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Build a custom flow for handling email links

Warning

This guide is for users who want to build a custom user interface using the Clerk API. To use a prebuilt UI, use the Account Portal pages or prebuilt components.

Email links can be used to sign up new users, sign in existing users, or allow existing users to verify newly added email addresses to their user profiles.

The email link flow works as follows:

  1. The user enters their email address and asks for an email link.
  2. Clerk sends an email to the user, containing a link to the verification URL.
  3. The user visits the email link, either on the same device where they entered their email address or on a different device, depending on the settings in the Clerk Dashboard.
  4. Clerk verifies the user's identity and advances any sign-up or sign-in attempt that might be in progress.
  5. If the verification is successful, the user is authenticated or their email address is verified, depending on the reason for the email link.

This guide demonstrates how to use Clerk's API to build a custom flow for handling email links. It covers the following scenarios:

To allow your users to sign up or sign in using email links, you must first configure the appropriate settings in the Clerk Dashboard.

  1. In the Clerk Dashboard, navigate to the Email, phone, username page.
  2. For this guide, ensure that only Email address is required. If Phone number, Username, or Name are enabled, ensure they are not required. Use the settings icon next to each option to verify if it's required or optional. If you would like to require any of these, you'll need to combine their custom flows with the email link custom flow.
  3. In the Authentication strategies section, ensure only Email verification link is enabled. By default, Require the same device and browser is enabled, which means that email links are required to be verified from the same device and browser on which the sign-up or sign-in was initiated. For this guide, leave this setting enabled.
  4. Keep this page open to enable email link verification in the next step.

Verification methods are different from authentication strategies. Authentication strategies are used for authenticating a user, such as when they are signing in to your application. Verification methods are used for verifying a user's identifier, such as an email address upon initial sign-up or when adding a new email to their account.

To allow your users to verify their email addresses using email links, configure the following settings:

  1. On the Email, phone, username page of the Clerk Dashboard, next to Email address, select the settings icon. A modal will open.
  2. Under Verification methods, enable the Email verification link option. By default, Require the same device and browser is enabled, which means that email links are required to be verified from the same device and browser on which the sign-up or sign-in was initiated. For this guide, leave this setting enabled.
  3. Because this guide focuses on email links, uncheck the box for Email verification code.
  4. Select Continue to save your changes.

Sign-up flow

  1. The useSignUp() hook is used to get the SignUp object.
  2. The SignUp object is used to access the createEmailLinkFlow() method.
  3. The createEmailLinkFlow() method is used to access the startEmailLinkFlow() method.
  4. The startEmailLinkFlow() method is called with the redirectUrl parameter set to /sign-up/verify. It sends an email with a verification link to the user. When the user visits the link, they are redirected to the URL that was provided.
  5. On the /sign-up/verify page, the useClerk() hook is used to get the handleEmailLinkVerification() method.
  6. The handleEmailLinkVerification() method is called to verify the email address. Error handling is included to handle any errors that occur during the verification process.
app/sign-up/page.tsx
'use client'

import * as React from 'react'
import { useSignUp } from '@clerk/nextjs'

export default function SignInPage() {
  const [emailAddress, setEmailAddress] = React.useState('')
  const [verified, setVerified] = React.useState(false)
  const [verifying, setVerifying] = React.useState(false)
  const [error, setError] = React.useState('')
  const { signUp, isLoaded } = useSignUp()

  if (!isLoaded) return null

  const { startEmailLinkFlow } = signUp.createEmailLinkFlow()

  async function submit(e: React.FormEvent) {
    e.preventDefault()
    // Reset states in case user resubmits form mid sign-up
    setVerified(false)
    setError('')

    setVerifying(true)

    if (!isLoaded && !signUp) return null

    // Start the sign-up process using the email provided
    try {
      await signUp.create({
        emailAddress,
      })

      // Dynamically set the host domain for dev and prod
      // You could instead use an environment variable or other source for the host domain
      const protocol = window.location.protocol
      const host = window.location.host

      // Send the user an email with the email link
      const signUpAttempt = await startEmailLinkFlow({
        // URL to navigate to after the user visits the link in their email
        redirectUrl: `${protocol}//${host}/sign-up/verify`,
      })

