diff --git a/.github/dependabot.yml b/.github/dependabot.yml
deleted file mode 100644
index c496bc7..0000000
--- a/.github/dependabot.yml
+++ /dev/null
@@ -1,11 +0,0 @@
-# To get started with Dependabot version updates, you'll need to specify which
-# package ecosystems to update and where the package manifests are located.
-# Please see the documentation for all configuration options:
-# https://docs.github.com/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
-
-version: 2
-updates:
-  - package-ecosystem: "bundler" # See documentation for possible values
-    directory: "/" # Location of package manifests
-    schedule:
-      interval: "weekly"
diff --git a/.github/stale.yml b/.github/stale.yml
deleted file mode 100644
index dc90e5a..0000000
--- a/.github/stale.yml
+++ /dev/null
@@ -1,17 +0,0 @@
-# Number of days of inactivity before an issue becomes stale
-daysUntilStale: 60
-# Number of days of inactivity before a stale issue is closed
-daysUntilClose: 7
-# Issues with these labels will never be considered stale
-exemptLabels:
-  - pinned
-  - security
-# Label to use when marking an issue as stale
-staleLabel: wontfix
-# Comment to post when marking an issue as stale. Set to `false` to disable
-markComment: >
-  This issue has been automatically marked as stale because it has not had
-  recent activity. It will be closed if no further activity occurs. Thank you
-  for your contributions.
-# Comment to post when closing a stale issue. Set to `false` to disable
-closeComment: false
diff --git a/.rubocop.yml b/.rubocop.yml
index 0e0a2af..2299bcc 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,3 +1,6 @@
+inherit_gem:
+  rubocop-shopify: rubocop.yml
+
 inherit_from: ".rubocop_todo.yml"
 
 require:
diff --git a/Gemfile b/Gemfile
index 2ed1724..6cab696 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,34 +1,34 @@
 # frozen_string_literal: true
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-ruby File.read('.ruby-version').chomp
+ruby File.read(".ruby-version").chomp
 
-gem 'money'
-gem 'oj'
-gem 'ox'
-gem 'rack-contrib'
-gem 'rack-cors'
-gem 'rake'
-gem 'roda'
-gem 'rufus-scheduler'
-gem 'sequel_pg'
-gem 'unicorn'
+gem "money"
+gem "oj"
+gem "ox"
+gem "rack-contrib"
+gem "rack-cors"
+gem "rake"
+gem "roda"
+gem "rufus-scheduler"
+gem "sequel_pg"
+gem "unicorn"
 
 group :development, :test do
-  gem 'pry-byebug'
-  gem 'rubocop-minitest'
-  gem 'rubocop-performance'
-  gem 'rubocop-rake'
-  gem 'rubocop-sequel'
+  gem "rubocop-minitest"
+  gem "rubocop-performance"
+  gem "rubocop-rake"
+  gem "rubocop-sequel"
+  gem "rubocop-shopify"
 end
 
 group :test do
-  gem 'minitest'
-  gem 'minitest-around'
-  gem 'minitest-focus'
-  gem 'rack-test'
-  gem 'simplecov'
-  gem 'vcr'
-  gem 'webmock'
+  gem "minitest"
+  gem "minitest-around"
+  gem "minitest-focus"
+  gem "rack-test"
+  gem "simplecov"
+  gem "vcr"
+  gem "webmock"
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index ea9714f..2e7f3d2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,8 +6,6 @@ GEM
     ast (2.4.2)
     base64 (0.2.0)
     bigdecimal (3.1.8)
-    byebug (11.1.3)
-    coderay (1.1.3)
     concurrent-ruby (1.3.4)
     crack (1.0.0)
       bigdecimal
@@ -18,13 +16,12 @@ GEM
     fugit (1.11.1)
       et-orbi (~> 1, >= 1.2.11)
       raabro (~> 1.4)
-    hashdiff (1.1.1)
+    hashdiff (1.1.2)
     i18n (1.14.6)
       concurrent-ruby (~> 1.0)
     json (2.8.2)
     kgio (2.11.4)
     language_server-protocol (3.17.0.3)
-    method_source (1.1.0)
     minitest (5.25.1)
     minitest-around (0.5.0)
       minitest (~> 5.0)
@@ -35,19 +32,13 @@ GEM
     oj (3.16.7)
       bigdecimal (>= 3.0)
       ostruct (>= 0.2)
-    ostruct (0.6.0)
+    ostruct (0.6.1)
     ox (2.14.18)
     parallel (1.26.3)
     parser (3.3.6.0)
       ast (~> 2.4.1)
       racc
-    pg (1.5.8)
-    pry (0.14.2)
-      coderay (~> 1.1)
-      method_source (~> 1.0)
-    pry-byebug (3.10.1)
-      byebug (~> 11.0)
-      pry (>= 0.13, < 0.15)
+    pg (1.5.9)
     public_suffix (6.0.1)
     raabro (1.4.0)
     racc (1.8.1)
@@ -87,10 +78,12 @@ GEM
       rubocop (~> 1.0)
     rubocop-sequel (0.3.7)
       rubocop (~> 1.0)
+    rubocop-shopify (2.15.1)
+      rubocop (~> 1.51)
     ruby-progressbar (1.13.0)
     rufus-scheduler (3.9.2)
       fugit (~> 1.1, >= 1.11.1)
-    sequel (5.85.0)
+    sequel (5.86.0)
       bigdecimal
     sequel_pg (1.17.1)
       pg (>= 0.18.0, != 1.2.0)
@@ -124,7 +117,6 @@ DEPENDENCIES
   money
   oj
   ox
-  pry-byebug
   rack-contrib
   rack-cors
   rack-test
@@ -134,6 +126,7 @@ DEPENDENCIES
   rubocop-performance
   rubocop-rake
   rubocop-sequel
+  rubocop-shopify
   rufus-scheduler
   sequel_pg
   simplecov
diff --git a/Rakefile b/Rakefile
index 358da59..f47a29f 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,3 +1,3 @@
 # frozen_string_literal: true
 
-Dir.glob('lib/tasks/*.rake').each { |r| import r }
+Dir.glob("lib/tasks/*.rake").each { |r| import r }
diff --git a/bin/schedule b/bin/schedule
index aea3f7e..7c5e64d 100755
--- a/bin/schedule
+++ b/bin/schedule
@@ -1,12 +1,12 @@
 #!/usr/bin/env ruby
 # frozen_string_literal: true
 
-require 'rufus-scheduler'
+require "rufus-scheduler"
 
 scheduler = Rufus::Scheduler.new
 
-scheduler.cron '*/30 15,16,17 * * 1-5' do
-  `rake rates:current`
+scheduler.cron("*/30 15,16,17 * * 1-5") do
+  %x(rake rates:current)
 end
 
 scheduler.join
diff --git a/config.ru b/config.ru
index c7015e8..b9e3011 100644
--- a/config.ru
+++ b/config.ru
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require './config/environment'
-require 'web/server'
+require "./config/environment"
+require "web/server"
 
 run Web::Server.freeze.app
diff --git a/config/app.rb b/config/app.rb
index d3921c3..0902e4b 100644
--- a/config/app.rb
+++ b/config/app.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require 'pathname'
+require "pathname"
 
 # Encapsulates app configuration
 module App
   class << self
     def env
-      ENV['APP_ENV'] || 'development'
+      ENV["APP_ENV"] || "development"
     end
 
     def root
-      Pathname.new(File.expand_path('..', __dir__))
+      Pathname.new(File.expand_path("..", __dir__))
     end
   end
 end
diff --git a/config/environment.rb b/config/environment.rb
index 578fb8c..b43fb20 100644
--- a/config/environment.rb
+++ b/config/environment.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
-require_relative 'app'
-$LOAD_PATH << App.root.join('lib')
-Dir[App.root.join('config/initializers/*.rb')].each { |f| require f }
+require_relative "app"
+$LOAD_PATH << App.root.join("lib")
+Dir[App.root.join("config/initializers/*.rb")].each { |f| require f }
diff --git a/config/initializers/sequel.rb b/config/initializers/sequel.rb
index c158846..08672e6 100644
--- a/config/initializers/sequel.rb
+++ b/config/initializers/sequel.rb
@@ -1,10 +1,10 @@
 # frozen_string_literal: true
 
