diff --git a/app/models/concerns/has_dns_checks.rb b/app/models/concerns/has_dns_checks.rb
index 3147e89..4ec4ad7 100644
--- a/app/models/concerns/has_dns_checks.rb
+++ b/app/models/concerns/has_dns_checks.rb
@@ -5,7 +5,7 @@ require "resolv"
 module HasDNSChecks
 
   def dns_ok?
-    spf_status == "OK" && dkim_status == "OK" && ["OK", "Missing"].include?(mx_status) && ["OK", "Missing"].include?(return_path_status)
+    spf_status == "OK" && dkim_status == "OK" && %w[OK Missing].include?(mx_status) && %w[OK Missing].include?(return_path_status)
   end
 
   def dns_checked?
diff --git a/app/models/credential.rb b/app/models/credential.rb
index 2c37593..18e3266 100644
--- a/app/models/credential.rb
+++ b/app/models/credential.rb
@@ -23,7 +23,7 @@ class Credential < ApplicationRecord
 
   belongs_to :server
 
-  TYPES = ["SMTP", "API", "SMTP-IP"].freeze
+  TYPES = %w[SMTP API SMTP-IP].freeze
 
   validates :key, presence: true, uniqueness: { case_sensitive: false }
   validates :type, inclusion: { in: TYPES }
diff --git a/app/models/domain.rb b/app/models/domain.rb
index ba61992..bcfb263 100644
--- a/app/models/domain.rb
+++ b/app/models/domain.rb
@@ -44,8 +44,8 @@ class Domain < ApplicationRecord
 
   include HasDNSChecks
 
-  VERIFICATION_EMAIL_ALIASES = ["webmaster", "postmaster", "admin", "administrator", "hostmaster"].freeze
-  VERIFICATION_METHODS = ["DNS", "Email"].freeze
+  VERIFICATION_EMAIL_ALIASES = %w[webmaster postmaster admin administrator hostmaster].freeze
+  VERIFICATION_METHODS = %w[DNS Email].freeze
 
   belongs_to :server, optional: true
   belongs_to :owner, optional: true, polymorphic: true
diff --git a/app/models/http_endpoint.rb b/app/models/http_endpoint.rb
index ff33a24..8cd9044 100644
--- a/app/models/http_endpoint.rb
+++ b/app/models/http_endpoint.rb
@@ -31,8 +31,8 @@ class HTTPEndpoint < ApplicationRecord
   has_many :routes, as: :endpoint
   has_many :additional_route_endpoints, dependent: :destroy, as: :endpoint
 
-  ENCODINGS = ["BodyAsJSON", "FormData"].freeze
-  FORMATS = ["Hash", "RawMessage"].freeze
+  ENCODINGS = %w[BodyAsJSON FormData].freeze
+  FORMATS = %w[Hash RawMessage].freeze
 
   before_destroy :update_routes
 
diff --git a/app/models/organization.rb b/app/models/organization.rb
index 57e16cd..60841dc 100644
--- a/app/models/organization.rb
+++ b/app/models/organization.rb
@@ -25,7 +25,7 @@
 
 class Organization < ApplicationRecord
 
-  RESERVED_PERMALINKS = ["new", "edit", "remove", "delete", "destroy", "admin", "mail", "org", "server"].freeze
+  RESERVED_PERMALINKS = %w[new edit remove delete destroy admin mail org server].freeze
 
   INITIAL_QUOTA = 10
   INITIAL_SUPER_QUOTA = 10_000
diff --git a/app/models/route.rb b/app/models/route.rb
index cd837d0..9d59f5c 100644
--- a/app/models/route.rb
+++ b/app/models/route.rb
@@ -24,9 +24,9 @@
 
 class Route < ApplicationRecord
 
-  MODES = ["Endpoint", "Accept", "Hold", "Bounce", "Reject"].freeze
-  SPAM_MODES = ["Mark", "Quarantine", "Fail"].freeze
-  ENDPOINT_TYPES = ["SMTPEndpoint", "HTTPEndpoint", "AddressEndpoint"].freeze
+  MODES = %w[Endpoint Accept Hold Bounce Reject].freeze
+  SPAM_MODES = %w[Mark Quarantine Fail].freeze
+  ENDPOINT_TYPES = %w[SMTPEndpoint HTTPEndpoint AddressEndpoint].freeze
 
