diff --git a/.rubocop.yml b/.rubocop.yml
index 664911bc8..5d150784c 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -391,12 +391,18 @@ Style/IdenticalConditionalBranches:
 Style/MethodDefParentheses:
   Enabled: true
 
+Style/MutableConstant:
+  Enabled: true
+
 Style/Not:
   Enabled: true
 
 Style/PercentLiteralDelimiters:
   Enabled: true
 
+Style/RedundantFreeze:
+  Enabled: true
+
 Style/SafeNavigation:
   Enabled: true
 
diff --git a/app/helpers/embed_videos_helper.rb b/app/helpers/embed_videos_helper.rb
index 08a3179f8..af4f23ac2 100644
--- a/app/helpers/embed_videos_helper.rb
+++ b/app/helpers/embed_videos_helper.rb
@@ -1,6 +1,6 @@
 module EmbedVideosHelper
-  VIMEO_REGEX = /vimeo.*(staffpicks\/|channels\/|videos\/|video\/|\/)([^#\&\?]*).*/
-  YOUTUBE_REGEX = /youtu.*(be\/|v\/|u\/\w\/|embed\/|watch\?v=|\&v=)([^#\&\?]*).*/
+  VIMEO_REGEX = /vimeo.*(staffpicks\/|channels\/|videos\/|video\/|\/)([^#\&\?]*).*/.freeze
+  YOUTUBE_REGEX = /youtu.*(be\/|v\/|u\/\w\/|embed\/|watch\?v=|\&v=)([^#\&\?]*).*/.freeze
 
   def embedded_video_code(resource)
     link = resource.video_url
diff --git a/app/models/activity.rb b/app/models/activity.rb
index a0c862c25..3accc495b 100644
--- a/app/models/activity.rb
+++ b/app/models/activity.rb
@@ -2,7 +2,7 @@ class Activity < ApplicationRecord
   belongs_to :actionable, -> { with_hidden }, polymorphic: true
   belongs_to :user, -> { with_hidden }, inverse_of: :activities
 
-  VALID_ACTIONS = %w[hide block restore valuate email]
+  VALID_ACTIONS = %w[hide block restore valuate email].freeze
 
   validates :action, inclusion: { in: VALID_ACTIONS }
 
diff --git a/app/models/budget/heading.rb b/app/models/budget/heading.rb
index 3e3d8b07d..51616c0a2 100644
--- a/app/models/budget/heading.rb
+++ b/app/models/budget/heading.rb
@@ -1,6 +1,6 @@
 class Budget
   class Heading < ApplicationRecord
-    OSM_DISTRICT_LEVEL_ZOOM = 12.freeze
+    OSM_DISTRICT_LEVEL_ZOOM = 12
 
     include Sluggable
 
diff --git a/app/models/budget/reclassified_vote.rb b/app/models/budget/reclassified_vote.rb
index 1e9053428..ea73d27c1 100644
--- a/app/models/budget/reclassified_vote.rb
+++ b/app/models/budget/reclassified_vote.rb
@@ -1,6 +1,6 @@
 class Budget
   class ReclassifiedVote < ApplicationRecord
-    REASONS = %w[heading_changed unfeasible]
+    REASONS = %w[heading_changed unfeasible].freeze
 
     belongs_to :user
     belongs_to :investment
diff --git a/app/models/concerns/statisticable.rb b/app/models/concerns/statisticable.rb
index 144367559..83ab583f8 100644
--- a/app/models/concerns/statisticable.rb
+++ b/app/models/concerns/statisticable.rb
@@ -1,6 +1,6 @@
 module Statisticable
   extend ActiveSupport::Concern
-  PARTICIPATIONS = %w[gender age geozone]
+  PARTICIPATIONS = %w[gender age geozone].freeze
 
   included do
     attr_reader :resource
diff --git a/app/models/legislation/draft_version.rb b/app/models/legislation/draft_version.rb
index 1e079bb8e..93b65eb8f 100644
--- a/app/models/legislation/draft_version.rb
+++ b/app/models/legislation/draft_version.rb
@@ -1,5 +1,5 @@
 class Legislation::DraftVersion < ApplicationRecord
-  VALID_STATUSES = %w[draft published]
+  VALID_STATUSES = %w[draft published].freeze
 
   acts_as_paranoid column: :hidden_at
   include ActsAsParanoidAliases
diff --git a/app/models/legislation/process.rb b/app/models/legislation/process.rb
index 359c31001..e11bc3b09 100644
--- a/app/models/legislation/process.rb
+++ b/app/models/legislation/process.rb
@@ -23,7 +23,7 @@ class Legislation::Process < ApplicationRecord
                                proposals_phase people_proposals_phase draft_publication
                                result_publication].freeze
 
