diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..98e6ef6
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.db
diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 0000000..25f9952
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1,35 @@
+AllCops:
+  TargetRubyVersion: 3.4.1
+
+Layout/SpaceInsideArrayLiteralBrackets:
+  Enabled: false
+
+Style/StringLiterals:
+  Enabled: false
+
+Style/TrailingCommaInHashLiteral:
+  Enabled: false
+
+Style/TrailingCommaInArrayLiteral:
+  Enabled: false
+
+Style/FrozenStringLiteralComment:
+  Enabled: false
+
+Layout/SpaceAroundOperators:
+  Enabled: false
+
+Metrics/AbcSize:
+  Enabled: false
+
+Metrics/MethodLength:
+  Enabled: false
+
+Layout/EmptyLineAfterGuardClause:
+  Enabled: false
+
+Metrics/PerceivedComplexity:
+  Enabled: false
+
+Metrics/CyclomaticComplexity:
+  Enabled: false
diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 0000000..47b322c
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+3.4.1
diff --git a/.solargraph.yml b/.solargraph.yml
new file mode 100644
index 0000000..5ff109f
--- /dev/null
+++ b/.solargraph.yml
@@ -0,0 +1,25 @@
+---
+include:
+- "**/*.rb"
+exclude:
+- spec/**/*
+- test/**/*
+- vendor/**/*
+- ".bundle/**/*"
+require: []
+domains: []
+reporters:
+- rubocop
+formatter:
+  rubocop:
+    cops: safe
+    except: []
+    only: []
+    extra_args: []
+require_paths: []
+plugins: []
+max_files: 5000
+useBundler: true
+rubyVersion: "3.4.1"
+workspace:
+  root: .
diff --git a/Gemfile b/Gemfile
new file mode 100644
index 0000000..3397785
--- /dev/null
+++ b/Gemfile
@@ -0,0 +1,9 @@
+source "https://rubygems.org"
+
+gem "sinatra"
+
+gem "xxhash"
+
+gem "sequel"
+
+gem "json"
diff --git a/Gemfile.lock b/Gemfile.lock
new file mode 100644
index 0000000..b4f6a62
--- /dev/null
+++ b/Gemfile.lock
@@ -0,0 +1,40 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    base64 (0.3.0)
+    bigdecimal (3.2.2)
+    logger (1.7.0)
+    mustermann (3.0.3)
+      ruby2_keywords (~> 0.0.1)
+    rack (3.1.16)
+    rack-protection (4.1.1)
+      base64 (>= 0.1.0)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.1.1)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0)
+    ruby2_keywords (0.0.5)
+    sequel (5.93.0)
+      bigdecimal
+    sinatra (4.1.1)
+      logger (>= 1.6.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.1.1)
+      rack-session (>= 2.0.0, < 3)
+      tilt (~> 2.0)
+    tilt (2.6.0)
+    xxhash (0.6.0)
+
+PLATFORMS
+  ruby
+  x86_64-linux
+
+DEPENDENCIES
+  sequel
+  sinatra
+  xxhash
+
+BUNDLED WITH
+   2.6.9
diff --git a/API.md b/JS_API.md
similarity index 100%
rename from API.md
rename to JS_API.md
diff --git a/config/puma.rb b/config/puma.rb
new file mode 100644
index 0000000..72e639b
--- /dev/null
+++ b/config/puma.rb
@@ -0,0 +1 @@
+stdout_redirect "./log/puma.stdout.log", "./log/puma.stderr.log", true
diff --git a/db.json b/db.json
new file mode 100644
index 0000000..6919142
--- /dev/null
+++ b/db.json
@@ -0,0 +1,3 @@
+{
+  "account_num": 6
+}
\ No newline at end of file
diff --git a/db.rb b/db.rb
new file mode 100644
index 0000000..109e1be
--- /dev/null
+++ b/db.rb
@@ -0,0 +1,78 @@
+require "xxhash"
+require "sequel"
+require "json"
+
+ALPHANUM = [*"0".."9", *"A".."Z", *"a".."z", "-", "_"].freeze
+
+# DataBase handler module
