diff --git a/Gemfile b/Gemfile
index ce4173db7e..e49d01b418 100644
--- a/Gemfile
+++ b/Gemfile
@@ -62,6 +62,7 @@ gem 'graphiql-rails', git: 'https://github.com/meedan/graphiql-rails.git', ref:
 gem 'graphql-formatter'
 gem 'nokogiri', '1.14.3'
 gem 'puma'
+gem 'rack-attack'
 gem 'rack-cors', '1.0.6', require: 'rack/cors'
 gem 'sidekiq', '5.2.10'
 gem 'sidekiq-cloudwatchmetrics'
diff --git a/Gemfile.lock b/Gemfile.lock
index 876aec8c6a..1f1facb61d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -637,6 +637,8 @@ GEM
     raabro (1.4.0)
     racc (1.7.1)
     rack (2.2.6.4)
+    rack-attack (6.7.0)
+      rack (>= 1.0, < 4)
     rack-cors (1.0.6)
       rack (>= 1.6.0)
     rack-protection (2.2.0)
@@ -983,6 +985,7 @@ DEPENDENCIES
   puma
   pusher
   rack (= 2.2.6.4)
+  rack-attack
   rack-cors (= 1.0.6)
   rack-protection (= 2.2.0)
   railroady
diff --git a/app/models/bot/smooch.rb b/app/models/bot/smooch.rb
index c0c0e6ebc2..7f0ac223ae 100644
--- a/app/models/bot/smooch.rb
+++ b/app/models/bot/smooch.rb
@@ -302,7 +302,7 @@ def self.run(body)
       when 'message:delivery:failure'
         self.resend_message(json)
         true
-      when 'conversation:start'
+      when 'conversation:start', 'conversation:referral'
         message = {
           '_id': json['conversation']['_id'],
           authorId: json['appUser']['_id'],
diff --git a/app/models/user.rb b/app/models/user.rb
index 6384fac4aa..64bcc7b4b3 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -30,7 +30,7 @@ class ToSOrPrivacyPolicyReadError < StandardError; end
 
   devise :registerable,
          :recoverable, :rememberable, :trackable, :validatable, :confirmable,
-         :omniauthable, omniauth_providers: [:twitter, :facebook, :slack, :google_oauth2]
+         :omniauthable, :lockable, omniauth_providers: [:twitter, :facebook, :slack, :google_oauth2]
 
   before_create :skip_confirmation_for_non_email_provider
   after_create :create_source_and_account, :set_source_image, :send_welcome_email
diff --git a/config/application.rb b/config/application.rb
index 8862b01770..b3a6dac1e3 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -99,5 +99,8 @@ class Application < Rails::Application
     })
 
     config.active_record.yaml_column_permitted_classes = [Time, Symbol]
+
+    # Rack Attack Configuration
+    config.middleware.use Rack::Attack
   end
 end
diff --git a/config/config.yml.example b/config/config.yml.example
index 873865aebc..e34a778e2c 100644
--- a/config/config.yml.example
+++ b/config/config.yml.example
@@ -268,6 +268,10 @@ development: &default
   nlu_global_rate_limit: 100
   nlu_user_rate_limit: 30
 
+  devise_maximum_attempts: 5
+  devise_unlock_accounts_after: 1
+  login_rate_limit: 10
+  api_rate_limit: 100
 test:
   <<: *default
   checkdesk_base_url_private: http://api:3000
diff --git a/config/environments/test.rb b/config/environments/test.rb
index 592c08505d..6e70ec23e3 100644
--- a/config/environments/test.rb
+++ b/config/environments/test.rb
@@ -23,7 +23,8 @@
 
   # Show full error reports and disable caching.
   config.consider_all_requests_local       = true
-  config.action_controller.perform_caching = false
+  config.action_controller.perform_caching = true
+  config.cache_store = :memory_store
 
   # Raise exceptions instead of rendering exception templates.
   config.action_dispatch.show_exceptions = false
diff --git a/config/initializers/devise.rb b/config/initializers/devise.rb
index 0c43abae93..72f1482708 100644
--- a/config/initializers/devise.rb
+++ b/config/initializers/devise.rb
@@ -49,6 +49,13 @@ def http_auth_body
   end
   config.mailer = 'DeviseMailer'
   config.invite_for = 1.month
+
+  # Account lockout
+  config.lock_strategy = :failed_attempts
+  config.unlock_strategy = :both
+  config.unlock_keys = [ :time ]
+  config.maximum_attempts = CheckConfig.get('devise_maximum_attempts', 5)
+  config.unlock_in = CheckConfig.get('devise_unlock_accounts_after', 1).hour
 end
 