      // Check the verification result
      const verification = signUpAttempt.verifications.emailAddress

      // Handle if user visited the link and completed sign-up from /sign-up/verify
      if (verification.verifiedFromTheSameClient()) {
        setVerifying(false)
        setVerified(true)
      }
    } catch (err: any) {
      // See https://clerk.com/docs/custom-flows/error-handling
      // for more info on error handling
      console.error(JSON.stringify(err, null, 2))

      if (err.errors?.[0]?.longMessage) {
        console.log('Clerk error:', err.errors[0].longMessage)
        setError(err.errors[0].longMessage)
      } else {
        setError('An error occurred.')
      }
    }
  }

  async function reset(e: React.FormEvent) {
    e.preventDefault()
    setVerifying(false)
  }

  if (error) {
    return (
      <div>
        <p>Error: {error}</p>
        <button onClick={() => setError('')}>Try again</button>
      </div>
    )
  }

  if (verifying) {
    return (
      <div>
        <p>Check your email and visit the link that was sent to you.</p>
        <form onSubmit={reset}>
          <button type="submit">Restart</button>
        </form>
      </div>
    )
  }

  if (verified) {
    return <div>Signed up successfully!</div>
  }

  return (
    <div>
      <h1>Sign up</h1>
      <form onSubmit={submit}>
        <input
          type="email"
          placeholder="Enter email address"
          value={emailAddress}
          onChange={(e) => setEmailAddress(e.target.value)}
        />
        <button type="submit">Continue</button>
      </form>
    </div>
  )
}
app/sign-up/verify/page.tsx
'use client'

import * as React from 'react'
import { useClerk } from '@clerk/nextjs'
import { EmailLinkErrorCodeStatus, isEmailLinkError } from '@clerk/nextjs/errors'
import Link from 'next/link'

export default function VerifyEmailLink() {
  const [verificationStatus, setVerificationStatus] = React.useState('loading')

  const { handleEmailLinkVerification, loaded } = useClerk()

  async function verify() {
    try {
      // Dynamically set the host domain for dev and prod
      // You could instead use an environment variable or other source for the host domain
      const protocol = window.location.protocol
      const host = window.location.host

      await handleEmailLinkVerification({
        // URL to navigate to if sign-up flow needs more requirements, such as MFA
        redirectUrl: `${protocol}//${host}/sign-up`,
      })

      // If not redirected at this point,
      // the flow has completed
      setVerificationStatus('verified')
    } catch (err: any) {
      let status = 'failed'

      if (isEmailLinkError(err)) {
        // If link expired, set status to expired
        if (err.code === EmailLinkErrorCodeStatus.Expired) {
          status = 'expired'
        } else if (err.code === EmailLinkErrorCodeStatus.ClientMismatch) {
          // OPTIONAL: This check is only required if you have
          // the 'Require the same device and browser' setting
          // enabled in the Clerk Dashboard
          status = 'client_mismatch'
        }
      }

      setVerificationStatus(status)
    }
  }

  React.useEffect(() => {
    if (!loaded) return

    verify()
  }, [handleEmailLinkVerification, loaded])

  if (verificationStatus === 'loading') {
    return <div>Loading...</div>
  }

  if (verificationStatus === 'failed') {
    return (
      <div>
        <h1>Verify your email</h1>
        <p>The email link verification failed.</p>
        <Link href="/sign-up">Sign up</Link>
      </div>
    )
  }

  if (verificationStatus === 'expired') {
    return (
      <div>
        <h1>Verify your email</h1>
        <p>The email link has expired.</p>
        <Link href="/sign-up">Sign up</Link>
      </div>
    )
  }

  // OPTIONAL: This check is only required if you have
  // the 'Require the same device and browser' setting
  // enabled in the Clerk Dashboard
  if (verificationStatus === 'client_mismatch') {
    return (
      <div>
        <h1>Verify your email</h1>
        <p>
          You must complete the email link sign-up on the same device and browser that you started
          it on.
        </p>
        <Link href="/sign-up">Sign up</Link>
      </div>
    )
  }

  return (
    <div>
      <h1>Verify your email</h1>
      <p>Successfully signed up. Return to the original tab to continue.</p>
    </div>
  )
}

