diff --git a/app/controllers/access_controller.rb b/app/controllers/access_controller.rb
index a83fd128..2441aa62 100644
--- a/app/controllers/access_controller.rb
+++ b/app/controllers/access_controller.rb
@@ -6,7 +6,6 @@ class AccessController < ApplicationController
                                  :deny_access, :deny_access_post, :request_access]
   after_action :verify_authorized
 
-
   # GET maps/:id/request_access
   def request_access
     @map = nil
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 4285682e..4bb5be10 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -22,7 +22,7 @@ class ApplicationController < ActionController::Base
   helper_method :admin?
 
   def handle_unauthorized
-    if authenticated? and params[:controller] == 'maps' and params[:action] == 'show'
+    if authenticated? && (params[:controller] == 'maps') && (params[:action] == 'show')
       redirect_to request_access_map_path(params[:id])
     elsif authenticated?
       redirect_to root_path, notice: "You don't have permission to see that page."
@@ -41,13 +41,13 @@ class ApplicationController < ActionController::Base
   def require_no_user
     return true unless authenticated?
     redirect_to edit_user_path(user), notice: 'You must be logged out.'
-    return false
+    false
   end
 
   def require_user
     return true if authenticated?
     redirect_to sign_in_path, notice: 'You must be logged in.'
-    return false
+    false
   end
 
   def require_admin
diff --git a/app/controllers/topics_controller.rb b/app/controllers/topics_controller.rb
index ea56059b..b54cc4f5 100644
--- a/app/controllers/topics_controller.rb
+++ b/app/controllers/topics_controller.rb
@@ -14,14 +14,14 @@ class TopicsController < ApplicationController
       @topics = policy_scope(Topic).where('LOWER("name") like ?', term.downcase + '%').order('"name"')
       @mapTopics = @topics.select { |t| t&.metacode&.name == 'Metamap' }
       # prioritize topics which point to maps, over maps
-      @exclude = @mapTopics.length > 0 ? @mapTopics.map(&:name) : ['']
+      @exclude = @mapTopics.length.positive? ? @mapTopics.map(&:name) : ['']
       @maps = policy_scope(Map).where('LOWER("name") like ? AND name NOT IN (?)', term.downcase + '%', @exclude).order('"name"')
     else
       @topics = []
       @maps = []
     end
-    @all= @topics.to_a.concat(@maps.to_a).sort { |a, b| a.name <=> b.name }
-    
+    @all = @topics.to_a.concat(@maps.to_a).sort_by(&:name)
+
     render json: autocomplete_array_json(@all).to_json
   end
 
diff --git a/app/controllers/users/registrations_controller.rb b/app/controllers/users/registrations_controller.rb
index 7c211f26..44bcb2de 100644
--- a/app/controllers/users/registrations_controller.rb
+++ b/app/controllers/users/registrations_controller.rb
@@ -21,13 +21,10 @@ class Users::RegistrationsController < Devise::RegistrationsController
     end
   end
 
-
   private
 
   def store_location
-    if params[:redirect_to]
-      store_location_for(User, params[:redirect_to])    
-    end
+    store_location_for(User, params[:redirect_to]) if params[:redirect_to]
   end
 
   def configure_sign_up_params
diff --git a/app/helpers/topics_helper.rb b/app/helpers/topics_helper.rb
index 58f53a6e..fa26095d 100644
--- a/app/helpers/topics_helper.rb
+++ b/app/helpers/topics_helper.rb
@@ -20,7 +20,7 @@ module TopicsHelper
         type: is_map ? metamapMetacode.name : t.metacode.name,
         typeImageURL: is_map ? metamapMetacode.icon : t.metacode.icon,
         mapCount: is_map ? 0 : t.maps.count,
-        synapseCount: is_map ? 0 : t.synapses.count,
+        synapseCount: is_map ? 0 : t.synapses.count
       }
     end
   end
diff --git a/app/models/access_request.rb b/app/models/access_request.rb
index e5416fff..fe68ce8f 100644
--- a/app/models/access_request.rb
+++ b/app/models/access_request.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class AccessRequest < ApplicationRecord
   belongs_to :user
   belongs_to :map
@@ -5,7 +6,7 @@ class AccessRequest < ApplicationRecord
   def approve
     self.approved = true
     self.answered = true
-    self.save
+    save
 
     Mailboxer::Notification.where(notified_object: self).find_each do |notification|
       Mailboxer::Receipt.where(notification: notification).update_all(is_read: true)
@@ -18,7 +19,7 @@ class AccessRequest < ApplicationRecord
   def deny
     self.approved = false
     self.answered = true
-    self.save
+    save
 