+module DataBase
+  db_file = File.expand_path("infinsweeper.db")
+  DB = Sequel.connect("sqlite:///#{db_file}", single_threaded: false)
+
+  def self.player_list
+    DB["select * from Players"].all
+  end
+
+  def self.rm_player(email)
+    DB["delete from Players where email = ?", email].delete
+  end
+
+  def self.mk_player(username, email, pass)
+    raise ArgumentError, "Email format is wrong!" unless email.match?(/\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/)
+    raise ArgumentError, "Password must be at least 8 characters and valid format." unless
+      pass.match?(/\A[a-zA-Z0-9_.!?@#$%^&*()+=-]+\z/) && pass.length >= 8
+
+    digest = XXhash.xxh32(pass, 1234)
+
+    path = File.expand_path("db.json")
+    json = File.exist?(path) ? JSON.parse(File.read(path)) : {}
+    json["account_num"] ||= 0
+    account_num = json["account_num"]
+    json["account_num"] += 1
+    File.write(path, JSON.pretty_generate(json))
+    account_num = XXhash.xxh64(account_num, 1234)
+    code = ""
+    while account_num.positive?
+      code << ALPHANUM[account_num % 64]
+      account_num /= 64
+    end
+    code = code.reverse.rjust(12, "0")
+
+    DB["insert into Players (email, digest, username, code) values (?, ?, ?, ?)", email, digest, username, code].insert
+
+    send_email(email, username, code)
+    Thread.new do
+      sleep 24 * 60 * 60
+      rm_player(email) unless verified?(email)
+    end
+
+    "Successfully registered!"
+  rescue ArgumentError => e
+    e.message
+  rescue Sequel::UniqueConstraintViolation
+    "Account already exists with this email or username!"
+  end
+
+  def self.verify(code)
+    DB["update Players set code = ? where code = ?", "!", code].update != 0
+  end
+
+  def self.[](email)
+    DB["select * from Players where email = ?", email].first
+  end
+
+  def self.[]=(email, data)
+    DB["update Players set data = ? where email = ?", data, email].update
+  end
+
+  def self.authorized?(email, pass)
+    digest = XXhash.xxh32(pass, 1234)
+    player = self[email]
+    player && player[:digest].to_i == digest.to_i ? player : false
+  end
+
+  def self.verified?(email)
+    player = self[email]
+    player && player[:code] == "!"
+  end
+end
diff --git a/event_bus.rb b/event_bus.rb
new file mode 100644
index 0000000..d9466d1
--- /dev/null
+++ b/event_bus.rb
@@ -0,0 +1,12 @@
+# Event bus
+module EventBus
+  @events = {}
+
+  def self.on(event, &callback)
+    @events[event] = callback
+  end
+
+  def self.get(event, *args)
+    @events[event]&.call(*args)
+  end
+end
diff --git a/game_logic.rb b/game_logic.rb
new file mode 100644
index 0000000..76219f3
--- /dev/null
+++ b/game_logic.rb
@@ -0,0 +1,100 @@
+require "xxhash"
+
+# Game logic main class
+class GameLogic
+  @seed = rand(111_111..999_999)
+  @pos = {
+    board: {},
+    lost: {},
+    cache: {},
+  }
+
+  # Returns a pseudorandom number between 0 and 100
+  def self.hash(data)
+    XXhash.xxh32(data.to_s, @seed) % 100
+  end
+
+  def self.reset_pos
+    @pos.each_value(&:clear)
+  end
+
+  def self.reveal(g_x, g_y)
+    l_x = ((g_x % 9) + 9) % 9
+    l_y = ((g_y % 9) + 9) % 9
+    s_x = (g_x / 9).floor
+    s_y = (g_y / 9).floor
+
+    return if @pos.board["#{s_x}:#{s_y}"] == true
+    build_sector(s_x, s_y) if @pos.board["#{s_x}:#{s_y}"].nil?
