How to allow users to sign in using mobile number with Devise and Rails?

Most people in the world who use smartphones don’t own/use email. However they know how to operate the mobile and apps.

What if you need to build an app for such users who want to access your app and it requires some kind of authentication mechanism?

If you are building a web application using rails, the natural choice for authentication would be Devise. Conventionally Device’s promotes email to authenticate users. Replacing email with mobile as authentication key needs some tweaks in configurations.


Ensure you have configured root in your application inside config/routes.rb. You can skip this section and jump to Install Devise step

If you just created a new rails app, let us create a simple HomeController with index action for demo purpose. Run following from command line

rails g controller Home index

Then change config/routes.rb and configure root

root 'home#index'

Install Devise

You can skip this step if you have already set up the Device.

  1. Modify Gemfile Add gem 'devise' to your Gemfile and run bundle install from the command line

  2. Run Devise Generator Next, run rails generate devise:install from the command line

Follow instructions appear in the console to complete configuration.

Create Model

Create a model for authentication passing mobile as additional field

rails generate devise User mobile

Modify Generated Migration

Devise is going to use mobile to find matching user in the app so we should add index to mobile to make searching faster. This command creates User model, creates a migration for it and changes routes.rb to add Devise specific routes.

Open the generated migration and make following changes

  1. Mark mobile field as not null
t.string :mobile, null: false

Add following line below the the index for email

add_index :users, :mobile,               unique: true

Run Migration

Run rails db:migrate from the command line to create users table.

Enable Authentication

Assuming you want to protect all views/controllers, add following to enable authentication for all controllers in ApplicationController

before_action :authenticate_user!

Now start rails server and hit http://localhost:3000 to verify the setup. You should get a login page.

Override Devise’s Default Views

Devise provides default views for Sign In, Sign Up, Reset Password etc. All those views are configured to use email which we need to replace with mobile.

  1. Copy views from Devise to your app
    Run rails generate devise:views from command line

  2. Replace email with mobile in Sign In and Sign Up devise views
    Open app/views/devise/sessions/new.html.erb and app/views/devise/registrations/new.html.erb to replace email with mobile
    Also, replace email_filed with telephone_field. The updated configuration will look like in both views

<div class="field">
 <%= f.label :mobile %><br />
 <%= f.telephone_field :mobile, autofocus: true, autocomplete: "mobile" %>

Whitelist mobile param via Strong parameters

Devise controllers santize parameters to ensure only require parameters are sent and rest are ignored. We added mobile field which is not in the whitelist provided by Deviase. We need to add it to ensure it is allowed to use by Devise. Here is how it looks like:

class ApplicationController < ActionController::Base
  before_action :configure_permitted_parameters, if: :devise_controller?
  before_action :authenticate_user!


  def configure_permitted_parameters
    devise_parameter_sanitizer.permit(:sign_up, keys: [:mobile])
    devise_parameter_sanitizer.permit(:sign_in, keys: [:mobile])

Check Whitelisting Custom Fields for more details.

Override Devise’s Default Model Configuration

Add following to your User model to avoid email as authentication key

validates :email, uniqueness: true
validates :mobile, uniqueness: true

# Search user by mobile(not email)
def self.find_first_by_auth_conditions(warden_conditions)
  conditions = warden_conditions.dup
  where(mobile: conditions[:mobile]).first

# Stop using email as authentication key
def email_required?

def email_changed?

def will_save_change_to_email?

Refer How To: Allow users to sign in using their username or email address For more details

Change Initializer to support mobile as authentication key

Open config/initializers/devise.rb and ensure following configuration:

config.authentication_keys = [:mobile]
config.case_insensitive_keys = [:mobile]
config.strip_whitespace_keys = [:mobile]

And….That’s it. Now restart the rails server and we are done!

You can find the working application here on Github and take a look at commits.

P.S. You can use any custom field instead of mobile.