Sign-in flow

  1. The useSignIn() hook is used to get the SignIn object.
  2. The SignIn object is used to access the createEmailLinkFlow() method.
  3. The createEmailLinkFlow() method is used to access the startEmailLinkFlow() method.
  4. The startEmailLinkFlow() method is called with the redirectUrl parameter set to /sign-in/verify. It sends an email with a verification link to the user. When the user visits the link, they are redirected to the URL that was provided.
  5. On the /sign-in/verify page, the useClerk() hook is used to get the handleEmailLinkVerification() method.
  6. The handleEmailLinkVerification() method is called to verify the email address. Error handling is included to handle any errors that occur during the verification process.
app/sign-in/page.tsx
'use client'

import * as React from 'react'
import { useSignIn } from '@clerk/nextjs'
import { EmailLinkFactor, SignInFirstFactor } from '@clerk/types'

export default function SignInPage() {
  const [emailAddress, setEmailAddress] = React.useState('')
  const [verified, setVerified] = React.useState(false)
  const [verifying, setVerifying] = React.useState(false)
  const [error, setError] = React.useState('')
  const { signIn, isLoaded } = useSignIn()

  if (!isLoaded) return null

  const { startEmailLinkFlow } = signIn.createEmailLinkFlow()

  async function submit(e: React.FormEvent) {
    e.preventDefault()
    // Reset states in case user resubmits form mid sign-in
    setVerified(false)
    setError('')

    if (!isLoaded && !signIn) return null

    // Start the sign-in process using the email provided
    try {
      const { supportedFirstFactors } = await signIn.create({
        identifier: emailAddress,
      })

      setVerifying(true)

      // Filter the returned array to find the 'email_link' entry
      const isEmailLinkFactor = (factor: SignInFirstFactor): factor is EmailLinkFactor => {
        return factor.strategy === 'email_link'
      }
      const emailLinkFactor = supportedFirstFactors?.find(isEmailLinkFactor)

      if (!emailLinkFactor) {
        setError('Email link factor not found')
        return
      }

      const { emailAddressId } = emailLinkFactor

      // Dynamically set the host domain for dev and prod
      // You could instead use an environment variable or other source for the host domain
      const protocol = window.location.protocol
      const host = window.location.host

      // Send the user an email with the email link
      const signInAttempt = await startEmailLinkFlow({
        emailAddressId,
        redirectUrl: `${protocol}//${host}/sign-in/verify`,
      })

      // Check the verification result
      const verification = signInAttempt.firstFactorVerification

      // Handle if verification expired
      if (verification.status === 'expired') {
        setError('The email link has expired.')
      }

      // Handle if user visited the link and completed sign-in from /sign-in/verify
      if (verification.verifiedFromTheSameClient()) {
        setVerifying(false)
        setVerified(true)
      }
    } catch (err: any) {
      // See https://clerk.com/docs/custom-flows/error-handling
      // for more info on error handling
      console.error(JSON.stringify(err, null, 2))
      setError('An error occurred.')
    }
  }

  async function reset(e: React.FormEvent) {
    e.preventDefault()
    setVerifying(false)
  }

  if (error) {
    return (
      <div>
        <p>Error: {error}</p>
        <button onClick={() => setError('')}>Try again</button>
      </div>
    )
  }

  if (verifying) {
    return (
      <div>
        <p>Check your email and visit the link that was sent to you.</p>
        <form onSubmit={reset}>
          <button type="submit">Restart</button>
        </form>
      </div>
    )
  }

  if (verified) {
    return <div>Signed in successfully!</div>
  }

  return (
    <div>
      <h1>Sign in</h1>
      <form onSubmit={submit}>
        <input
          type="email"
          placeholder="Enter email address"
          value={emailAddress}
          onChange={(e) => setEmailAddress(e.target.value)}
        />
        <button type="submit">Continue</button>
      </form>
    </div>
  )
}
app/sign-in/verify/page.tsx
'use client'

