auth configuration.

import { betterAuth } from "better-auth"
import { scrypt } from "scrypt"
 
export const auth = betterAuth({
    //...rest of the options
    emailAndPassword: {
        password: {
            hash: // your custom password hashing function
            verify: // your custom password verification function
        }
    }
})