-require 'pg'
-require 'sequel'
+require "pg"
+require "sequel"
 
-Sequel.extension :pg_json_ops
+Sequel.extension(:pg_json_ops)
 Sequel.single_threaded = true
-Sequel.connect(ENV['DATABASE_URL'] ||
-               "postgres://localhost:#{ENV.fetch('PGPORT', nil)}/frankfurter_#{App.env}")
-      .extension :pg_json
+Sequel.connect(ENV["DATABASE_URL"] ||
+               "postgres://localhost:#{ENV.fetch("PGPORT", nil)}/frankfurter_#{App.env}")
+  .extension(:pg_json)
diff --git a/config/unicorn.rb b/config/unicorn.rb
index 41a6ea8..ea30450 100644
--- a/config/unicorn.rb
+++ b/config/unicorn.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
-`rake db:prepare`
+%x(rake db:prepare)
 
-worker_process_count = (ENV['WORKER_PROCESSES'] || 4).to_i
+worker_process_count = (ENV["WORKER_PROCESSES"] || 4).to_i
 
 preload_app true
 worker_processes worker_process_count
@@ -12,7 +12,7 @@ initialized = false
 before_fork do |_server, _worker|
   Sequel::DATABASES.each(&:disconnect)
   unless initialized
-    require 'scheduler/daemon'
+    require "scheduler/daemon"
     Scheduler::Daemon.start
     initialized = true
   end
diff --git a/db/migrate/001_create_currencies.rb b/db/migrate/001_create_currencies.rb
index 80a5d55..bec0a4f 100644
--- a/db/migrate/001_create_currencies.rb
+++ b/db/migrate/001_create_currencies.rb
@@ -7,7 +7,7 @@ Sequel.migration do
       String  :iso_code
       Float   :rate
 
-      index %i[date iso_code], unique: true
+      index [:date, :iso_code], unique: true
     end
   end
 
diff --git a/db/migrate/002_denormalise_currencies.rb b/db/migrate/002_denormalise_currencies.rb
index 3aeb767..6722fc7 100644
--- a/db/migrate/002_denormalise_currencies.rb
+++ b/db/migrate/002_denormalise_currencies.rb
@@ -15,7 +15,7 @@ Sequel.migration do
       date    :date
       string  :iso_code
       float   :rate
-      index %i[date iso_code], unique: true
+      index [:date, :iso_code], unique: true
     end
     drop_table :days
   end
diff --git a/lib/bank.rb b/lib/bank.rb
index bc56e95..bce79f3 100644
--- a/lib/bank.rb
+++ b/lib/bank.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-require 'day'
-require 'bank/feed'
+require "day"
+require "bank/feed"
 
 module Bank
   class << self
diff --git a/lib/bank/feed.rb b/lib/bank/feed.rb
index ca79da6..6d5f315 100644
--- a/lib/bank/feed.rb
+++ b/lib/bank/feed.rb
@@ -1,36 +1,38 @@
 # frozen_string_literal: true
 
-require 'net/http'
-require 'ox'
+require "net/http"
+require "ox"
 
 module Bank
   class Feed
     include Enumerable
 
-    def self.current
-      url = URI('https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml')
-      xml = Net::HTTP.get(url)
+    class << self
+      def current
+        url = URI("https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml")
+        xml = Net::HTTP.get(url)
 
-      new(xml)
-    end
+        new(xml)
+      end
 
-    def self.ninety_days
-      url = URI('https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist-90d.xml')
-      xml = Net::HTTP.get(url)
+      def ninety_days
+        url = URI("https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist-90d.xml")
+        xml = Net::HTTP.get(url)
 
-      new(xml)
-    end
+        new(xml)
+      end
 
-    def self.historical
-      url = URI('https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist.xml')
-      xml = Net::HTTP.get(url)
+      def historical
+        url = URI("https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist.xml")
+        xml = Net::HTTP.get(url)
 
-      new(xml)
-    end
+        new(xml)
+      end
 
-    def self.saved_data
-      xml = File.read(File.join(__dir__, 'eurofxref-hist.xml'))
-      new(xml)
+      def saved_data
+        xml = File.read(File.join(__dir__, "eurofxref-hist.xml"))
+        new(xml)
+      end
     end
 
     def initialize(xml)
@@ -38,8 +40,8 @@ module Bank
     end
 
     def each
-      @document.locate('gesmes:Envelope/Cube/Cube').each do |day|
-        yield(date: Date.parse(day['time']),
+      @document.locate("gesmes:Envelope/Cube/Cube").each do |day|
+        yield(date: Date.parse(day["time"]),
               rates: day.nodes.each_with_object({}) do |currency, rates|
                 rates[currency[:currency]] = Float(currency[:rate])
               end)
diff --git a/lib/currency.rb b/lib/currency.rb
index a52fbdc..2037858 100644
--- a/lib/currency.rb
+++ b/lib/currency.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-require 'day'
-require 'forwardable'
+require "day"
+require "forwardable"
 
 class Currency < Sequel::Model(Day.currencies)
   class << self
@@ -17,7 +17,7 @@ class Currency < Sequel::Model(Day.currencies)
 
     def between(interval)
       case interval.last - interval.first
-      when 366.. then super.sample('week')
+      when 366.. then super.sample("week")
       else super
       end
     end
diff --git a/lib/currency_names.rb b/lib/currency_names.rb
index d5c7e9b..44e29bc 100644
--- a/lib/currency_names.rb
+++ b/lib/currency_names.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-require 'currency'
-require 'money/currency'
+require "currency"
+require "money/currency"
 
 class CurrencyNames
   def cache_key
@@ -17,7 +17,7 @@ class CurrencyNames
   private
 
   def iso_codes
-    currencies.map(&:iso_code).append('EUR').sort
+    currencies.map(&:iso_code).append("EUR").sort
   end
 
   def currencies
diff --git a/lib/day.rb b/lib/day.rb
index aa8de00..6e176a0 100644
--- a/lib/day.rb
+++ b/lib/day.rb
@@ -3,7 +3,7 @@
 class Day < Sequel::Model
   dataset_module do
     def latest(date = Date.today)
-      where(date: select(:date).where(Sequel.lit('date <= ?', date))
+      where(date: select(:date).where(Sequel.lit("date <= ?", date))
                                .order(Sequel.desc(:date))
                                .limit(1))
     end
@@ -13,9 +13,11 @@ class Day < Sequel::Model
     end
 
     def currencies
-      select(:date,
-             Sequel.lit('rates.key').as(:iso_code),
-             Sequel.lit('rates.value::text::float').as(:rate))
+      select(
+        :date,
+        Sequel.lit("rates.key").as(:iso_code),
+        Sequel.lit("rates.value::text::float").as(:rate),
+      )
         .join(Sequel.function(:jsonb_each, :rates).lateral.as(:rates), true)
     end
   end
diff --git a/lib/query.rb b/lib/query.rb
index da980df..a155612 100644
--- a/lib/query.rb
+++ b/lib/query.rb
@@ -1,8 +1,10 @@
 # frozen_string_literal: true
 
 class Query
-  def self.build(params)
-    new(params).to_h
+  class << self
+    def build(params)
+      new(params).to_h
+    end
   end
 
   def initialize(params = {})
@@ -20,7 +22,7 @@ class Query
   end
 
   def symbols
-    @params.values_at(:to, :symbols).compact.first&.upcase&.split(',')
+    @params.values_at(:to, :symbols).compact.first&.upcase&.split(",")
   end
 
   def date
diff --git a/lib/quote.rb b/lib/quote.rb
index 359cf45..c92aadc 100644
--- a/lib/quote.rb
+++ b/lib/quote.rb
@@ -1,4 +1,4 @@
 # frozen_string_literal: true
 