+    return if @pos.board["#{s_x}:#{s_y}"][l_x][l_y][1] || @pos.board["#{s_x}:#{s_y}"][l_x][l_y][2]
+
+    if @pos.board["#{s_x}:#{s_y}"][l_x][l_y][0] == -1
+      @pos.lost["#{s_x}:#{s_y}"] = 1
+    elsif @pos.board["#{s_x}:#{s_y}"][l_x][l_y][0].zero?
+      (-1..1).each do |x|
+        (-1..1).each do |y|
+          next if x.zero? && y.zero?
+          reveal(g_x + x, g_y + y)
+        end
+      end
+    else
+      @pos.board["#{s_x}:#{s_y}"][l_x][l_y][1] = true
+    end
+
+    @pos.board["#{s_x}:#{s_y}"] = true if solved?(s_x, s_y)
+  end
+
+  def self.solved?(s_x, s_y)
+    (0..8).each do |l_x|
+      (0..8).each do |l_y|
+        return false if !@pos.board["#{s_x}:#{s_y}"][l_x][l_y][1] && @pos.board["#{s_x}:#{s_y}"][l_x][l_y][0] != -1
+      end
+    end
+    true
+  end
+
+  def self.count(g_x, g_y)
+    sum = 0
+    (-1..1).each do |x|
+      (-1..1).each do |y|
+        next if x.zero? && y.zero?
+        sum += 1 if mine?(g_x + x, g_y + y)
+      end
+    end
+    sum
+  end
+
+  def self.build_sector(s_x, s_y)
+    @pos.board["#{s_x}:#{s_y}"] = []
+    (0..8).each do |l_x|
+      @pos.board["#{s_x}:#{s_y}"][l_x] = []
+      (0..8).each do |l_y|
+        g_x = l_x + s_x * 9
+        g_y = l_y + s_y * 9
+        @pos.board["#{s_x}:#{s_y}"][l_x][l_y] = [
+          mine?(g_x, g_y) ? -1 : count(g_x, g_y),
+          false, false,
+        ]
+      end
+    end
+  end
+
+  def self.build_cache(s_x, s_y)
+    return if @pos.cache["#{s_x}:#{s_y}"]
+    return unless @pos.board["#{s_x}:#{s_y}"] == 1
+    @pos.cache["#{s_x}:#{s_y}"] = []
+    (0..8).each do |l_x|
+      @pos.cache["#{s_x}:#{s_y}"][l_x] = []
+      (0..8).each do |l_y|
+        g_x = l_x + s_x * 9
+        g_y = l_y + s_y * 9
+        @pos.cache["#{s_x}:#{s_y}"][l_x][l_y] =
+          mine?(g_x, g_y) ? [-1, false, true] : [count(g_x, g_y), true, false]
+      end
+    end
+  end
+
+  def self.mine?(g_x, g_y)
+    g_x == 4 || g_y == 4 ? false : hash("#{g_x}:#{g_y}") < 17
+  end
+end
diff --git a/log/puma.stderr.log b/log/puma.stderr.log
new file mode 100644
index 0000000..5682dad
--- /dev/null
+++ b/log/puma.stderr.log
@@ -0,0 +1,60 @@
+=== puma startup: 2025-06-19 18:12:41 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:13:06 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:13:21 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:13:35 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:15:41 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:15:52 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:16:47 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:17:35 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:18:08 +0300 ===
+127.0.0.1 - - [19/Jun/2025:18:18:17 +0300] "GET / HTTP/1.1" 200 460 0.0036
+127.0.0.1 - - [19/Jun/2025:18:18:17 +0300] "GET / HTTP/1.1" 304 - 0.0010
+127.0.0.1 - - [19/Jun/2025:18:18:18 +0300] "GET / HTTP/1.1" 304 - 0.0004
+127.0.0.1 - - [19/Jun/2025:18:18:18 +0300] "GET / HTTP/1.1" 304 - 0.0005