 AuthTrail.geocode = false
diff --git a/config/initializers/rack_attack.rb b/config/initializers/rack_attack.rb
new file mode 100644
index 0000000000..f1971262b4
--- /dev/null
+++ b/config/initializers/rack_attack.rb
@@ -0,0 +1,21 @@
+class Rack::Attack
+  # Throttle login attempts by IP address
+  throttle('logins/ip', limit: proc { CheckConfig.get('login_rate_limit', 10, :integer) }, period: 60.seconds) do |req|
+    if req.path == '/api/users/sign_in' && req.post?
+      req.ip
+    end
+  end
+
+  # Throttle login attempts by email address
+  throttle('logins/email', limit: proc { CheckConfig.get('login_rate_limit', 10, :integer) }, period: 60.seconds) do |req|
+    if req.path == '/api/users/sign_in' && req.post?
+      # Return the email if present, nil otherwise
+      req.params['user']['email'].presence if req.params['user']
+    end
+  end
+
+  # Throttle all graphql requests by IP address
+  throttle('api/graphql', limit:  proc { CheckConfig.get('api_rate_limit', 100, :integer) }, period: 60.seconds) do |req|
+    req.ip if req.path == '/api/graphql'
+  end
+end
diff --git a/db/migrate/20240115101312_add_lockable_to_devise.rb b/db/migrate/20240115101312_add_lockable_to_devise.rb
new file mode 100644
index 0000000000..2e49cd2a9c
--- /dev/null
+++ b/db/migrate/20240115101312_add_lockable_to_devise.rb
@@ -0,0 +1,7 @@
+class AddLockableToDevise < ActiveRecord::Migration[6.1]
+  def change
+    add_column :users, :failed_attempts, :integer, default: 0, null: false
+    add_column :users, :unlock_token, :string
+    add_column :users, :locked_at, :datetime
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index b3db55b598..9839702263 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2024_01_14_024701) do
+ActiveRecord::Schema.define(version: 2024_01_15_101312) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -669,7 +669,6 @@
     t.datetime "updated_at", null: false
     t.string "state"
     t.index ["external_id", "state"], name: "index_tipline_messages_on_external_id_and_state", unique: true
-    t.index ["external_id"], name: "index_tipline_messages_on_external_id"
     t.index ["team_id"], name: "index_tipline_messages_on_team_id"
     t.index ["uid"], name: "index_tipline_messages_on_uid"
   end
@@ -799,6 +798,9 @@
     t.integer "consumed_timestep"
     t.boolean "otp_required_for_login"
     t.string "otp_backup_codes", array: true
+    t.integer "failed_attempts", default: 0, null: false
+    t.string "unlock_token"
+    t.datetime "locked_at"
     t.index ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true
     t.index ["email"], name: "index_users_on_email", unique: true, where: "((email IS NOT NULL) AND ((email)::text <> ''::text))"
     t.index ["invitation_token"], name: "index_users_on_invitation_token", unique: true
@@ -810,7 +812,8 @@
   end
 
   create_table "versions", id: :serial, force: :cascade do |t|
-    t.string "item_type", null: false
+    t.string "item_type"
+    t.string "{:null=>false}"
     t.string "item_id", null: false
     t.string "event", null: false
     t.string "whodunnit"
diff --git a/test/controllers/sessions_controller_test.rb b/test/controllers/sessions_controller_test.rb
index 76a9ccf4a6..ce63e1c7c0 100644
--- a/test/controllers/sessions_controller_test.rb
+++ b/test/controllers/sessions_controller_test.rb
@@ -71,5 +71,35 @@ def setup
     assert_not_nil @controller.current_api_user
   end
 
+  test "should lock user after excessive login requests" do
+    u = create_user login: 'test', password: '12345678', password_confirmation: '12345678', email: 'test@test.com'
+    u.confirm
+    Devise.maximum_attempts = 2
+
+    2.times do
+      post :create, params: { api_user: { email: 'test@test.com', password: '12345679' } }
+    end
+
+    u.reload
+    assert u.access_locked?
+    assert_not_nil u.locked_at
+  end
+
+  test "should unlock locked user accounts after specified time" do
+    u = create_user login: 'test', password: '12345678', password_confirmation: '12345678', email: 'test@test.com'
+    u.confirm
+    maximum_attempts = Devise.maximum_attempts
+
+    maximum_attempts.times do
+      post :create, params: { api_user: { email: 'test@test.com', password: '12345679' } }
+    end
+
+    travel_to  CheckConfig.get('devise_unlock_accounts_after', 5, :integer).hours.from_now + 1.hour do
+      u.reload
+      assert !u.access_locked?
+      assert_nil u.locked_at
+    end
+  end
+
 
 end
diff --git a/test/lib/check_rack_attack_test.rb b/test/lib/check_rack_attack_test.rb
new file mode 100644
index 0000000000..ce32666574
--- /dev/null
+++ b/test/lib/check_rack_attack_test.rb
@@ -0,0 +1,32 @@
+require 'test_helper'
+
+class ThrottlingTest < ActionDispatch::IntegrationTest
+  setup do
+    Rails.cache.clear
+  end
+
+  test "should throttle excessive requests to /api/graphql" do
+    stub_configs({ 'api_rate_limit' => 2 }) do
+      2.times do
+        post api_graphql_path
+        assert_response :unauthorized
+      end
+
+      post api_graphql_path
+      assert_response :too_many_requests
+    end
+  end
+
+  test "should throttle excessive requests to /api/users/sign_in" do
+    stub_configs({ 'login_rate_limit' => 2 }) do
+      user_params = { api_user: { email: 'user@example.com', password: 'password' } }
+
+      2.times do
+        post api_user_session_path, params: user_params, as: :json
+      end
+
+      post api_user_session_path, params: user_params, as: :json
+      assert_response :too_many_requests
+    end
+  end
+end