diff --git a/.deepsource.toml b/.deepsource.toml
new file mode 100644
index 000000000..73d38901c
--- /dev/null
+++ b/.deepsource.toml
@@ -0,0 +1,18 @@
+version = 1
+
+test_patterns = ["/app/javascript/mastodon/**/__tests__/**"]
+
+[[analyzers]]
+name = "ruby"
+enabled = true
+
+[[analyzers]]
+name = "javascript"
+enabled = true
+
+  [analyzers.meta]
+  environment = [
+    "nodejs",
+    "browser",
+    "jest"
+  ]
diff --git a/config/initializers/fast_blank.rb b/config/initializers/fast_blank.rb
index 174ea7664..f0b7cac78 100644
--- a/config/initializers/fast_blank.rb
+++ b/config/initializers/fast_blank.rb
@@ -1,5 +1,5 @@
 if String.method_defined?(:blank_as?)
   class String
-    alias_method :blank?, :blank_as?
+    alias blank? blank_as?
   end
 end
diff --git a/config/initializers/simple_form.rb b/config/initializers/simple_form.rb
index 3dc48ef08..3a2097d2f 100644
--- a/config/initializers/simple_form.rb
+++ b/config/initializers/simple_form.rb
@@ -1,7 +1,7 @@
 # Use this setup block to configure all options available in SimpleForm.
 
 module AppendComponent
-  def append(wrapper_options = nil)
+  def append(_wrapper_options = nil)
     @append ||= begin
       options[:append].to_s.html_safe if options[:append].present?
     end
@@ -9,7 +9,7 @@ module AppendComponent
 end
 
 module RecommendedComponent
-  def recommended(wrapper_options = nil)
+  def recommended(_wrapper_options = nil)
     return unless options[:recommended]
     options[:label_text] = ->(raw_label_text, _required_label_text, _label_present) { safe_join([raw_label_text, ' ', content_tag(:span, I18n.t('simple_form.recommended'), class: 'recommended')]) }
     nil
diff --git a/config/initializers/twitter_regex.rb b/config/initializers/twitter_regex.rb
index 7f99a0005..aca85dd43 100644
--- a/config/initializers/twitter_regex.rb
+++ b/config/initializers/twitter_regex.rb
@@ -75,7 +75,7 @@ module Twitter
     # XMPP or magnet URIs an empty array will be returned.
     #
     # If a block is given then it will be called for each XMPP URI.
-    def extract_extra_uris_with_indices(text, options = {}) # :yields: uri, start, end
+    def extract_extra_uris_with_indices(text, _options = {}) # :yields: uri, start, end
       return [] unless text && text.index(":")
       urls = []
 
diff --git a/lib/json_ld/identity.rb b/lib/json_ld/identity.rb
index 4fb3f8e9d..f41899150 100644
--- a/lib/json_ld/identity.rb
+++ b/lib/json_ld/identity.rb
@@ -1,4 +1,3 @@
-# -*- encoding: utf-8 -*-
 # frozen_string_literal: true
 # This file generated automatically from http://w3id.org/identity/v1
 require 'json/ld'
diff --git a/lib/json_ld/security.rb b/lib/json_ld/security.rb
index a6fbce95f..ef5391340 100644
--- a/lib/json_ld/security.rb
+++ b/lib/json_ld/security.rb
@@ -1,4 +1,3 @@
-# -*- encoding: utf-8 -*-
 # frozen_string_literal: true
 # This file generated automatically from http://w3id.org/security/v1
 require 'json/ld'
diff --git a/lib/mastodon/email_domain_blocks_cli.rb b/lib/mastodon/email_domain_blocks_cli.rb
index 55a637d68..f79df302a 100644
--- a/lib/mastodon/email_domain_blocks_cli.rb
+++ b/lib/mastodon/email_domain_blocks_cli.rb
@@ -113,7 +113,7 @@ module Mastodon
         result = entry.destroy
 
         if result
-          processed += 1 + children_count
+          processed += children_count + 1
         else
           say("#{domain} could not be unblocked.", :red)
           failed += 1
diff --git a/lib/paperclip/color_extractor.rb b/lib/paperclip/color_extractor.rb
index a70a3d21f..d3b8e1022 100644
--- a/lib/paperclip/color_extractor.rb
+++ b/lib/paperclip/color_extractor.rb
@@ -55,7 +55,7 @@ module Paperclip
       # If we don't have enough colors for accent and foreground, generate
       # new ones by manipulating the background color
       (2 - foreground_colors.size).times do |i|
-        foreground_colors << lighten_or_darken(background_color, 35 + (15 * i))
+        foreground_colors << lighten_or_darken(background_color, 35 + (i * 15))
       end
 
       # We want the color with the highest contrast to background to be the foreground one,
@@ -147,7 +147,7 @@ module Paperclip
         g = l.to_f
         b = l.to_f # achromatic
       else
-        q = l < 0.5 ? l * (1 + s) : l + s - l * s
+        q = l < 0.5 ? l * (s + 1) : l + s - l * s
         p = 2 * l - q
         r = hue_to_rgb(p, q, h + 1 / 3.0)
         g = hue_to_rgb(p, q, h)
diff --git a/spec/lib/activitypub/linked_data_signature_spec.rb b/spec/lib/activitypub/linked_data_signature_spec.rb
index 1f413eec9..2222c46fb 100644
--- a/spec/lib/activitypub/linked_data_signature_spec.rb
+++ b/spec/lib/activitypub/linked_data_signature_spec.rb
@@ -81,6 +81,6 @@ RSpec.describe ActivityPub::LinkedDataSignature do
     options_hash   = Digest::SHA256.hexdigest(canonicalize(options.merge('@context' => ActivityPub::LinkedDataSignature::CONTEXT)))
     document_hash  = Digest::SHA256.hexdigest(canonicalize(document))
     to_be_verified = options_hash + document_hash
-    Base64.strict_encode64(from_account.keypair.sign(OpenSSL::Digest::SHA256.new, to_be_verified))
+    Base64.strict_encode64(from_account.keypair.sign(OpenSSL::Digest.new('SHA256'), to_be_verified))
   end
 end