diff --git a/app/models/domain.rb b/app/models/domain.rb
index a248546..ae0b416 100644
--- a/app/models/domain.rb
+++ b/app/models/domain.rb
@@ -85,7 +85,7 @@ class Domain < ApplicationRecord
 
   def parent_domains
     parts = name.split(".")
-    parts[0, parts.size - 1].each_with_index.map do |p, i|
+    parts[0, parts.size - 1].each_with_index.map do |_, i|
       parts[i..-1].join(".")
     end
   end
diff --git a/app/models/outgoing_message_prototype.rb b/app/models/outgoing_message_prototype.rb
index a54a148..d1bff40 100644
--- a/app/models/outgoing_message_prototype.rb
+++ b/app/models/outgoing_message_prototype.rb
@@ -137,7 +137,7 @@ class OutgoingMessagePrototype
     end
 
     if attachments.present?
-      attachments.each_with_index do |attachment, index|
+      attachments.each do |attachment|
         if attachment[:name].blank?
           @errors << "AttachmentMissingName" unless @errors.include?("AttachmentMissingName")
         elsif attachment[:data].blank?
diff --git a/app/models/route.rb b/app/models/route.rb
index dbc653b..0561551 100644
--- a/app/models/route.rb
+++ b/app/models/route.rb
@@ -117,7 +117,7 @@ class Route < ApplicationRecord
         if route.save
           seen << route.id
         else
-          route.errors.each do |field, message|
+          route.errors.each do |_, message|
             errors.add :base, message
           end
           raise ActiveRecord::RecordInvalid
diff --git a/app/models/server.rb b/app/models/server.rb
index 63439b6..33a72ca 100644
--- a/app/models/server.rb
+++ b/app/models/server.rb
@@ -157,7 +157,7 @@ class Server < ApplicationRecord
       time = Time.now.utc
       total_outgoing = 0.0
       total_bounces = 0.0
-      message_db.statistics.get(:daily, [:outgoing, :bounces], time, 30).each do |date, stat|
+      message_db.statistics.get(:daily, [:outgoing, :bounces], time, 30).each do |_, stat|
         total_outgoing += stat[:outgoing]
         total_bounces += stat[:bounces]
       end
diff --git a/config/application.rb b/config/application.rb
index a7879aa..d0fb313 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -32,7 +32,7 @@ module Postal
     config.eager_load_paths << Rails.root.join("lib")
 
     # Disable field_with_errors
-    config.action_view.field_error_proc = proc { |t, i| t }
+    config.action_view.field_error_proc = proc { |t, _| t }
 
     # Load the tracking server middleware
     require "postal/tracking_middleware"
diff --git a/lib/postal/message_db/message.rb b/lib/postal/message_db/message.rb
index ce7a72a..df778d0 100644
--- a/lib/postal/message_db/message.rb
+++ b/lib/postal/message_db/message.rb
@@ -553,14 +553,14 @@ module Postal
       private
 
       def _update
-        @database.update("messages", @attributes.reject { |k, v| k == :id }, where: { id: @attributes["id"] })
+        @database.update("messages", @attributes.reject { |k, _| k == :id }, where: { id: @attributes["id"] })
       end
 
       def _create
         self.timestamp = Time.now.to_f if timestamp.blank?
         self.status = "Pending" if status.blank?
         self.token = Nifty::Utils::RandomString.generate(length: 12) if token.blank?
-        last_id = @database.insert("messages", @attributes.reject { |k, v| k == :id })
+        last_id = @database.insert("messages", @attributes.reject { |k, _| k == :id })
         @attributes["id"] = last_id
         @database.statistics.increment_all(timestamp, scope)
         Statistic.global.increment!(:total_messages)
diff --git a/lib/postal/smtp_server/client.rb b/lib/postal/smtp_server/client.rb
index 6e8514d..78e9651 100644
--- a/lib/postal/smtp_server/client.rb
+++ b/lib/postal/smtp_server/client.rb
@@ -188,7 +188,7 @@ module Postal
           authenticate(password)
         end
 
-        username_handler = proc do |data|
+        username_handler = proc do
           @proc = password_handler
           @password_expected_next = true
           "334 UGFzc3dvcmQ6" # "Password:"
diff --git a/spec/lib/postal/message_db/connection_pool_spec.rb b/spec/lib/postal/message_db/connection_pool_spec.rb
index 506359a..cbc730b 100644
--- a/spec/lib/postal/message_db/connection_pool_spec.rb
+++ b/spec/lib/postal/message_db/connection_pool_spec.rb
@@ -26,7 +26,7 @@ describe Postal::MessageDB::ConnectionPool do
 
     it "checks in a connection if theres an error in the block" do
       expect do
-        pool.use do |c|
+        pool.use do
           raise StandardError
         end
       end.to raise_error StandardError