     Mailboxer::Notification.where(notified_object: self).find_each do |notification|
       Mailboxer::Receipt.where(notification: notification).update_all(is_read: true)
@@ -26,10 +27,10 @@ class AccessRequest < ApplicationRecord
   end
 
   def requested_text
-    self.map.name + ' - request to edit' 
+    map.name + ' - request to edit'
   end
 
   def approved_text
-    self.map.name + ' - access approved' 
+    map.name + ' - access approved'
   end
 end
diff --git a/app/models/map.rb b/app/models/map.rb
index 5744b856..899992c6 100644
--- a/app/models/map.rb
+++ b/app/models/map.rb
@@ -18,11 +18,11 @@ class Map < ApplicationRecord
 
   # This method associates the attribute ":image" with a file attachment
   has_attached_file :screenshot,
-    styles: {
-      thumb: ['220x220#', :png]
-      #:full => ['940x630#', :png]
-    },
-    default_url: 'https://s3.amazonaws.com/metamaps-assets/site/missing-map-square.png'
+                    styles: {
+                      thumb: ['220x220#', :png]
+                      #:full => ['940x630#', :png]
+                    },
+                    default_url: 'https://s3.amazonaws.com/metamaps-assets/site/missing-map-square.png'
 
   validates :name, presence: true
   validates :arranged, inclusion: { in: [true, false] }
@@ -125,6 +125,6 @@ class Map < ApplicationRecord
   end
 
   def invited_text
-    self.name + ' - invited to edit'
+    name + ' - invited to edit'
   end
 end
diff --git a/app/models/webhooks/slack/base.rb b/app/models/webhooks/slack/base.rb
index 2274e32c..ba4e9ea5 100644
--- a/app/models/webhooks/slack/base.rb
+++ b/app/models/webhooks/slack/base.rb
@@ -14,9 +14,7 @@ Webhooks::Slack::Base = Struct.new(:webhook, :event) do
     'something'
   end
 
-  def channel
-    webhook.channel
-  end
+  delegate :channel, to: :webhook
 
   def attachments
     [{
diff --git a/app/policies/explore_policy.rb b/app/policies/explore_policy.rb
index b4d52fe5..ce17d4f4 100644
--- a/app/policies/explore_policy.rb
+++ b/app/policies/explore_policy.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class ExplorePolicy < ApplicationPolicy
   def active?
     true
diff --git a/app/policies/hack_policy.rb b/app/policies/hack_policy.rb
index b6fbf6ce..bdc9eaab 100644
--- a/app/policies/hack_policy.rb
+++ b/app/policies/hack_policy.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class HackPolicy < ApplicationPolicy
   def load_url_title?
     true
diff --git a/app/policies/map_policy.rb b/app/policies/map_policy.rb
index f670f59e..937d564c 100644
--- a/app/policies/map_policy.rb
+++ b/app/policies/map_policy.rb
@@ -16,7 +16,7 @@ class MapPolicy < ApplicationPolicy
   end
 
   def show?
-    record.permission.in?(['commons', 'public']) ||
+    record.permission.in?(%w(commons public)) ||
       record.collaborators.include?(user) ||
       record.user == user
   end
diff --git a/app/policies/topic_policy.rb b/app/policies/topic_policy.rb
index 64463b4a..bc80f657 100644
--- a/app/policies/topic_policy.rb
+++ b/app/policies/topic_policy.rb
@@ -22,7 +22,7 @@ class TopicPolicy < ApplicationPolicy
     if record.defer_to_map.present?
       map_policy.show?
     else
-      record.permission.in?(['commons', 'public']) || record.user == user
+      record.permission.in?(%w(commons public)) || record.user == user
     end
   end
 
diff --git a/app/services/notification_service.rb b/app/services/notification_service.rb
index 05a268f4..41202345 100644
--- a/app/services/notification_service.rb
+++ b/app/services/notification_service.rb
@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 class NotificationService
-
   def self.renderer
     renderer ||= ApplicationController.renderer.new(
       http_host: ENV['MAILER_DEFAULT_URL'],
diff --git a/config/initializers/doorkeeper.rb b/config/initializers/doorkeeper.rb
index 433b1c40..21b08bc2 100644
--- a/config/initializers/doorkeeper.rb
+++ b/config/initializers/doorkeeper.rb
@@ -9,20 +9,20 @@ Doorkeeper.configure do
       current_user
     else
       store_location_for(User, request.fullpath)
-      redirect_to(sign_in_url, notice: "Sign In to Connect")
+      redirect_to(sign_in_url, notice: 'Sign In to Connect')
     end
   end
 