-require 'quote/end_of_day'
-require 'quote/interval'
+require "quote/end_of_day"
+require "quote/interval"
diff --git a/lib/quote/base.rb b/lib/quote/base.rb
index 83a0ca1..765e2fe 100644
--- a/lib/quote/base.rb
+++ b/lib/quote/base.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require 'roundable'
+require "roundable"
 
 module Quote
   class Base
     include Roundable
 
-    DEFAULT_BASE = 'EUR'
+    DEFAULT_BASE = "EUR"
 
     attr_reader :amount, :base, :date, :symbols, :result
 
-    def initialize(date:, amount: 1.0, base: 'EUR', symbols: nil)
+    def initialize(date:, amount: 1.0, base: "EUR", symbols: nil)
       @date = date
       @amount = amount
       @base = base
@@ -29,7 +29,7 @@ module Quote
     end
 
     def must_rebase?
-      base != 'EUR'
+      base != "EUR"
     end
 
     def formatted
@@ -64,16 +64,16 @@ module Quote
 
     def rebase_rates
       result.each do |date, rates|
-        rates['EUR'] = amount if symbols.nil? || symbols.include?('EUR')
+        rates["EUR"] = amount if symbols.nil? || symbols.include?("EUR")
         divisor = rates.delete(base)
         if divisor.nil? || rates.empty?
           result.delete(date)
         else
           result[date] = rates.sort
-                              .map! do |iso_code, rate|
-                                [iso_code, round(amount * rate / divisor)]
-                              end
-                              .to_h
+            .map! do |iso_code, rate|
+            [iso_code, round(amount * rate / divisor)]
+          end
+            .to_h
         end
       end
     end
diff --git a/lib/quote/end_of_day.rb b/lib/quote/end_of_day.rb
index 20adf4e..f3d24dc 100644
--- a/lib/quote/end_of_day.rb
+++ b/lib/quote/end_of_day.rb
@@ -1,15 +1,17 @@
 # frozen_string_literal: true
 
-require 'quote/base'
-require 'digest'
+require "quote/base"
+require "digest"
 
 module Quote
   class EndOfDay < Base
     def formatted
-      { amount:,
+      {
+        amount:,
         base:,
         date: result.keys.first,
-        rates: result.values.first }
+        rates: result.values.first,
+      }
     end
 
     def cache_key
@@ -21,7 +23,7 @@ module Quote
     private
 
     def fetch_data
-      require 'currency'
+      require "currency"
 
       scope = Currency.latest(date)
       scope = scope.only(*(symbols + [base])) if symbols
diff --git a/lib/quote/interval.rb b/lib/quote/interval.rb
index 6061924..2559b49 100644
--- a/lib/quote/interval.rb
+++ b/lib/quote/interval.rb
@@ -1,15 +1,17 @@
 # frozen_string_literal: true
 
-require 'quote/base'
+require "quote/base"
 
 module Quote
   class Interval < Base
     def formatted
-      { amount:,
+      {
+        amount:,
         base:,
         start_date: result.keys.first,
         end_date: result.keys.last,
-        rates: result }
+        rates: result,
+      }
     end
 
     def cache_key
@@ -21,7 +23,7 @@ module Quote
     private
 
     def fetch_data
-      require 'currency'
+      require "currency"
 
       scope = Currency.between(date)
       scope = scope.only(*(symbols + [base])) if symbols
diff --git a/lib/roundable.rb b/lib/roundable.rb
index 11265f8..b4a1c96 100644
--- a/lib/roundable.rb
+++ b/lib/roundable.rb
@@ -13,18 +13,18 @@ module Roundable
     if value > 5000
       value.round
     elsif value > 80
-      Float(format('%<value>.2f', value:))
+      Float(format("%<value>.2f", value:))
     elsif value > 20
-      Float(format('%<value>.3f', value:))
+      Float(format("%<value>.3f", value:))
     elsif value > 1
-      Float(format('%<value>.4f', value:))
+      Float(format("%<value>.4f", value:))
     # I had originally opted to round smaller numbers simply to five decimal
     # places but introduced this refinement to handle an edge case where a
     # lower-rate base currency like IDR produces less precise quotes.
     elsif value > 0.0001
-      Float(format('%<value>.5f', value:))
+      Float(format("%<value>.5f", value:))
     else
-      Float(format('%<value>.6f', value:))
+      Float(format("%<value>.6f", value:))
     end
   end
 end
diff --git a/lib/scheduler/daemon.rb b/lib/scheduler/daemon.rb
index fc1d8d4..bf6a323 100644
--- a/lib/scheduler/daemon.rb
+++ b/lib/scheduler/daemon.rb
@@ -4,8 +4,10 @@ module Scheduler
   class Daemon
     attr_reader :pid
 
-    def self.start
-      new.start
+    class << self
+      def start
+        new.start
+      end
     end
 
     def initialize
@@ -25,7 +27,7 @@ module Scheduler
     private
 
     def run
-      load 'bin/schedule'
+      load("bin/schedule")
     end
 
     def monitor_child
@@ -33,7 +35,7 @@ module Scheduler
 
       @child_monitor = Thread.new do
         loop do
-          sleep 5
+          sleep(5)
           unless alive?(pid)
             @pid = nil
             start
@@ -46,7 +48,7 @@ module Scheduler
       Thread.new do
         loop do
           exit unless alive?(@parent_pid)
-          sleep 1
+          sleep(1)
         end
       end
     end
diff --git a/lib/tasks/db.rake b/lib/tasks/db.rake
index ff2028b..2f70861 100644
--- a/lib/tasks/db.rake
+++ b/lib/tasks/db.rake
@@ -1,26 +1,26 @@
 # frozen_string_literal: true
 
 namespace :db do
-  desc 'Run database migrations'
+  desc "Run database migrations"
   task migrate: :environment do
     Sequel.extension(:migration)
     db = Sequel::DATABASES.first
-    dir = App.root.join('db/migrate')
+    dir = App.root.join("db/migrate")
     opts = {}
-    opts.update(target: ENV['VERSION'].to_i) if ENV['VERSION']
+    opts.update(target: ENV["VERSION"].to_i) if ENV["VERSION"]
 
     Sequel::IntegerMigrator.new(db, dir, opts).run
   end
 
-  desc 'Run database migrations and seed data'
-  task prepare: %w[db:migrate rates:all]
+  desc "Run database migrations and seed data"
+  task prepare: ["db:migrate", "rates:all"]
 
   namespace :test do
-    desc 'Run database migrations and seed with saved data'
+    desc "Run database migrations and seed with saved data"
     task :prepare do
-      ENV['APP_ENV'] ||= 'test'
-      Rake::Task['db:migrate'].invoke
-      Rake::Task['rates:seed_with_saved_data'].invoke
+      ENV["APP_ENV"] ||= "test"
+      Rake::Task["db:migrate"].invoke
+      Rake::Task["rates:seed_with_saved_data"].invoke
     end
   end
 end
diff --git a/lib/tasks/environment.rake b/lib/tasks/environment.rake
index ac9e199..c54f079 100644
--- a/lib/tasks/environment.rake
+++ b/lib/tasks/environment.rake
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-desc 'Load environment'
+desc "Load environment"
 task :environment do
-  require './config/environment'
+  require "./config/environment"
 end
diff --git a/lib/tasks/rates.rake b/lib/tasks/rates.rake
index 91f4541..94667cb 100644
--- a/lib/tasks/rates.rake
+++ b/lib/tasks/rates.rake
@@ -1,27 +1,27 @@
 # frozen_string_literal: true
 
 namespace :rates do
-  desc 'Load all'
+  desc "Load all"
   task all: :environment do
-    require 'bank'
+    require "bank"
     Bank.fetch_all!
   end
 
-  desc 'Load last 90 days'
+  desc "Load last 90 days"
   task ninety_days: :environment do
-    require 'bank'
+    require "bank"
     Bank.fetch_ninety_days!
   end
 
-  desc 'Load current'
+  desc "Load current"
   task current: :environment do
-    require 'bank'
+    require "bank"
     Bank.fetch_current!
   end
 
-  desc 'Seed with saved data'
+  desc "Seed with saved data"
   task :seed_with_saved_data do
-    require 'bank'
+    require "bank"
     Bank.seed_with_saved_data!
   end
 end
diff --git a/lib/tasks/sitemap.rake b/lib/tasks/sitemap.rake
index 863cca0..b382b54 100644
--- a/lib/tasks/sitemap.rake
+++ b/lib/tasks/sitemap.rake
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 begin
-  require 'sitemap_generator/tasks'
+  require "sitemap_generator/tasks"
 rescue LoadError
   return
 end
diff --git a/lib/tasks/test.rake b/lib/tasks/test.rake
index 71dbd60..fa9c9a3 100644
--- a/lib/tasks/test.rake
+++ b/lib/tasks/test.rake
@@ -1,18 +1,18 @@
 # frozen_string_literal: true
 