-  CSS_HEX_COLOR = /\A#?(?:[A-F0-9]{3}){1,2}\z/i
+  CSS_HEX_COLOR = /\A#?(?:[A-F0-9]{3}){1,2}\z/i.freeze
 
   has_many :draft_versions, -> { order(:id) },
     foreign_key: "legislation_process_id",
diff --git a/app/models/poll/partial_result.rb b/app/models/poll/partial_result.rb
index 02b6906b2..134cf377d 100644
--- a/app/models/poll/partial_result.rb
+++ b/app/models/poll/partial_result.rb
@@ -1,5 +1,5 @@
 class Poll::PartialResult < ApplicationRecord
-  VALID_ORIGINS = %w[web booth]
+  VALID_ORIGINS = %w[web booth].freeze
 
   belongs_to :question, -> { with_hidden }, inverse_of: :partial_results
   belongs_to :author, ->   { with_hidden }, class_name: "User", inverse_of: :poll_partial_results
diff --git a/app/models/poll/question/answer/video.rb b/app/models/poll/question/answer/video.rb
index 6cf9e7cc6..5f5407bcc 100644
--- a/app/models/poll/question/answer/video.rb
+++ b/app/models/poll/question/answer/video.rb
@@ -1,8 +1,8 @@
 class Poll::Question::Answer::Video < ApplicationRecord
   belongs_to :answer, class_name: "Poll::Question::Answer"
 
-  VIMEO_REGEX = /vimeo.*(staffpicks\/|channels\/|videos\/|video\/|\/)([^#\&\?]*).*/
-  YOUTUBE_REGEX = /youtu.*(be\/|v\/|u\/\w\/|embed\/|watch\?v=|\&v=)([^#\&\?]*).*/
+  VIMEO_REGEX = /vimeo.*(staffpicks\/|channels\/|videos\/|video\/|\/)([^#\&\?]*).*/.freeze
+  YOUTUBE_REGEX = /youtu.*(be\/|v\/|u\/\w\/|embed\/|watch\?v=|\&v=)([^#\&\?]*).*/.freeze
 
   validates :title, presence: true
   validate :valid_url?
diff --git a/app/models/progress_bar.rb b/app/models/progress_bar.rb
index f60e4f2b3..3da9c072b 100644
--- a/app/models/progress_bar.rb
+++ b/app/models/progress_bar.rb
@@ -1,6 +1,6 @@
 class ProgressBar < ApplicationRecord
   self.inheritance_column = nil
-  RANGE = 0..100
+  RANGE = (0..100).freeze
 
   enum kind: %i[primary secondary]
 
diff --git a/app/models/proposal.rb b/app/models/proposal.rb
index c02e09bd1..ce223cdaa 100644
--- a/app/models/proposal.rb
+++ b/app/models/proposal.rb
@@ -26,7 +26,7 @@ class Proposal < ApplicationRecord
   acts_as_paranoid column: :hidden_at
   include ActsAsParanoidAliases
 
-  RETIRE_OPTIONS = %w[duplicated started unfeasible done other]
+  RETIRE_OPTIONS = %w[duplicated started unfeasible done other].freeze
 
   translates :title, touch: true
   translates :description, touch: true
diff --git a/app/models/report.rb b/app/models/report.rb
index 857cb462f..e8d26a829 100644
--- a/app/models/report.rb
+++ b/app/models/report.rb
@@ -1,5 +1,5 @@
 class Report < ApplicationRecord
-  KINDS = %i[results stats advanced_stats]
+  KINDS = %i[results stats advanced_stats].freeze
 
   belongs_to :process, polymorphic: true
 end
diff --git a/app/models/signature_sheet.rb b/app/models/signature_sheet.rb
index cf67804b2..fae7b7a3c 100644
--- a/app/models/signature_sheet.rb
+++ b/app/models/signature_sheet.rb
@@ -2,7 +2,7 @@ class SignatureSheet < ApplicationRecord
   belongs_to :signable, polymorphic: true
   belongs_to :author, class_name: "User"
 