   # If you want to restrict access to the web interface for adding oauth authorized applications,
   # you need to declare the block below.
   admin_authenticator do
-    if current_user && current_user.admin
+    if current_user&.admin
       current_user
     elsif current_user && !current_user.admin
-      redirect_to(root_url, notice: "Unauthorized")
+      redirect_to(root_url, notice: 'Unauthorized')
     else
       store_location_for(User, request.fullpath)
-      redirect_to(sign_in_url, notice: "Try signing in to do that")
+      redirect_to(sign_in_url, notice: 'Try signing in to do that')
     end
   end
 
diff --git a/config/initializers/rack-attack.rb b/config/initializers/rack-attack.rb
index 1cb90f0f..0fd76889 100644
--- a/config/initializers/rack-attack.rb
+++ b/config/initializers/rack-attack.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Rack::Attack
   Rack::Attack.cache.store = ActiveSupport::Cache::MemoryStore.new
 
@@ -11,10 +12,8 @@ class Rack::Attack
   # Throttle POST requests to /login by IP address
   #
   # Key: "rack::attack:#{Time.now.to_i/:period}:logins/ip:#{req.ip}"
-  throttle('logins/ip', :limit => 5, :period => 20.seconds) do |req|
-    if req.path == '/login' && req.post?
-      req.ip
-    end
+  throttle('logins/ip', limit: 5, period: 20.seconds) do |req|
+    req.ip if req.path == '/login' && req.post?
   end
 
   # Throttle POST requests to /login by email param
@@ -25,17 +24,17 @@ class Rack::Attack
   # throttle logins for another user and force their login requests to be
   # denied, but that's not very common and shouldn't happen to you. (Knock
   # on wood!)
-  throttle("logins/email", :limit => 5, :period => 20.seconds) do |req|
+  throttle('logins/email', limit: 5, period: 20.seconds) do |req|
     if req.path == '/login' && req.post?
       # return the email if present, nil otherwise
       req.params['email'].presence
     end
   end
 
-  throttle('load_url_title/req/5mins/ip', :limit => 300, :period => 5.minutes) do |req|
+  throttle('load_url_title/req/5mins/ip', limit: 300, period: 5.minutes) do |req|
     req.ip if req.path == 'hacks/load_url_title'
   end
-  throttle('load_url_title/req/1s/ip', :limit => 5, :period => 1.second) do |req|
+  throttle('load_url_title/req/1s/ip', limit: 5, period: 1.second) do |req|
     # If the return value is truthy, the cache key for the return value
     # is incremented and compared with the limit. In this case:
     #   "rack::attack:#{Time.now.to_i/1.second}:load_url_title/req/ip:#{req.ip}"
@@ -46,16 +45,16 @@ class Rack::Attack
   end
 
   self.throttled_response = lambda do |env|
-		now = Time.now
-		match_data = env['rack.attack.match_data']
+    now = Time.now
+    match_data = env['rack.attack.match_data']
     period = match_data[:period]
     limit = match_data[:limit]
 
-		headers = {
+    headers = {
       'X-RateLimit-Limit' => limit.to_s,
-			'X-RateLimit-Remaining' => '0',
-			'X-RateLimit-Reset' => (now + (period - now.to_i % period)).to_s
-		}
+      'X-RateLimit-Remaining' => '0',
+      'X-RateLimit-Reset' => (now + (period - now.to_i % period)).to_s
+    }
 
     [429, headers, ['']]
   end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 46d3db07..c4ada107 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -1,8 +1,4 @@
-# Sample localization file for English. Add more files in this directory for other locales.
-# See https://github.com/svenfuchs/rails-i18n/tree/master/rails%2Flocale for starting points.
-
 en:
-  activerecord:
-    attributes:
-      user:
-        joinedwithcode: "Access code"
+  mailboxer:
+    notification_mailer:
+      subject: "%{subject}"
diff --git a/spec/api/v2/mappings_api_spec.rb b/spec/api/v2/mappings_api_spec.rb
index 6f225c6a..f8854e91 100644
--- a/spec/api/v2/mappings_api_spec.rb
+++ b/spec/api/v2/mappings_api_spec.rb
@@ -18,7 +18,6 @@ RSpec.describe 'mappings API', type: :request do
   it 'GET /api/v2/mappings/:id' do
     get "/api/v2/mappings/#{mapping.id}", params: { access_token: token }
 