-require 'rake/testtask'
+require "rake/testtask"
 begin
-  require 'rubocop/rake_task'
+  require "rubocop/rake_task"
 rescue LoadError
   return
 end
 
 Rake::TestTask.new(test: :environment) do |t|
-  t.libs.push('lib')
-  t.test_files = FileList['spec/**/*_spec.rb']
-  t.ruby_opts += ['-W0']
+  t.libs.push("lib")
+  t.test_files = FileList["spec/**/*_spec.rb"]
+  t.ruby_opts += ["-W0"]
 end
 
 RuboCop::RakeTask.new
 
-task default: %w[rubocop db:test:prepare test]
+task default: ["rubocop", "db:test:prepare", "test"]
diff --git a/lib/web/server.rb b/lib/web/server.rb
index f3a5857..ce41bc5 100644
--- a/lib/web/server.rb
+++ b/lib/web/server.rb
@@ -1,20 +1,20 @@
 # frozen_string_literal: true
 
-require 'oj'
-require 'rack/contrib/jsonp'
-require 'rack/cors'
-require 'roda'
+require "oj"
+require "rack/contrib/jsonp"
+require "rack/cors"
+require "roda"
 
-require 'currency_names'
-require 'query'
-require 'quote'
+require "currency_names"
+require "query"
+require "quote"
 
 module Web
   class Server < Roda
     use Rack::Cors do
       allow do
-        origins '*'
-        resource '*', headers: :any, methods: %i[get options]
+        origins "*"
+        resource "*", headers: :any, methods: [:get, :options]
       end
     end
     use Rack::JSONP
@@ -23,51 +23,52 @@ module Web
 
     plugin :halt
     plugin :error_handler do |error|
-      request.halt 422, { message: error.message }
+      request.halt(422, { message: error.message })
     end
 
     plugin :indifferent_params
 
-    plugin :json, content_type: 'application/json; charset=utf-8',
-                  serializer: ->(o) { Oj.dump(o, mode: :compat) }
+    plugin :json,
+      content_type: "application/json; charset=utf-8",
+      serializer: ->(o) { Oj.dump(o, mode: :compat) }
 
     plugin :params_capturing
 
     route do |r|
-      response.cache_control public: true, max_age: 900
+      response.cache_control(public: true, max_age: 900)
 
       r.root do
-        { docs: 'https://www.frankfurter.app/docs' }
+        { docs: "https://www.frankfurter.app/docs" }
       end
 
       r.is(/latest|current/) do
-        r.params['date'] = Date.today.to_s
+        r.params["date"] = Date.today.to_s
         quote = quote_end_of_day(r)
-        r.etag quote.cache_key
+        r.etag(quote.cache_key)
 
         quote.formatted
       end
 
       r.is(/(\d{4}-\d{2}-\d{2})/) do
-        r.params['date'] = r.params['captures'].first
+        r.params["date"] = r.params["captures"].first
         quote = quote_end_of_day(r)
-        r.etag quote.cache_key
+        r.etag(quote.cache_key)
 
         quote.formatted
       end
 
       r.is(/(\d{4}-\d{2}-\d{2})\.\.(\d{4}-\d{2}-\d{2})?/) do
-        r.params['start_date'] = r.params['captures'].first
-        r.params['end_date'] = r.params['captures'][1] || Date.today.to_s
+        r.params["start_date"] = r.params["captures"].first
+        r.params["end_date"] = r.params["captures"][1] || Date.today.to_s
         quote = quote_interval(r)
-        r.etag quote.cache_key
+        r.etag(quote.cache_key)
 
         quote.formatted
       end
 
-      r.is 'currencies' do
+      r.is("currencies") do
         currency_names = CurrencyNames.new
-        r.etag currency_names.cache_key
+        r.etag(currency_names.cache_key)
 
         currency_names.formatted
       end
@@ -79,7 +80,7 @@ module Web
       query = Query.build(request.params)
       quote = Quote::EndOfDay.new(**query)
       quote.perform
-      request.halt 404, { message: 'not found' } if quote.not_found?
+      request.halt(404, { message: "not found" }) if quote.not_found?
 
       quote
     end
@@ -88,7 +89,7 @@ module Web
       query = Query.build(request.params)
       quote = Quote::Interval.new(**query)
       quote.perform
-      request.halt 404, { message: 'not found' } if quote.not_found?
+      request.halt(404, { message: "not found" }) if quote.not_found?
 
       quote
     end
diff --git a/spec/bank/feed_spec.rb b/spec/bank/feed_spec.rb
index e52a6fe..5c14e83 100644
--- a/spec/bank/feed_spec.rb
+++ b/spec/bank/feed_spec.rb
@@ -1,46 +1,46 @@
 # frozen_string_literal: true
 
-require_relative '../helper'
-require 'bank/feed'
+require_relative "../helper"
+require "bank/feed"
 
 module Bank
   describe Feed do
     before do
-      VCR.insert_cassette 'feed'
+      VCR.insert_cassette("feed")
     end
 
     after do
       VCR.eject_cassette
     end
 
-    it 'fetches current rates' do
+    it "fetches current rates" do
       feed = Feed.current
-      _(feed.count).must_be :==, 1
+      _(feed.count).must_be(:==, 1)
     end
 
-    it 'fetches rates for the past 90 days' do
+    it "fetches rates for the past 90 days" do
       feed = Feed.ninety_days
-      _(feed.count).must_be :>, 1
-      _(feed.count).must_be :<=, 90
+      _(feed.count).must_be(:>, 1)
+      _(feed.count).must_be(:<=, 90)
     end
 
-    it 'fetches historical rates' do
+    it "fetches historical rates" do
       feed = Feed.historical
-      _(feed.count).must_be :>, 90
+      _(feed.count).must_be(:>, 90)
     end
 
-    it 'parses dates' do
+    it "parses dates" do
       feed = Feed.current
       day = feed.first
-      _(day[:date]).must_be_kind_of Date
+      _(day[:date]).must_be_kind_of(Date)
     end
 
-    it 'parses rates' do
+    it "parses rates" do
       feed = Feed.current
       day = feed.first
       day[:rates].each do |iso_code, value|
-        _(iso_code).must_be_kind_of String
-        _(value).must_be_kind_of Float
+        _(iso_code).must_be_kind_of(String)
+        _(value).must_be_kind_of(Float)
       end
     end
   end
diff --git a/spec/bank_spec.rb b/spec/bank_spec.rb
index 83aac54..0e1e8e5 100644
--- a/spec/bank_spec.rb
+++ b/spec/bank_spec.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-require_relative 'helper'
-require 'bank'
+require_relative "helper"
+require "bank"
 
 describe Bank do
   around do |test|
@@ -13,55 +13,55 @@ describe Bank do
   end
 
   before do
-    VCR.insert_cassette 'feed'
+    VCR.insert_cassette("feed")
   end
 
   after do
     VCR.eject_cassette
   end
 
-  it 'fetches all rates' do
+  it "fetches all rates" do
     Bank.fetch_all!
-    _(Day.count).must_be :>, 90
+    _(Day.count).must_be(:>, 90)
   end
 
-  it 'does not duplicate when fetching all rates' do
+  it "does not duplicate when fetching all rates" do
     Bank.fetch_all!
     count = Day.count
     Bank.fetch_all!
-    _(Day.count).must_equal count
+    _(Day.count).must_equal(count)
   end
 
-  it 'fetches rates for last 90 days' do
+  it "fetches rates for last 90 days" do
     Bank.fetch_ninety_days!
-    _(Day.count).must_be :>, 1
-    _(Day.count).must_be :<, 90
+    _(Day.count).must_be(:>, 1)
+    _(Day.count).must_be(:<, 90)
   end
 
-  it 'seeds rates with saved data' do
+  it "seeds rates with saved data" do
     Bank.seed_with_saved_data!
-    _(Day.count).must_be :>, 90
+    _(Day.count).must_be(:>, 90)
   end
 
-  it 'does not duplicate when fetching rates for last 90 days' do
+  it "does not duplicate when fetching rates for last 90 days" do
     Bank.fetch_ninety_days!
     count = Day.count
     Bank.fetch_ninety_days!
-    _(Day.count).must_equal count
+    _(Day.count).must_equal(count)
   end
 