import * as React from 'react'
import { useClerk } from '@clerk/nextjs'
import { EmailLinkErrorCodeStatus, isEmailLinkError } from '@clerk/nextjs/errors'
import Link from 'next/link'

export default function VerifyEmailLink() {
  const [verificationStatus, setVerificationStatus] = React.useState('loading')

  const { handleEmailLinkVerification, loaded } = useClerk()

  async function verify() {
    try {
      // Dynamically set the host domain for dev and prod
      // You could instead use an environment variable or other source for the host domain
      const protocol = window.location.protocol
      const host = window.location.host

      await handleEmailLinkVerification({
        // URL to navigate to if sign-in flow needs more requirements, such as MFA
        redirectUrl: `${protocol}//${host}/sign-in`,
      })

      // If not redirected at this point,
      // the flow has completed
      setVerificationStatus('verified')
    } catch (err: any) {
      let status = 'failed'

      if (isEmailLinkError(err)) {
        // If link expired, set status to expired
        if (err.code === EmailLinkErrorCodeStatus.Expired) {
          status = 'expired'
        } else if (err.code === EmailLinkErrorCodeStatus.ClientMismatch) {
          // OPTIONAL: This check is only required if you have
          // the 'Require the same device and browser' setting
          // enabled in the Clerk Dashboard
          status = 'client_mismatch'
        }
      }

      setVerificationStatus(status)
      return
    }
  }

  React.useEffect(() => {
    if (!loaded) return

    verify()
  }, [handleEmailLinkVerification, loaded])

  if (verificationStatus === 'loading') {
    return <div>Loading...</div>
  }

  if (verificationStatus === 'failed') {
    return (
      <div>
        <h1>Verify your email</h1>
        <p>The email link verification failed.</p>
        <Link href="/sign-in">Sign in</Link>
      </div>
    )
  }

  if (verificationStatus === 'expired') {
    return (
      <div>
        <h1>Verify your email</h1>
        <p>The email link has expired.</p>
        <Link href="/sign-in">Sign in</Link>
      </div>
    )
  }

  // OPTIONAL: This check is only required if you have
  // the 'Require the same device and browser' setting
  // enabled in the Clerk Dashboard
  if (verificationStatus === 'client_mismatch') {
    return (
      <div>
        <h1>Verify your email</h1>
        <p>
          You must complete the email link sign-in on the same device and browser as you started it
          on.
        </p>
        <Link href="/sign-in">Sign in</Link>
      </div>
    )
  }

  return (
    <div>
      <h1>Verify your email</h1>
      <p>Successfully signed in. Return to the original tab to continue.</p>
    </div>
  )
}

Add new email flow

When a user adds an email address to their account, you can use email links to verify the email address.

  1. Every user has a User object that represents their account. The User object has a emailAddresses property that contains all the email addresses associated with the user. The useUser() hook is used to get the User object.
  2. The User.createEmailAddress() method is used to add the email address to the user's account. A new EmailAddress object is created and stored in User.emailAddresses.
  3. The newly created EmailAddress object is used to access the createEmailLinkFlow() method.
  4. The createEmailLinkFlow() method is used to access the startEmailLinkFlow() method.
  5. The startEmailLinkFlow() method is called with the redirectUrl parameter set to /account/add-email/verify. It sends an email with a verification link to the user. When the user visits the link, they are redirected to the URL that was provided.
  6. On the /account/add-email/verify page, the useClerk() hook is used to get the handleEmailLinkVerification() method.
  7. The handleEmailLinkVerification() method is called to verify the email address. Error handling is included to handle any errors that occur during the verification process.
app/account/add-email/page.tsx
'use client'

import * as React from 'react'
import { useUser } from '@clerk/nextjs'

export default function Page() {
  const { isLoaded, user } = useUser()
  const [email, setEmail] = React.useState('')
  const [verifying, setVerifying] = React.useState(false)
  const [error, setError] = React.useState('')

  if (!isLoaded) return null

  if (isLoaded && !user?.id) {
    return <p>You must be signed in to access this page</p>
  }

  // Handle addition of the email address
  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault()

    try {
      setVerifying(true)

      // Add an unverified email address to user
      const res = await user.createEmailAddress({ email })
      // Reload user to get updated User object
      await user.reload()