-
     expect(response).to have_http_status(:success)
     expect(response).to match_json_schema(:mapping)
     expect(JSON.parse(response.body)['data']['id']).to eq mapping.id
diff --git a/spec/api/v2/maps_api_spec.rb b/spec/api/v2/maps_api_spec.rb
index a7edeef2..fbf07903 100644
--- a/spec/api/v2/maps_api_spec.rb
+++ b/spec/api/v2/maps_api_spec.rb
@@ -1,4 +1,5 @@
-#t frozen_string_literal: true
+# frozen_string_literal: true
+# t frozen_string_literal: true
 require 'rails_helper'
 
 RSpec.describe 'maps API', type: :request do
@@ -35,7 +36,7 @@ RSpec.describe 'maps API', type: :request do
     expect(response).to match_json_schema(:map)
     expect(JSON.parse(response.body)['data']['id']).to eq map.id
   end
-  
+
   it 'POST /api/v2/maps' do
     post '/api/v2/maps', params: { map: map.attributes, access_token: token }
 
diff --git a/spec/api/v2/topics_api_spec.rb b/spec/api/v2/topics_api_spec.rb
index 31d93b87..ac2fb56a 100644
--- a/spec/api/v2/topics_api_spec.rb
+++ b/spec/api/v2/topics_api_spec.rb
@@ -18,7 +18,6 @@ RSpec.describe 'topics API', type: :request do
   it 'GET /api/v2/topics/:id' do
     get "/api/v2/topics/#{topic.id}"
 
-
     expect(response).to have_http_status(:success)
     expect(response).to match_json_schema(:topic)
     expect(JSON.parse(response.body)['data']['id']).to eq topic.id
diff --git a/spec/controllers/synapses_controller_spec.rb b/spec/controllers/synapses_controller_spec.rb
index 511971ad..7abeb2ee 100644
--- a/spec/controllers/synapses_controller_spec.rb
+++ b/spec/controllers/synapses_controller_spec.rb
@@ -53,9 +53,9 @@ RSpec.describe SynapsesController, type: :controller do
         expect(response.status).to eq 422
       end
       it 'does not create a synapse' do
-        expect {
+        expect do
           post :create, format: :json, params: { synapse: invalid_attributes }
-        }.to change {
+        end.to change {
           Synapse.count
         }.by 0
       end
diff --git a/spec/mailers/map_mailer_spec.rb b/spec/mailers/map_mailer_spec.rb
index 5fed48f5..a920746b 100644
--- a/spec/mailers/map_mailer_spec.rb
+++ b/spec/mailers/map_mailer_spec.rb
@@ -1,10 +1,11 @@
+# frozen_string_literal: true
 require 'rails_helper'
 
 RSpec.describe MapMailer, type: :mailer do
   describe 'access_request_email' do
-    let(:request) { create(:access_request) }
     let(:map) { create(:map) }
-    let(:mail) { described_class.access_request_email(request, map) }
+    let(:request) { create(:access_request, map: map) }
+    let(:mail) { described_class.access_request_email(request) }
 
     it { expect(mail.from).to eq ['team@metamaps.cc'] }
     it { expect(mail.to).to eq [map.user.email] }
diff --git a/spec/models/access_request_spec.rb b/spec/models/access_request_spec.rb
index 98490bf7..e8db280b 100644
--- a/spec/models/access_request_spec.rb
+++ b/spec/models/access_request_spec.rb
@@ -1,8 +1,7 @@
+# frozen_string_literal: true
 require 'rails_helper'
 
 RSpec.describe AccessRequest, type: :model do
-  include ActiveJob::TestHelper # enqueued_jobs
-
   let(:access_request) { create(:access_request) }
 
   describe 'approve' do
@@ -13,7 +12,7 @@ RSpec.describe AccessRequest, type: :model do
     it { expect(access_request.approved).to be true }
     it { expect(access_request.answered).to be true }
     it { expect(UserMap.count).to eq 1 }
-    it { expect(enqueued_jobs.count).to eq 1 }
+    it { expect(Mailboxer::Notification.count).to eq 1 }
   end
 
   describe 'deny' do
@@ -24,6 +23,6 @@ RSpec.describe AccessRequest, type: :model do
     it { expect(access_request.approved).to be false }
     it { expect(access_request.answered).to be true }
     it { expect(UserMap.count).to eq 0 }
-    it { expect(enqueued_jobs.count).to eq 0 }
+    it { expect(Mailboxer::Notification.count).to eq 0 }
   end
 end