   include HasUUID
 
diff --git a/app/models/server.rb b/app/models/server.rb
index c2f39a6..e14b53c 100644
--- a/app/models/server.rb
+++ b/app/models/server.rb
@@ -43,8 +43,8 @@
 
 class Server < ApplicationRecord
 
-  RESERVED_PERMALINKS = ["new", "all", "search", "stats", "edit", "manage", "delete", "destroy", "remove"].freeze
-  MODES = ["Live", "Development"].freeze
+  RESERVED_PERMALINKS = %w[new all search stats edit manage delete destroy remove].freeze
+  MODES = %w[Live Development].freeze
 
   include HasUUID
   include HasSoftDestroy
diff --git a/app/models/smtp_endpoint.rb b/app/models/smtp_endpoint.rb
index 84c40aa..b063f80 100644
--- a/app/models/smtp_endpoint.rb
+++ b/app/models/smtp_endpoint.rb
@@ -26,7 +26,7 @@ class SMTPEndpoint < ApplicationRecord
   has_many :routes, as: :endpoint
   has_many :additional_route_endpoints, dependent: :destroy, as: :endpoint
 
-  SSL_MODES = ["None", "Auto", "STARTTLS", "TLS"].freeze
+  SSL_MODES = %w[None Auto STARTTLS TLS].freeze
 
   before_destroy :update_routes
 
diff --git a/app/models/webhook_event.rb b/app/models/webhook_event.rb
index a54da56..29295e7 100644
--- a/app/models/webhook_event.rb
+++ b/app/models/webhook_event.rb
@@ -16,15 +16,15 @@
 
 class WebhookEvent < ApplicationRecord
 
-  EVENTS = [
-    "MessageSent",
-    "MessageDelayed",
-    "MessageDeliveryFailed",
-    "MessageHeld",
-    "MessageBounced",
-    "MessageLinkClicked",
-    "MessageLoaded",
-    "DomainDNSError"
+  EVENTS = %w[
+    MessageSent
+    MessageDelayed
+    MessageDeliveryFailed
+    MessageHeld
+    MessageBounced
+    MessageLinkClicked
+    MessageLoaded
+    DomainDNSError
   ].freeze
 
   belongs_to :webhook
diff --git a/lib/postal/message_db/database.rb b/lib/postal/message_db/database.rb
index 97376d7..f61ffbe 100644
--- a/lib/postal/message_db/database.rb
+++ b/lib/postal/message_db/database.rb
@@ -160,7 +160,7 @@ module Postal
         end
         if options[:order]
           direction = (options[:direction] || "ASC").upcase
-          raise Postal::Error, "Invalid direction #{options[:direction]}" unless ["ASC", "DESC"].include?(direction)
+          raise Postal::Error, "Invalid direction #{options[:direction]}" unless %w[ASC DESC].include?(direction)
 
           sql_query << " ORDER BY `#{options[:order]}` #{direction}"
         end
diff --git a/lib/postal/message_db/provisioner.rb b/lib/postal/message_db/provisioner.rb
index 31619db..743bb84 100644
--- a/lib/postal/message_db/provisioner.rb
+++ b/lib/postal/message_db/provisioner.rb
@@ -70,9 +70,9 @@ module Postal
       # environment and can be quite dangerous in production.
       #
       def clean
-        ["clicks", "deliveries", "links", "live_stats", "loads", "messages",
-         "raw_message_sizes", "spam_checks", "stats_daily", "stats_hourly",
-         "stats_monthly", "stats_yearly", "suppressions", "webhook_requests"].each do |table|
+        %w[clicks deliveries links live_stats loads messages
+         raw_message_sizes spam_checks stats_daily stats_hourly
+         stats_monthly stats_yearly suppressions webhook_requests].each do |table|
           @database.query("TRUNCATE `#{@database.database_name}`.`#{table}`")
         end
       end