-  it 'fetches current rates' do
+  it "fetches current rates" do
     Bank.fetch_current!
-    _(Day.count).must_equal 1
+    _(Day.count).must_equal(1)
   end
 
-  it 'does not duplicate when fetching current rates' do
+  it "does not duplicate when fetching current rates" do
     2.times { Bank.fetch_current! }
-    _(Day.count).must_equal 1
+    _(Day.count).must_equal(1)
   end
 
-  it 'replaces all rates' do
+  it "replaces all rates" do
     Bank.replace_all!
-    _(Day.count).must_be :>, 90
+    _(Day.count).must_be(:>, 90)
   end
 end
diff --git a/spec/currency_names_spec.rb b/spec/currency_names_spec.rb
index 096d846..22ffd25 100644
--- a/spec/currency_names_spec.rb
+++ b/spec/currency_names_spec.rb
@@ -1,18 +1,18 @@
 # frozen_string_literal: true
 
-require_relative 'helper'
-require 'currency_names'
+require_relative "helper"
+require "currency_names"
 
 describe CurrencyNames do
   let(:currency_names) do
     CurrencyNames.new
   end
 
-  it 'returns currency codes and names' do
-    _(currency_names.formatted['USD']).must_equal 'United States Dollar'
+  it "returns currency codes and names" do
+    _(currency_names.formatted["USD"]).must_equal("United States Dollar")
   end
 
-  it 'has a cache key' do
-    _(currency_names.cache_key).wont_be :empty?
+  it "has a cache key" do
+    _(currency_names.cache_key).wont_be(:empty?)
   end
 end
diff --git a/spec/currency_spec.rb b/spec/currency_spec.rb
index 9b91190..b627640 100644
--- a/spec/currency_spec.rb
+++ b/spec/currency_spec.rb
@@ -1,48 +1,48 @@
 # frozen_string_literal: true
 
-require_relative 'helper'
-require 'currency'
-require 'minitest/autorun'
+require_relative "helper"
+require "currency"
+require "minitest/autorun"
 
 describe Currency do
-  describe '.latest' do
-    it 'returns latest rates' do
+  describe ".latest" do
+    it "returns latest rates" do
       data = Currency.latest.all
-      _(data.count).must_be :>, 1
+      _(data.count).must_be(:>, 1)
     end
   end
 
-  describe '.between' do
+  describe ".between" do
     let(:day) do
-      Date.parse('2010-01-01')
+      Date.parse("2010-01-01")
     end
 
-    it 'returns everything up to a year' do
+    it "returns everything up to a year" do
       interval = day..day + 365
-      _(Currency.between(interval).map(:date).uniq.count).must_be :>, 52
+      _(Currency.between(interval).map(:date).uniq.count).must_be(:>, 52)
     end
 
-    it 'samples weekly over a year' do
+    it "samples weekly over a year" do
       interval = day..day + 366
-      _(Currency.between(interval).map(:date).uniq.count).must_be :<, 54
+      _(Currency.between(interval).map(:date).uniq.count).must_be(:<, 54)
     end
 
-    it 'sorts by date when sampling' do
+    it "sorts by date when sampling" do
       interval = day..day + 366
       dates = Currency.between(interval).map(:date)
-      _(dates).must_equal dates.sort
+      _(dates).must_equal(dates.sort)
     end
   end
 
-  describe '.only' do
-    it 'filters symbols' do
-      iso_codes = %w[CAD USD]
+  describe ".only" do
+    it "filters symbols" do
+      iso_codes = ["CAD", "USD"]
       data = Currency.latest.only(*iso_codes).all
-      _(data.map(&:iso_code).sort).must_equal iso_codes
+      _(data.map(&:iso_code).sort).must_equal(iso_codes)
     end
 
-    it 'returns nothing if no matches' do
-      _(Currency.only('FOO').all).must_be_empty
+    it "returns nothing if no matches" do
+      _(Currency.only("FOO").all).must_be_empty
     end
   end
 end
diff --git a/spec/day_spec.rb b/spec/day_spec.rb
index eedac74..0d28a4c 100644
--- a/spec/day_spec.rb
+++ b/spec/day_spec.rb
@@ -1,32 +1,32 @@
 # frozen_string_literal: true
 
-require_relative 'helper'
-require 'day'
+require_relative "helper"
+require "day"
 
 describe Day do
-  describe '.latest' do
-    it 'returns latest rates before given date' do
-      date = Date.parse('2010-01-01')
+  describe ".latest" do
+    it "returns latest rates before given date" do
+      date = Date.parse("2010-01-01")
       data = Day.latest(date)
-      _(data.first.date).must_be :<=, date
+      _(data.first.date).must_be(:<=, date)
     end
 
-    it 'returns nothing if there are no rates before given date' do
-      _(Day.latest(Date.parse('1998-01-01'))).must_be_empty
+    it "returns nothing if there are no rates before given date" do
+      _(Day.latest(Date.parse("1998-01-01"))).must_be_empty
     end
   end
 
-  describe '.between' do
-    it 'returns rates between given dates' do
-      start_date = Date.parse('2010-01-01')
-      end_date = Date.parse('2010-01-31')
+  describe ".between" do
+    it "returns rates between given dates" do
+      start_date = Date.parse("2010-01-01")
+      end_date = Date.parse("2010-01-31")
       dates = Day.between((start_date..end_date)).map(:date).sort
-      _(dates.first).must_be :>=, start_date
-      _(dates.last).must_be :<=, end_date
+      _(dates.first).must_be(:>=, start_date)
+      _(dates.last).must_be(:<=, end_date)
     end
 
-    it 'returns nothing if there are no rates between given dates' do
-      interval = (Date.parse('1998-01-01')..Date.parse('1998-01-31'))
+    it "returns nothing if there are no rates between given dates" do
+      interval = (Date.parse("1998-01-01")..Date.parse("1998-01-31"))
       _(Day.between(interval)).must_be_empty
     end
   end
diff --git a/spec/edge_cases_spec.rb b/spec/edge_cases_spec.rb
index 9381489..cf5bff7 100644
--- a/spec/edge_cases_spec.rb
+++ b/spec/edge_cases_spec.rb
@@ -1,10 +1,10 @@
 # frozen_string_literal: true
 
-require_relative 'helper'
-require 'rack/test'
-require 'web/server'
+require_relative "helper"
+require "rack/test"
+require "web/server"
 
-describe 'the server' do
+describe "the server" do
   include Rack::Test::Methods
 
   let(:app) { Web::Server.freeze }
@@ -13,38 +13,38 @@ describe 'the server' do
     Oj.load(last_response.body)
   end
 
-  it 'handles unfound pages' do
-    get '/foo'
-    _(last_response.status).must_equal 404
+  it "handles unfound pages" do
+    get "/foo"
+    _(last_response.status).must_equal(404)
   end
 
-  it 'will not process an invalid date' do
-    get '/2010-31-01'
-    _(last_response).must_be :unprocessable?
+  it "will not process an invalid date" do
+    get "/2010-31-01"
+    _(last_response).must_be(:unprocessable?)
   end
 
-  it 'will not process a date before 2000' do
-    get '/1999-01-01'
-    _(last_response).must_be :not_found?
+  it "will not process a date before 2000" do
+    get "/1999-01-01"
+    _(last_response).must_be(:not_found?)
   end
 
-  it 'will not process an unavailable base' do
-    get '/latest?base=UAH'
-    _(last_response).must_be :not_found?
+  it "will not process an unavailable base" do
+    get "/latest?base=UAH"
+    _(last_response).must_be(:not_found?)
   end
 
-  it 'handles malformed queries' do
-    get '/latest?base=USD?callback=?'
-    _(last_response).must_be :not_found?
+  it "handles malformed queries" do
+    get "/latest?base=USD?callback=?"
+    _(last_response).must_be(:not_found?)
   end
 