      // Find the email address that was just added
      const emailAddress = user.emailAddresses.find((a) => a.id === res.id)

      if (!emailAddress) {
        setError('Email address not found')
        return
      }

      const { startEmailLinkFlow } = emailAddress.createEmailLinkFlow()

      // Dynamically set the host domain for dev and prod
      // You could instead use an environment variable or other source for the host domain
      const protocol = window.location.protocol
      const host = window.location.host

      // Send the user an email with the verification link
      startEmailLinkFlow({ redirectUrl: `${protocol}//${host}/account/add-email/verify` })
    } catch (err) {
      // See https://clerk.com/docs/custom-flows/error-handling
      // for more info on error handling
      console.error(JSON.stringify(err, null, 2))
      setError('An error occurred.')
    }
  }

  async function reset(e: React.FormEvent) {
    e.preventDefault()
    setVerifying(false)
  }

  if (error) {
    return (
      <div>
        <p>Error: {error}</p>
        <button onClick={() => setError('')}>Try again</button>
      </div>
    )
  }

  if (verifying) {
    return (
      <div>
        <p>Check your email and visit the link that was sent to you.</p>
        <form onSubmit={reset}>
          <button type="submit">Restart</button>
        </form>
      </div>
    )
  }

  // Display the initial form to capture the email address
  return (
    <>
      <h1>Add email</h1>
      <div>
        <form onSubmit={(e) => handleSubmit(e)}>
          <input
            placeholder="Enter email address"
            type="email"
            value={email}
            onChange={(e) => setEmail(e.target.value)}
          />
          <button type="submit">Continue</button>
        </form>
      </div>
    </>
  )
}
app/account/add-email/verify/page.tsx
'use client'

import * as React from 'react'
import { useClerk } from '@clerk/nextjs'
import { EmailLinkErrorCode, isEmailLinkError } from '@clerk/nextjs/errors'
import Link from 'next/link'

export type VerificationStatus =
  | 'expired'
  | 'failed'
  | 'loading'
  | 'verified'
  | 'verified_switch_tab'
  | 'client_mismatch'

export default function VerifyEmailLink() {
  const [verificationStatus, setVerificationStatus] = React.useState('loading')

  const { handleEmailLinkVerification, loaded } = useClerk()

  async function verify() {
    try {
      await handleEmailLinkVerification({})
      setVerificationStatus('verified')
    } catch (err: any) {
      let status: VerificationStatus = 'failed'

      if (isEmailLinkError(err)) {
        // If link expired, set status to expired
        if (err.code === EmailLinkErrorCode.Expired) {
          status = 'expired'
        } else if (err.code === EmailLinkErrorCode.ClientMismatch) {
          // OPTIONAL: This check is only required if you have
          // the 'Require the same device and browser' setting
          // enabled in the Clerk Dashboard
          status = 'client_mismatch'
        }
      }

      setVerificationStatus(status)
      return
    }
  }

  React.useEffect(() => {
    if (!loaded) return

    verify()
  }, [handleEmailLinkVerification, loaded])

  if (verificationStatus === 'loading') {
    return <div>Loading...</div>
  }

  if (verificationStatus === 'failed') {
    return (
      <div>
        <h1>Verify your email</h1>
        <p>The email link verification failed.</p>
        <Link href="/account/add-email">Return to add email</Link>
      </div>
    )
  }

  if (verificationStatus === 'expired') {
    return (
      <div>
        <h1>Verify your email</h1>
        <p>The email link has expired.</p>
        <Link href="/account/add-email">Return to add email</Link>
      </div>
    )
  }

  // OPTIONAL: This check is only required if you have
  // the 'Require the same device and browser' setting
  // enabled in the Clerk Dashboard
  if (verificationStatus === 'client_mismatch') {
    return (
      <div>
        <h1>Verify your email</h1>
        <p>
          You must complete the email link verification on the same device and browser as you
          started it on.
        </p>
        <Link href="/account/add-email">Return to add email</Link>
      </div>
    )
  }

  return (
    <div>
      <h1>Verify your email</h1>
      <p>Successfully added email!</p>
    </div>
  )
}

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