+127.0.0.1 - - [19/Jun/2025:18:18:19 +0300] "GET / HTTP/1.1" 304 - 0.0008
+127.0.0.1 - - [19/Jun/2025:18:18:19 +0300] "GET / HTTP/1.1" 304 - 0.0005
+127.0.0.1 - - [19/Jun/2025:18:18:19 +0300] "GET / HTTP/1.1" 304 - 0.0005
+127.0.0.1 - - [19/Jun/2025:18:18:20 +0300] "GET / HTTP/1.1" 304 - 0.0006
+127.0.0.1 - - [19/Jun/2025:18:18:20 +0300] "GET / HTTP/1.1" 304 - 0.0010
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:19:57 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:21:11 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:22:09 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:22:45 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:23:15 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:23:34 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-19 18:23:45 +0300 ===
+127.0.0.1 - - [19/Jun/2025:18:24:05 +0300] "GET / HTTP/1.1" 304 - 0.0032
+127.0.0.1 - - [19/Jun/2025:18:32:41 +0300] "GET / HTTP/1.1" 304 - 0.0006
+127.0.0.1 - - [19/Jun/2025:23:53:35 +0300] "GET / HTTP/1.1" 304 - 0.0005
+=== puma startup: 2025-06-20 23:53:14 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-20 23:53:29 +0300 ===
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-20 23:53:35 +0300 ===
+127.0.0.1 - - [20/Jun/2025:23:53:55 +0300] "GET / HTTP/1.1" 304 - 0.0024
+127.0.0.1 - - [20/Jun/2025:23:53:55 +0300] "GET /src/js/game_logic.js HTTP/1.1" 304 - 0.0005
+127.0.0.1 - - [20/Jun/2025:23:53:55 +0300] "GET /src/js/game_renderer.js HTTP/1.1" 304 - 0.0064
+== Sinatra has ended his set (crowd applauds)
+=== puma startup: 2025-06-21 14:36:03 +0300 ===
+127.0.0.1 - - [21/Jun/2025:14:36:35 +0300] "GET / HTTP/1.1" 304 - 0.0036
+127.0.0.1 - - [21/Jun/2025:14:36:35 +0300] "GET /src/js/event_handler.js HTTP/1.1" 304 - 0.0010
+127.0.0.1 - - [21/Jun/2025:14:36:35 +0300] "GET /src/js/ui_renderer.js HTTP/1.1" 304 - 0.0081
+127.0.0.1 - - [21/Jun/2025:14:36:35 +0300] "GET /src/js/saver.js HTTP/1.1" 304 - 0.0009
+127.0.0.1 - - [21/Jun/2025:14:36:36 +0300] "GET / HTTP/1.1" 304 - 0.0007
+127.0.0.1 - - [21/Jun/2025:14:36:36 +0300] "GET / HTTP/1.1" 304 - 0.0006
+== Sinatra has ended his set (crowd applauds)
diff --git a/log/puma.stdout.log b/log/puma.stdout.log
new file mode 100644
index 0000000..4956e38
--- /dev/null
+++ b/log/puma.stdout.log
@@ -0,0 +1,47 @@
+=== puma startup: 2025-06-19 18:12:41 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma shutdown: 2025-06-19 18:13:05 +0300 ===
+- Goodbye!
+=== puma startup: 2025-06-19 18:13:06 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma shutdown: 2025-06-19 18:13:13 +0300 ===
+- Goodbye!
+=== puma startup: 2025-06-19 18:13:21 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:13:35 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:15:41 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:15:52 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:16:47 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:17:35 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma shutdown: 2025-06-19 18:17:44 +0300 ===
+- Goodbye!