-  it 'does not return stale dates' do
+  it "does not return stale dates" do
     Day.db.transaction do
-      get '/latest'
-      date = json['date']
+      get "/latest"
+      date = json["date"]
       Day.latest.delete
-      get '/latest'
-      _(json['date']).wont_equal date
+      get "/latest"
+      _(json["date"]).wont_equal(date)
       raise Sequel::Rollback
     end
   end
diff --git a/spec/helper.rb b/spec/helper.rb
index 3264453..89210af 100644
--- a/spec/helper.rb
+++ b/spec/helper.rb
@@ -1,24 +1,23 @@
 # frozen_string_literal: true
 
-ENV['APP_ENV'] ||= 'test'
+ENV["APP_ENV"] ||= "test"
 
 # Keep SimpleCov at top.
-require 'simplecov'
+require "simplecov"
 
 SimpleCov.start do
-  add_filter '/spec/'
+  add_filter "/spec/"
 end
 
-require_relative '../config/environment'
+require_relative "../config/environment"
 
-require 'minitest/autorun'
-require 'minitest/around/spec'
-require 'minitest/focus'
-require 'pry-byebug'
-require 'vcr'
-require 'webmock'
+require "minitest/autorun"
+require "minitest/around/spec"
+require "minitest/focus"
+require "vcr"
+require "webmock"
 
 VCR.configure do |c|
-  c.cassette_library_dir = 'spec/vcr_cassettes'
-  c.hook_into :webmock
+  c.cassette_library_dir = "spec/vcr_cassettes"
+  c.hook_into(:webmock)
 end
diff --git a/spec/query_spec.rb b/spec/query_spec.rb
index 45756b8..be3fa63 100644
--- a/spec/query_spec.rb
+++ b/spec/query_spec.rb
@@ -1,72 +1,72 @@
 # frozen_string_literal: true
 
-require_relative 'helper'
-require 'query'
+require_relative "helper"
+require "query"
 
 describe Query do
-  it 'builds a query hash' do
-    _(Query.build(date: '2014-01-01')).must_be_kind_of Hash
+  it "builds a query hash" do
+    _(Query.build(date: "2014-01-01")).must_be_kind_of(Hash)
   end
 
-  it 'returns given amount' do
-    query = Query.new(amount: '100')
-    _(query.amount).must_equal 100.0
+  it "returns given amount" do
+    query = Query.new(amount: "100")
+    _(query.amount).must_equal(100.0)
   end
 
-  it 'defaults amount to nothing' do
+  it "defaults amount to nothing" do
     query = Query.new
     _(query.amount).must_be_nil
   end
 
-  it 'returns given base' do
-    query = Query.new(base: 'USD')
-    _(query.base).must_equal 'USD'
+  it "returns given base" do
+    query = Query.new(base: "USD")
+    _(query.base).must_equal("USD")
   end
 
-  it 'upcases given base' do
-    query = Query.new(base: 'usd')
-    _(query.base).must_equal 'USD'
+  it "upcases given base" do
+    query = Query.new(base: "usd")
+    _(query.base).must_equal("USD")
   end
 
-  it 'defaults base to nothing' do
+  it "defaults base to nothing" do
     query = Query.new
     _(query.base).must_be_nil
   end
 
-  it 'aliases base with from' do
-    query = Query.new(from: 'USD')
-    _(query.base).must_equal 'USD'
+  it "aliases base with from" do
+    query = Query.new(from: "USD")
+    _(query.base).must_equal("USD")
   end
 
-  it 'returns given symbols' do
-    query = Query.new(symbols: 'USD,GBP')
-    _(query.symbols).must_equal %w[USD GBP]
+  it "returns given symbols" do
+    query = Query.new(symbols: "USD,GBP")
+    _(query.symbols).must_equal(["USD", "GBP"])
   end
 
-  it 'upcases given symbols' do
-    query = Query.new(symbols: 'usd,gbp')
-    _(query.symbols).must_equal %w[USD GBP]
+  it "upcases given symbols" do
+    query = Query.new(symbols: "usd,gbp")
+    _(query.symbols).must_equal(["USD", "GBP"])
   end
 
-  it 'aliases symbols with to' do
-    query = Query.new(to: 'USD')
-    _(query.symbols).must_equal ['USD']
+  it "aliases symbols with to" do
+    query = Query.new(to: "USD")
+    _(query.symbols).must_equal(["USD"])
   end
 
-  it 'defaults symbols to nothing' do
+  it "defaults symbols to nothing" do
     query = Query.new
     _(query.symbols).must_be_nil
   end
 
-  it 'returns given date' do
-    date = '2014-01-01'
+  it "returns given date" do
+    date = "2014-01-01"
     query = Query.new(date:)
-    _(query.date).must_equal Date.parse(date)
+    _(query.date).must_equal(Date.parse(date))
   end
 
-  it 'returns given date interval' do
-    start_date = '2014-01-01'
-    end_date = '2014-12-31'
+  it "returns given date interval" do
+    start_date = "2014-01-01"
+    end_date = "2014-12-31"
     query = Query.new(start_date:, end_date:)
     _(query.date).must_equal((Date.parse(start_date)..Date.parse(end_date)))
   end
diff --git a/spec/quote/base_spec.rb b/spec/quote/base_spec.rb
index b1bf2c0..eed7fbe 100644
--- a/spec/quote/base_spec.rb
+++ b/spec/quote/base_spec.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-require_relative '../helper'
-require 'quote/base'
+require_relative "../helper"
+require "quote/base"
 
 module Quote
   describe Base do
@@ -13,83 +13,83 @@ module Quote
       klass.new(date: Date.today)
     end
 
-    it 'requires data' do
-      _ { quote.perform }.must_raise NotImplementedError
+    it "requires data" do
+      _ { quote.perform }.must_raise(NotImplementedError)
     end
 
-    it 'does not know how to format result' do
-      _ { quote.formatted }.must_raise NotImplementedError
+    it "does not know how to format result" do
+      _ { quote.formatted }.must_raise(NotImplementedError)
     end
 
-    it 'does not know how to generate a cache key' do
-      _ { quote.cache_key }.must_raise NotImplementedError
+    it "does not know how to generate a cache key" do
+      _ { quote.cache_key }.must_raise(NotImplementedError)
     end
 
-    it 'defaults base to Euro' do
-      _(quote.base).must_equal 'EUR'
+    it "defaults base to Euro" do
+      _(quote.base).must_equal("EUR")
     end
 
-    it 'defaults amount to 1' do
-      _(quote.amount).must_equal 1
+    it "defaults amount to 1" do
+      _(quote.amount).must_equal(1)
     end
 
-    describe 'when given data' do
+    describe "when given data" do
       before do
         def quote.fetch_data
           []
         end
       end
 
-      it 'performs' do
+      it "performs" do
         assert quote.perform
       end
 
-      it 'performs only once' do
+      it "performs only once" do
         quote.perform
 
         refute quote.perform
       end
     end
 
-    describe 'when rebasing from an unavailable currency' do
+    describe "when rebasing from an unavailable currency" do
       let(:date) do
-        Date.parse('2000-01-01')
+        Date.parse("2000-01-01")
       end
 
       let(:quote) do
-        klass.new(date:, base: 'ILS')
+        klass.new(date:, base: "ILS")
       end
 
       before do
         def quote.fetch_data
-          [{ date:, iso_code: 'USD', rate: 1 }]
+          [{ date:, iso_code: "USD", rate: 1 }]
         end
       end
 
-      it 'finds nothing' do
+      it "finds nothing" do
         quote.perform
-        _(quote.not_found?).must_equal true
+        _(quote.not_found?).must_equal(true)
       end
     end
 
-    describe 'when rebasing and converting to an unavailable currency' do
+    describe "when rebasing and converting to an unavailable currency" do
       let(:date) do
         Date.today
       end
 
       let(:quote) do
-        klass.new(date:, base: 'USD', symbols: ['FOO'])
+        klass.new(date:, base: "USD", symbols: ["FOO"])
       end
 
       before do
         def quote.fetch_data
-          [{ date:, iso_code: 'USD', rate: 1 }]
+          [{ date:, iso_code: "USD", rate: 1 }]
         end
       end
 
