diff --git a/backend/Gemfile b/backend/Gemfile
index f2a3faf61..c2ad1a783 100644
--- a/backend/Gemfile
+++ b/backend/Gemfile
@@ -65,6 +65,8 @@ gem 'kaminari-mongoid'
 gem 'kaminari-actionview'
 gem 'rack-cors', require: 'rack/cors'
 
+gem 'httparty'
+
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'byebug'
diff --git a/backend/Gemfile.lock b/backend/Gemfile.lock
index 51d862f0a..1420b1013 100644
--- a/backend/Gemfile.lock
+++ b/backend/Gemfile.lock
@@ -114,6 +114,8 @@ GEM
       activerecord (>= 4.2.0, < 4.3)
     hashdiff (0.3.0)
     hashie (3.4.3)
+    httparty (0.16.0)
+      multi_xml (>= 0.5.2)
     httpclient (2.7.1)
     i18n (0.7.0)
     i18n_data (0.7.0)
@@ -329,6 +331,7 @@ DEPENDENCIES
   foreman
   geocoder
   globalize (~> 5.0.0)
+  httparty
   kaminari-actionview
   kaminari-mongoid
   letter_opener (~> 1.4)
diff --git a/backend/app/controllers/api/v1/checkins_controller.rb b/backend/app/controllers/api/v1/checkins_controller.rb
index 3b07acf7a..a50dff21b 100644
--- a/backend/app/controllers/api/v1/checkins_controller.rb
+++ b/backend/app/controllers/api/v1/checkins_controller.rb
@@ -17,6 +17,11 @@ def show
   def create
     date = params.require(:checkin).require(:date)
     checkin = Checkin::Creator.new(current_user.id, Date.parse(date)).create!
+
+    SendDataToSendy.perform_async(name: current_user.screen_name,
+                                  email: current_user.email,
+                                  last_checkin_at: checkin.date)
+
     render json: checkin
   end
 
diff --git a/backend/app/jobs/send_data_to_sendy.rb b/backend/app/jobs/send_data_to_sendy.rb
new file mode 100644
index 000000000..77d9d9efc
--- /dev/null
+++ b/backend/app/jobs/send_data_to_sendy.rb
@@ -0,0 +1,18 @@
+class SendDataToSendy
+  include Sidekiq::Worker
+
+  def perform(options)
+    email = options['email']
+    return unless email.present?
+
+    user = User.find_by(email: email)
+    return unless user
+
+    last_checkin_at = options['last_checkin_at'] || ''
+
+    SendyService.new(name: options['name'],
+                     email: email,
+                     signup_at: user.created_at.to_date,
+                     last_checkin_at: last_checkin_at).send_data
+  end
+end
diff --git a/backend/app/models/registration.rb b/backend/app/models/registration.rb
index 8becdb54a..bf4632228 100644
--- a/backend/app/models/registration.rb
+++ b/backend/app/models/registration.rb
@@ -23,6 +23,8 @@ def save!
     begin
       @user = User.create!(@user_params)
       @user.profile.update_attributes!(screen_name: screen_name) if screen_name.present?
+
+      SendDataToSendy.perform_async(name: screen_name, email: @user.email)
     rescue ActiveRecord::RecordInvalid => e
       self.errors = e.record.errors
       raise ActiveRecord::RecordInvalid, self
diff --git a/backend/app/services/sendy_service.rb b/backend/app/services/sendy_service.rb
new file mode 100644
index 000000000..f48679428
--- /dev/null
+++ b/backend/app/services/sendy_service.rb
@@ -0,0 +1,55 @@
+require 'httparty'
+
+class SendyService
+  attr_accessor :api_key, :email, :name, :signup_at, :last_checkin_at
+
+  # Default API endpoints
+  BASE_URL = ENV['SENDI_INSTALLATION']
+  LIST_ID = ENV['SENDI_LIST_ID']
+
+  def initialize(options)
+    @api_key = ENV['SENDI_API_KEY']
+    @email = options[:email]
+    @name = options[:name]
+    @signup_at = options[:signup_at]
+    @last_checkin_at = options[:last_checkin_at]
+  end
+
+  def send_data
+    post('subscribe', name: name,
+                      email: email,
+                      signup_at: signup_at,
+                      last_checkin_at: last_checkin_at,
+                      boolean: true, api_key: api_key, list: LIST_ID)
+  end
+
+  def get(path)
+    execute :get, path, nil
+  end
+
+  def post(path, data = nil)
+    execute :post, path, data
+  end
+
+  def execute(method, path, data = nil)
+    response = request(method, path, data)
+
+    case response.code
+    when 200..299
+      response
+    when 401
+      raise AuthenticationFailed, response["message"]
+    when 404
+      raise NotFoundError, response
+    else
+      raise RequestError, response
+    end
+  end
+
+  def request(method, path, data = nil)
+    headers = {}
+    headers['content-type'] = "application/x-www-form-urlencoded"
+
+    HTTParty.send(method, BASE_URL + path, headers: headers, body: data)
+  end
+end