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Better Auth is a framework-agnostic authentication library for TypeScript. It relies on transactional email for password resets, email verification, magic links, and one-time codes, all of which you can deliver with Resend.

Prerequisites

Before you start, you’ll need:

A Resend API key
A verified domain
A project with Better Auth installed

Install the Resend SDK

npm install resend

pnpm add resend

yarn add resend

Add your API key to the environment:

.env

RESEND_API_KEY=re_xxxxxxxxx

The hook examples below call void resend.emails.send(...) instead of awaiting it, as Better Auth recommends, so the response time doesn’t reveal whether an account exists. On serverless platforms, wrap the send in waitUntil (or your platform’s equivalent) so the function doesn’t terminate before the email is sent.

Send password reset and verification emails

Better Auth calls your sendResetPassword and sendVerificationEmail hooks when a user requests a reset or needs to confirm their address. Send the email with Resend inside each hook.

auth.ts

import { betterAuth } from 'better-auth';
import { Resend } from 'resend';

const resend = new Resend(process.env.RESEND_API_KEY);

export const auth = betterAuth({
  emailAndPassword: {
    enabled: true,
    sendResetPassword: ({ user, url }) => {
      void resend.emails.send({
        from: 'Acme <onboarding@example.com>',
        to: user.email,
        subject: 'Reset your password',
        html: `Click <a href="${url}">here</a> to reset your password.`,
      });
    },
  },
  emailVerification: {
    sendVerificationEmail: ({ user, url }) => {
      void resend.emails.send({
        from: 'Acme <onboarding@example.com>',
        to: user.email,
        subject: 'Verify your email address',
        html: `Click <a href="${url}">here</a> to verify your email.`,
      });
    },
  },
});

Set the from address to match your verified domain.

Send magic links (optional)

If you use the magic link plugin, send the sign-in link through the sendMagicLink hook.

auth.ts

import { betterAuth } from 'better-auth';
import { magicLink } from 'better-auth/plugins';
import { Resend } from 'resend';

const resend = new Resend(process.env.RESEND_API_KEY);

export const auth = betterAuth({
  plugins: [
    magicLink({
      sendMagicLink: ({ email, url }) => {
        void resend.emails.send({
          from: 'Acme <onboarding@example.com>',
          to: email,
          subject: 'Sign in to Acme',
          html: `Click <a href="${url}">here</a> to sign in.`,
        });
      },
    }),
  ],
});

Set the from address to match your verified domain.

Send one-time codes (optional)

The email OTP plugin sends a one-time password (OTP), a numeric code, instead of a link. The type argument tells you which flow triggered the request so you can tailor the subject line.

auth.ts

import { betterAuth } from 'better-auth';
import { emailOTP } from 'better-auth/plugins';
import { Resend } from 'resend';

const resend = new Resend(process.env.RESEND_API_KEY);

export const auth = betterAuth({
  plugins: [
    emailOTP({
      sendVerificationOTP: ({ email, otp, type }) => {
        void resend.emails.send({
          from: 'Acme <onboarding@example.com>',
          to: email,
          subject:
            type === 'sign-in' ? 'Your sign-in code' : 'Your verification code',
          html: `Your code is <strong>${otp}</strong>.`,
        });
      },
    }),
  ],
});

Set the from address to match your verified domain.

Customize email templates

For richer, reusable emails, author your templates with React Email and pass the rendered component to Resend’s react field, or reference a Resend template by id.

auth.ts

import { ResetPasswordEmail } from './emails/reset-password';

sendResetPassword: ({ user, url }) => {
  void resend.emails.send({
    from: 'Acme <onboarding@example.com>',
    to: user.email,
    subject: 'Reset your password',
    react: ResetPasswordEmail({ url }),
  });
},

Set the from address to match your verified domain.

Debugging email delivery

When a flow doesn’t behave as expected, check both sides:

Better Auth logs show the hook invocation and any errors thrown while sending.
Resend Logs show the delivery side: accepted, delivered, opened, bounced.

Together, you get end-to-end visibility across the entire delivery chain.

Sunbelt Computer Software

PL/B Language Development and Support

Get started

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Resources

Send Better Auth emails with Resend

Prerequisites

Install the Resend SDK

Send password reset and verification emails

Send magic links (optional)

Send one-time codes (optional)

Customize email templates

Debugging email delivery

Sunbelt Computer Software

PL/B Language Development and Support

​Prerequisites

​Install the Resend SDK

​Send password reset and verification emails

​Send magic links (optional)

​Send one-time codes (optional)

​Customize email templates

​Debugging email delivery

Prerequisites

Install the Resend SDK

Send password reset and verification emails

Send magic links (optional)

Send one-time codes (optional)

Customize email templates

Debugging email delivery