-      it 'finds nothing' do
+      it "finds nothing" do
         quote.perform
-        _(quote.not_found?).must_equal true
+        _(quote.not_found?).must_equal(true)
       end
     end
   end
diff --git a/spec/quote/end_of_day_spec.rb b/spec/quote/end_of_day_spec.rb
index ae78675..469abbe 100644
--- a/spec/quote/end_of_day_spec.rb
+++ b/spec/quote/end_of_day_spec.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require_relative '../helper'
-require 'quote/end_of_day'
+require_relative "../helper"
+require "quote/end_of_day"
 
 module Quote
   describe EndOfDay do
     let(:date) do
-      Date.parse('2010-10-10')
+      Date.parse("2010-10-10")
     end
 
     let(:quote) do
@@ -17,66 +17,66 @@ module Quote
       quote.perform
     end
 
-    it 'returns rates' do
-      _(quote.formatted[:rates]).wont_be :empty?
+    it "returns rates" do
+      _(quote.formatted[:rates]).wont_be(:empty?)
     end
 
-    it 'quotes given date' do
-      _(Date.parse(quote.formatted[:date])).must_be :<=, date
+    it "quotes given date" do
+      _(Date.parse(quote.formatted[:date])).must_be(:<=, date)
     end
 
-    it 'quotes against the Euro' do
-      _(quote.formatted[:rates].keys).wont_include 'EUR'
+    it "quotes against the Euro" do
+      _(quote.formatted[:rates].keys).wont_include("EUR")
     end
 
-    it 'sorts rates' do
+    it "sorts rates" do
       rates = quote.formatted[:rates]
-      _(rates.keys).must_equal rates.keys.sort
+      _(rates.keys).must_equal(rates.keys.sort)
     end
 
-    it 'has a cache key' do
-      _(quote.cache_key).wont_be :empty?
+    it "has a cache key" do
+      _(quote.cache_key).wont_be(:empty?)
     end
 
-    describe 'given a new base' do
+    describe "given a new base" do
       let(:quote) do
-        EndOfDay.new(date:, base: 'USD')
+        EndOfDay.new(date:, base: "USD")
       end
 
-      it 'quotes against that base' do
-        _(quote.formatted[:rates].keys).wont_include 'USD'
+      it "quotes against that base" do
+        _(quote.formatted[:rates].keys).wont_include("USD")
       end
 
-      it 'sorts rates' do
+      it "sorts rates" do
         rates = quote.formatted[:rates]
-        _(rates.keys).must_equal rates.keys.sort
+        _(rates.keys).must_equal(rates.keys.sort)
       end
     end
 
-    describe 'given symbols' do
+    describe "given symbols" do
       let(:quote) do
-        EndOfDay.new(date:, symbols: %w[USD GBP JPY])
+        EndOfDay.new(date:, symbols: ["USD", "GBP", "JPY"])
       end
 
-      it 'quotes only for those symbols' do
+      it "quotes only for those symbols" do
         rates = quote.formatted[:rates]
-        _(rates.keys).must_include 'USD'
-        _(rates.keys).wont_include 'CAD'
+        _(rates.keys).must_include("USD")
+        _(rates.keys).wont_include("CAD")
       end
 
-      it 'sorts rates' do
+      it "sorts rates" do
         rates = quote.formatted[:rates]
-        _(rates.keys).must_equal rates.keys.sort
+        _(rates.keys).must_equal(rates.keys.sort)
       end
     end
 
-    describe 'when given an amount' do
+    describe "when given an amount" do
       let(:quote) do
         EndOfDay.new(date:, amount: 100)
       end
 
-      it 'calculates quotes for that amount' do
-        _(quote.formatted[:rates]['USD']).must_be :>, 10
+      it "calculates quotes for that amount" do
+        _(quote.formatted[:rates]["USD"]).must_be(:>, 10)
       end
     end
   end
diff --git a/spec/quote/interval_spec.rb b/spec/quote/interval_spec.rb
index 02b7caf..a590ccb 100644
--- a/spec/quote/interval_spec.rb
+++ b/spec/quote/interval_spec.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require_relative '../helper'
-require 'quote/interval'
+require_relative "../helper"
+require "quote/interval"
 
 module Quote
   describe Interval do
     let(:dates) do
-      (Date.parse('2010-01-01')..Date.parse('2010-12-31'))
+      (Date.parse("2010-01-01")..Date.parse("2010-12-31"))
     end
 
     let(:quote) do
@@ -17,76 +17,76 @@ module Quote
       quote.perform
     end
 
-    it 'returns rates' do
-      _(quote.formatted[:rates]).wont_be :empty?
+    it "returns rates" do
+      _(quote.formatted[:rates]).wont_be(:empty?)
     end
 
-    it 'quotes given date interval' do
-      _(Date.parse(quote.formatted[:start_date])).must_be :>=, dates.first
-      _(Date.parse(quote.formatted[:end_date])).must_be :<=, dates.last
+    it "quotes given date interval" do
+      _(Date.parse(quote.formatted[:start_date])).must_be(:>=, dates.first)
+      _(Date.parse(quote.formatted[:end_date])).must_be(:<=, dates.last)
     end
 
-    it 'quotes against the Euro' do
+    it "quotes against the Euro" do
       quote.formatted[:rates].each_value do |rates|
-        _(rates.keys).wont_include 'EUR'
+        _(rates.keys).wont_include("EUR")
       end
     end
 
-    it 'sorts rates' do
+    it "sorts rates" do
       quote.formatted[:rates].each_value do |rates|
-        _(rates.keys).must_equal rates.keys.sort
+        _(rates.keys).must_equal(rates.keys.sort)
       end
     end
 
-    it 'has a cache key' do
-      _(quote.cache_key).wont_be :empty?
+    it "has a cache key" do
+      _(quote.cache_key).wont_be(:empty?)
     end
 
-    describe 'given a new base' do
+    describe "given a new base" do
       let(:quote) do
-        Interval.new(date: dates, base: 'USD')
+        Interval.new(date: dates, base: "USD")
       end
 
-      it 'quotes against that base' do
+      it "quotes against that base" do
         quote.formatted[:rates].each_value do |rates|
-          _(rates.keys).wont_include 'USD'
+          _(rates.keys).wont_include("USD")
         end
       end
 
-      it 'sorts rates' do
+      it "sorts rates" do
         quote.formatted[:rates].each_value do |rates|
-          _(rates.keys).must_equal rates.keys.sort
+          _(rates.keys).must_equal(rates.keys.sort)
         end
       end
     end
 
-    describe 'given symbols' do
+    describe "given symbols" do
       let(:quote) do
-        Interval.new(date: dates, symbols: %w[USD GBP JPY])
+        Interval.new(date: dates, symbols: ["USD", "GBP", "JPY"])
       end
 
-      it 'quotes only for those symbols' do
+      it "quotes only for those symbols" do
         quote.formatted[:rates].each_value do |rates|
-          _(rates.keys).must_include 'USD'
-          _(rates.keys).wont_include 'CAD'
+          _(rates.keys).must_include("USD")
+          _(rates.keys).wont_include("CAD")
         end
       end
 
-      it 'sorts rates' do
+      it "sorts rates" do
         quote.formatted[:rates].each_value do |rates|
-          _(rates.keys).must_equal rates.keys.sort
+          _(rates.keys).must_equal(rates.keys.sort)
         end
       end
     end
 
-    describe 'when given an amount' do
+    describe "when given an amount" do
       let(:quote) do
         Interval.new(date: dates, amount: 100)
       end
 
-      it 'calculates quotes for that amount' do
+      it "calculates quotes for that amount" do
         quote.formatted[:rates].each_value do |rates|
-          _(rates['USD']).must_be :>, 10
+          _(rates["USD"]).must_be(:>, 10)
         end
       end
     end
diff --git a/spec/roundable_spec.rb b/spec/roundable_spec.rb
index 8e89fbd..71409d3 100644
--- a/spec/roundable_spec.rb
+++ b/spec/roundable_spec.rb
@@ -1,44 +1,44 @@
 # frozen_string_literal: true
 
-require_relative 'helper'
-require 'roundable'
+require_relative "helper"
+require "roundable"
 
 describe Roundable do
   include Roundable
 
-  it 'rounds values over 5,000 to zero decimal places' do
-    _(round(5000.123456)).must_equal 5000
+  it "rounds values over 5,000 to zero decimal places" do
+    _(round(5000.123456)).must_equal(5000)
   end
 
