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Build a custom flow for adding a phone number to a user's account

Warning

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

Users are able to add multiple phone numbers to their account.

Every user has a User object that represents their account. The User object has a phoneNumbers property that contains all the phone numbers associated with the user.

The following example demonstrates how to build a custom user interface that allows users to add a phone number to their account. The example:

  1. Uses the useUser() hook to get the User object.
  2. Uses the User.createPhoneNumber() method to add the phone number to the user's account. A new PhoneNumber object is created and stored in User.phoneNumbers.
  3. Uses the prepareVerification() method on the newly created PhoneNumber object to send a verification code to the user.
  4. Uses the attemptVerification() method on the same PhoneNumber object with the verification code provided by the user to verify the phone number.
app/account/add-phone/page.tsx
'use client'

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

export default function Page() {
  const { isLoaded, user } = useUser()
  const [phone, setPhone] = React.useState('')
  const [code, setCode] = React.useState('')
  const [isVerifying, setIsVerifying] = React.useState(false)
  const [successful, setSuccessful] = React.useState(false)
  const [phoneObj, setPhoneObj] = React.useState<PhoneNumberResource | undefined>()

  if (!isLoaded) return null

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

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

    try {
      // Add unverified phone number to user
      const res = await user.createPhoneNumber({ phoneNumber: phone })
      // Reload user to get updated User object
      await user.reload()

      // Create a reference to the new phone number to use related methods
      const phoneNumber = user.phoneNumbers.find((a) => a.id === res.id)
      setPhoneObj(phoneNumber)

      // Send the user an SMS with the verification code
      phoneNumber?.prepareVerification()

      // Set to true to display second form
      // and capture the OTP code
      setIsVerifying(true)
    } catch (err) {
      // See https://clerk.com/docs/custom-flows/error-handling
      // for more info on error handling
      console.error(JSON.stringify(err, null, 2))
    }
  }

  // Handle the submission of the verification form
  const verifyCode = async (e: React.FormEvent) => {
    e.preventDefault()
    try {
      // Verify that the provided code matches the code sent to the user
      const phoneVerifyAttempt = await phoneObj?.attemptVerification({ code })

      if (phoneVerifyAttempt?.verification.status === 'verified') {
        setSuccessful(true)
      } else {
        // If the status is not complete, check why. User may need to
        // complete further steps.
        console.error(JSON.stringify(phoneVerifyAttempt, null, 2))
      }
    } catch (err) {
      console.error(JSON.stringify(err, null, 2))
    }
  }

  // Display a success message if the phone number was added successfully
  if (successful) {
    return (
      <>
        <h1>Phone added</h1>
      </>
    )
  }

  // Display the verification form to capture the OTP code
  if (isVerifying) {
    return (
      <>
        <h1>Verify phone</h1>
        <div>
          <form onSubmit={(e) => verifyCode(e)}>
            <div>
              <label htmlFor="code">Enter code</label>
              <input
                onChange={(e) => setCode(e.target.value)}
                id="code"
                name="code"
                type="text"
                value={code}
              />
            </div>
            <div>
              <button type="submit">Verify</button>
            </div>
          </form>
        </div>
      </>
    )
  }

  // Display the initial form to capture the phone number
  return (
    <>
      <h1>Add phone</h1>
      <div>
        <form onSubmit={(e) => handleSubmit(e)}>
          <div>
            <label htmlFor="phone">Enter phone number</label>
            <input
              onChange={(e) => setPhone(e.target.value)}
              id="phone"
              name="phone"
              type="phone"
              value={phone}
            />
          </div>
          <div>
            <button type="submit">Continue</button>
          </div>
        </form>
      </div>
    </>
  )
}
AddPhoneView.swift
import SwiftUI
import ClerkSDK

struct AddPhoneView: View {
  @State private var phone = ""
  @State private var code = ""
  @State private var isVerifying = false
  // Create a reference to the phone number that we'll be creating
  @State private var newPhoneNumber: PhoneNumber?

  var body: some View {
    if newPhoneNumber?.verification?.status == .verified {
      Text("Phone added!")
    }

    if isVerifying {
      TextField("Enter code", text: $code)
      Button("Verify") {
        Task { await verifyCode(code) }
      }
    } else {
      TextField("Enter phone number", text: $phone)
      Button("Continue") {
        Task { await createPhone(phone) }
      }
    }
  }
}

extension AddPhoneView {

  func createPhone(_ phone: String) async {
    do {
      guard let user = Clerk.shared.user else { return }

      // Add an unverified phone number to user
      self.newPhoneNumber = try await user.createPhoneNumber(phone)

      guard let newphoneNumber = self.newPhoneNumber else { return }

      // Send the user an sms message with the verification code
      try await newphoneNumber.prepareVerification()

      // Set to true to display second form
      // and capture the OTP code
      isVerifying = true
    } catch {
      // See https://clerk.com/docs/custom-flows/error-handling
      // for more info on error handling
      dump(error)
    }
  }

  func verifyCode(_ code: String) async {
    do {
      guard let newPhoneNumber else { return }

      // Verify that the code entered matches the code sent to the user
      self.newPhoneNumber = try await newPhoneNumber.attemptVerification(code: code)

      // If the status is not complete, check why. User may need to
      // complete further steps.
      dump(self.newPhoneNumber?.verification?.status)
    } catch {
      // See https://clerk.com/docs/custom-flows/error-handling
      // for more info on error handling
      dump(error)
    }
  }
}

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