with next auth I have some troubles with email clients validating the sign in links before the user clicks. Any solutions?
You're encountering a common issue with email authentication systems, including Next Auth. This problem occurs when email clients or security systems (like Microsoft's Safe Links) pre-fetch links in emails, which can invalidate one-time use tokens before the user has a chance to click them 1. Here are a couple of solutions you can implement:
- Use a two-step verification process:
Instead of sending a direct sign-in link, you can send a link to a custom page on your website. This page would contain a button that, when clicked, completes the authentication process. Here's how you could implement this:
// pages/api/auth/[...nextauth].js
import NextAuth from 'next-auth'
import EmailProvider from 'next-auth/providers/email'
export default NextAuth({
providers: [
EmailProvider({
server: process.env.EMAIL_SERVER,
from: process.env.EMAIL_FROM,
maxAge: 24 * 60 * 60, // How long email links are valid for (default 24h)
async generateVerificationToken() {
// Generate a random token
return crypto.randomBytes(32).toString('hex')
},
async sendVerificationRequest({
identifier: email,
url,
provider: { server, from },
}) {
const { host } = new URL(url)
const params = new URLSearchParams({ callbackUrl: url })
const verificationUrl = `https://${host}/auth/verify?${params}`
const emailHtml = `
<p>Please click the button below to sign in:</p>
<a href="${verificationUrl}">
<button>Sign In</button>
</a>
`
// Send the email using your email service
await sendEmail({
to: email,
from,
subject: `Sign in to ${host}`,
html: emailHtml,
})
},
}),
],
})Then, create a /auth/verify page:
// pages/auth/verify.js
import { useRouter } from 'next/router'
import { signIn } from 'next-auth/react'
export default function Verify() {
const router = useRouter()
const { callbackUrl } = router.query
const handleVerification = async () => {
await signIn('email', { callbackUrl })
}
return (
<div>
<h1>Verify Your Email</h1>
<button onClick={handleVerification}>Complete Sign In</button>
</div>
)
}- Use a short-lived token or OTP:
Instead of using a full URL, you can send a short-lived token or one-time password (OTP) in the email 2. The user would then enter this code on your website to complete the sign-in process. This approach is less likely to be affected by link prefetching.
To implement this with Next Auth, you would need to customize the EmailProvider to send an OTP instead of a link, and create a custom sign-in page where users can enter the OTP.
Both of these solutions help mitigate the issue of email clients prefetching and invalidating sign-in links. The two-step verification process is generally easier to implement and provides a good user experience, while the OTP method can be more secure but might require more custom implementation.