-  it 'rounds values over 80 and below 5,000 to two decimal places' do
-    _(round(80.123456)).must_equal 80.12
-    _(round(4999.123456)).must_equal 4999.12
+  it "rounds values over 80 and below 5,000 to two decimal places" do
+    _(round(80.123456)).must_equal(80.12)
+    _(round(4999.123456)).must_equal(4999.12)
   end
 
-  it 'rounds values over 20 and below 80 to three decimal places' do
-    _(round(79.123456)).must_equal 79.123
-    _(round(20.123456)).must_equal 20.123
+  it "rounds values over 20 and below 80 to three decimal places" do
+    _(round(79.123456)).must_equal(79.123)
+    _(round(20.123456)).must_equal(20.123)
   end
 
-  it 'rounds values over 1 and below 20 to four decimal places' do
-    _(round(19.123456)).must_equal 19.1235
-    _(round(1.123456)).must_equal 1.1235
+  it "rounds values over 1 and below 20 to four decimal places" do
+    _(round(19.123456)).must_equal(19.1235)
+    _(round(1.123456)).must_equal(1.1235)
   end
 
-  it 'rounds values below 1 to five decimal places' do
-    _(round(0.123456)).must_equal 0.12346
+  it "rounds values below 1 to five decimal places" do
+    _(round(0.123456)).must_equal(0.12346)
   end
 
-  it 'rounds values below 0.0001 to six decimal places' do
-    _(round(0.0000655)).must_equal 0.000066
+  it "rounds values below 0.0001 to six decimal places" do
+    _(round(0.0000655)).must_equal(0.000066)
   end
 
-  it 'conforms to ECB conventions' do
+  it "conforms to ECB conventions" do
     skip "We don't conform ¯_(ツ)_/¯"
-    require 'day'
+    require "day"
     rates = Day.all.sample.rates.to_a
     rates.shuffle.each_value do |rate|
-      _(round(rate)).must_equal rate
+      _(round(rate)).must_equal(rate)
     end
   end
 end
diff --git a/spec/web/server_spec.rb b/spec/web/server_spec.rb
index 228dbf4..bb81f0d 100644
--- a/spec/web/server_spec.rb
+++ b/spec/web/server_spec.rb
@@ -1,119 +1,119 @@
 # frozen_string_literal: true
 
-require_relative '../helper'
-require 'rack/test'
-require 'web/server'
+require_relative "../helper"
+require "rack/test"
+require "web/server"
 
-describe 'the server' do
+describe "the server" do
   include Rack::Test::Methods
 
   let(:app) { Web::Server.freeze }
   let(:json) { Oj.load(last_response.body) }
   let(:headers) { last_response.headers }
 
-  it 'returns link to docs' do
-    get '/'
-    _(json['docs']).wont_be_nil
+  it "returns link to docs" do
+    get "/"
+    _(json["docs"]).wont_be_nil
   end
 
-  it 'returns latest quotes' do
-    get '/latest'
-    _(last_response).must_be :ok?
+  it "returns latest quotes" do
+    get "/latest"
+    _(last_response).must_be(:ok?)
   end
 
-  it 'sets base currency' do
-    get '/latest'
+  it "sets base currency" do
+    get "/latest"
     res = Oj.load(last_response.body)
-    get '/latest?from=USD'
-    _(json).wont_equal res
+    get "/latest?from=USD"
+    _(json).wont_equal(res)
   end
 
-  it 'sets base amount' do
-    get '/latest?amount=10'
-    _(json['rates']['USD']).must_be :>, 10
+  it "sets base amount" do
+    get "/latest?amount=10"
+    _(json["rates"]["USD"]).must_be(:>, 10)
   end
 
-  it 'filters symbols' do
-    get '/latest?to=USD'
-    _(json['rates'].keys).must_equal %w[USD]
+  it "filters symbols" do
+    get "/latest?to=USD"
+    _(json["rates"].keys).must_equal(["USD"])
   end
 
-  it 'returns historical quotes' do
-    get '/2012-11-20'
-    _(json['rates']).wont_be :empty?
-    _(json['date']).must_equal '2012-11-20'
+  it "returns historical quotes" do
+    get "/2012-11-20"
+    _(json["rates"]).wont_be(:empty?)
+    _(json["date"]).must_equal("2012-11-20")
   end
 
-  it 'works around holidays' do
-    get '/2010-01-01'
-    _(json['rates']).wont_be :empty?
+  it "works around holidays" do
+    get "/2010-01-01"
+    _(json["rates"]).wont_be(:empty?)
   end
 
-  it 'returns an ETag' do
-    %w[/latest /2012-11-20].each do |path|
+  it "returns an ETag" do
+    ["/latest", "/2012-11-20"].each do |path|
       get path
-      _(headers['ETag']).wont_be_nil
+      _(headers["ETag"]).wont_be_nil
     end
   end
 
-  it 'returns a cache control header' do
-    %w[/latest /2012-11-20].each do |path|
+  it "returns a cache control header" do
+    ["/latest", "/2012-11-20"].each do |path|
       get path
-      _(headers['Cache-Control']).wont_be_nil
+      _(headers["Cache-Control"]).wont_be_nil
     end
   end
 
-  it 'allows cross-origin requests' do
-    %w[/ /latest /2012-11-20].each do |path|
-      header 'Origin', '*'
+  it "allows cross-origin requests" do
+    ["/", "/latest", "/2012-11-20"].each do |path|
+      header "Origin", "*"
       get path
 
-      assert headers.key?('Access-Control-Allow-Methods')
+      assert headers.key?("Access-Control-Allow-Methods")
     end
   end
 
-  it 'responds to preflight requests' do
-    %w[/ /latest /2012-11-20].each do |path|
-      header 'Origin', '*'
-      header 'Access-Control-Request-Method', 'GET'
-      header 'Access-Control-Request-Headers', 'Content-Type'
+  it "responds to preflight requests" do
+    ["/", "/latest", "/2012-11-20"].each do |path|
+      header "Origin", "*"
+      header "Access-Control-Request-Method", "GET"
+      header "Access-Control-Request-Headers", "Content-Type"
       options path
 
-      assert headers.key?('Access-Control-Allow-Methods')
+      assert headers.key?("Access-Control-Allow-Methods")
     end
   end
 
-  it 'converts an amount' do
-    get '/latest?from=GBP&to=USD&amount=100'
-    _(json['rates']['USD']).must_be :>, 100
+  it "converts an amount" do
+    get "/latest?from=GBP&to=USD&amount=100"
+    _(json["rates"]["USD"]).must_be(:>, 100)
   end
 
-  it 'returns rates for a given period' do
-    get '/2010-01-01..2010-12-31'
-    _(json['start_date']).wont_be :empty?
-    _(json['end_date']).wont_be :empty?
-    _(json['rates']).wont_be :empty?
+  it "returns rates for a given period" do
+    get "/2010-01-01..2010-12-31"
+    _(json["start_date"]).wont_be(:empty?)
+    _(json["end_date"]).wont_be(:empty?)
+    _(json["rates"]).wont_be(:empty?)
   end
 
-  it 'returns rates when given period does not include end date' do
-    get '/2010-01-01..'
-    _(json['start_date']).wont_be :empty?
-    _(json['end_date']).wont_be :empty?
-    _(json['rates']).wont_be :empty?
+  it "returns rates when given period does not include end date" do
+    get "/2010-01-01.."
+    _(json["start_date"]).wont_be(:empty?)
+    _(json["end_date"]).wont_be(:empty?)
+    _(json["rates"]).wont_be(:empty?)
   end
 
-  it 'returns currencies' do
-    get '/currencies'
-    _(json['USD']).must_equal 'United States Dollar'
+  it "returns currencies" do
+    get "/currencies"
+    _(json["USD"]).must_equal("United States Dollar")
   end
 
-  it 'handles JSONP' do
-    get '/latest?callback=foo'
-    _(last_response.body).must_be :start_with?, '/**/foo'
+  it "handles JSONP" do
+    get "/latest?callback=foo"
+    _(last_response.body).must_be(:start_with?, "/**/foo")
   end
 
-  it 'sets charset to utf-8' do
-    get '/currencies'
-    _(last_response.headers['content-type']).must_be :end_with?, 'charset=utf-8'
+  it "sets charset to utf-8" do
+    get "/currencies"
+    _(last_response.headers["content-type"]).must_be(:end_with?, "charset=utf-8")
   end
 end