-  VALID_SIGNABLES = %w[Proposal Budget::Investment]
+  VALID_SIGNABLES = %w[Proposal Budget::Investment].freeze
 
   has_many :signatures
 
diff --git a/app/models/site_customization/content_block.rb b/app/models/site_customization/content_block.rb
index a96bc8b47..a41580e36 100644
--- a/app/models/site_customization/content_block.rb
+++ b/app/models/site_customization/content_block.rb
@@ -1,5 +1,5 @@
 class SiteCustomization::ContentBlock < ApplicationRecord
-  VALID_BLOCKS = %w[top_links footer subnavigation_left subnavigation_right]
+  VALID_BLOCKS = %w[top_links footer subnavigation_left subnavigation_right].freeze
 
   validates :locale, presence: true, inclusion: { in: I18n.available_locales.map(&:to_s) }
   validates :name, presence: true, uniqueness: { scope: :locale }, inclusion: { in: VALID_BLOCKS }
diff --git a/app/models/site_customization/image.rb b/app/models/site_customization/image.rb
index 0ebf1f929..77f0e16ab 100644
--- a/app/models/site_customization/image.rb
+++ b/app/models/site_customization/image.rb
@@ -7,7 +7,7 @@ class SiteCustomization::Image < ApplicationRecord
     "budget_execution_no_image" => [800, 600],
     "map" => [420, 500],
     "logo_email" => [400, 80]
-  }
+  }.freeze
 
   has_attached_file :image
 
diff --git a/app/models/site_customization/page.rb b/app/models/site_customization/page.rb
index be59d0dcd..03c4bcccc 100644
--- a/app/models/site_customization/page.rb
+++ b/app/models/site_customization/page.rb
@@ -1,5 +1,5 @@
 class SiteCustomization::Page < ApplicationRecord
-  VALID_STATUSES = %w[draft published]
+  VALID_STATUSES = %w[draft published].freeze
   has_many :cards,
     class_name:  "Widget::Card",
     foreign_key: "site_customization_page_id",
diff --git a/app/models/widget/feed.rb b/app/models/widget/feed.rb
index 3e52e81d6..d90cdee2d 100644
--- a/app/models/widget/feed.rb
+++ b/app/models/widget/feed.rb
@@ -1,7 +1,7 @@
 class Widget::Feed < ApplicationRecord
   self.table_name = "widget_feeds"
 
-  KINDS = %w[proposals debates processes]
+  KINDS = %w[proposals debates processes].freeze
 
   def active?
     setting.value.present?
diff --git a/lib/graph_ql/api_types_creator.rb b/lib/graph_ql/api_types_creator.rb
index 0fca95f61..823e430a8 100644
--- a/lib/graph_ql/api_types_creator.rb
+++ b/lib/graph_ql/api_types_creator.rb
@@ -8,7 +8,7 @@ module GraphQL
       float: GraphQL::FLOAT_TYPE,
       double: GraphQL::FLOAT_TYPE,
       string: GraphQL::STRING_TYPE
-    }
+    }.freeze
 
     def self.create(api_types_definitions)
       created_types = {}
diff --git a/lib/remote_translations/microsoft/client.rb b/lib/remote_translations/microsoft/client.rb
index 5c4f33d34..d7e1bc5d9 100644
--- a/lib/remote_translations/microsoft/client.rb
+++ b/lib/remote_translations/microsoft/client.rb
@@ -3,7 +3,7 @@ include RemoteTranslations::Microsoft::SentencesParser
 
 class RemoteTranslations::Microsoft::Client
   CHARACTERS_LIMIT_PER_REQUEST = 5000
-  PREVENTING_TRANSLATION_KEY = "notranslate"
+  PREVENTING_TRANSLATION_KEY = "notranslate".freeze
 
   def initialize
     api_key = Rails.application.secrets.microsoft_api_key
diff --git a/lib/tag_sanitizer.rb b/lib/tag_sanitizer.rb
index 4a15ab1b8..eedf1f5af 100644
--- a/lib/tag_sanitizer.rb
+++ b/lib/tag_sanitizer.rb
@@ -1,5 +1,5 @@
 class TagSanitizer
-  DISALLOWED_STRINGS = %w[? < > = /]
+  DISALLOWED_STRINGS = %w[? < > = /].freeze
 
   def sanitize_tag(tag)
     tag = tag.dup
diff --git a/lib/user_segments.rb b/lib/user_segments.rb
index d6bd427fb..bf30f4416 100644
--- a/lib/user_segments.rb
+++ b/lib/user_segments.rb
@@ -7,7 +7,7 @@ class UserSegments
                 feasible_and_undecided_investment_authors
                 selected_investment_authors
                 winner_investment_authors
-                not_supported_on_current_budget]
+                not_supported_on_current_budget].freeze
 
   def self.all_users
     User.active