+=== puma startup: 2025-06-19 18:18:08 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:19:57 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:21:11 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:22:09 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:22:45 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:23:15 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma shutdown: 2025-06-19 18:23:22 +0300 ===
+- Goodbye!
+=== puma startup: 2025-06-19 18:23:34 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-19 18:23:45 +0300 ===
+=== puma startup: 2025-06-20 23:53:14 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-20 23:53:29 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-20 23:53:35 +0300 ===
+- Gracefully stopping, waiting for requests to finish
+=== puma startup: 2025-06-21 14:36:03 +0300 ===
+- Gracefully stopping, waiting for requests to finish
diff --git a/main.rb b/main.rb
new file mode 100644
index 0000000..5f38633
--- /dev/null
+++ b/main.rb
@@ -0,0 +1,7 @@
+require "sinatra"
+
+set :public_folder, "public"
+
+get "/" do
+  send_file "index.html"
+end
diff --git a/src/assets/img/logo_large.png b/public/src/assets/img/logo_large.png
similarity index 100%
rename from src/assets/img/logo_large.png
rename to public/src/assets/img/logo_large.png
diff --git a/src/assets/img/logo_sm.png b/public/src/assets/img/logo_sm.png
similarity index 100%
rename from src/assets/img/logo_sm.png
rename to public/src/assets/img/logo_sm.png
diff --git a/src/assets/img/minesweeper.png b/public/src/assets/img/minesweeper.png
similarity index 100%
rename from src/assets/img/minesweeper.png
rename to public/src/assets/img/minesweeper.png
diff --git a/src/assets/style.css b/public/src/assets/style.css
similarity index 100%
rename from src/assets/style.css
rename to public/src/assets/style.css
diff --git a/src/js/constants.js b/public/src/js/constants.js
similarity index 100%
rename from src/js/constants.js
rename to public/src/js/constants.js
diff --git a/src/js/event_bus.js b/public/src/js/event_bus.js
similarity index 100%
rename from src/js/event_bus.js
rename to public/src/js/event_bus.js
diff --git a/src/js/event_handler.js b/public/src/js/event_handler.js
similarity index 100%
rename from src/js/event_handler.js
rename to public/src/js/event_handler.js
diff --git a/src/js/game_controller.js b/public/src/js/game_controller.js
similarity index 100%
rename from src/js/game_controller.js
rename to public/src/js/game_controller.js
diff --git a/src/js/game_logic.js b/public/src/js/game_logic.js
similarity index 100%
rename from src/js/game_logic.js
rename to public/src/js/game_logic.js
diff --git a/src/js/game_renderer.js b/public/src/js/game_renderer.js
similarity index 100%
rename from src/js/game_renderer.js
rename to public/src/js/game_renderer.js
diff --git a/src/js/index.js b/public/src/js/index.js
similarity index 100%
rename from src/js/index.js
rename to public/src/js/index.js
diff --git a/src/js/saver.js b/public/src/js/saver.js
similarity index 100%
rename from src/js/saver.js
rename to public/src/js/saver.js
diff --git a/src/js/third_party_utils.js b/public/src/js/third_party_utils.js
similarity index 100%
rename from src/js/third_party_utils.js
rename to public/src/js/third_party_utils.js
diff --git a/src/js/ui_renderer.js b/public/src/js/ui_renderer.js
similarity index 100%
rename from src/js/ui_renderer.js
rename to public/src/js/ui_renderer.js
diff --git a/src/js/utils.js b/public/src/js/utils.js
similarity index 100%
rename from src/js/utils.js
rename to public/src/js/utils.js
diff --git a/run.fish b/run.fish
new file mode 100644
index 0000000..e334d9d
--- /dev/null
+++ b/run.fish
@@ -0,0 +1,31 @@
+set pipe_path /tmp/infin
+set oldsum (cat (find . -name '*.rb' | sort) | md5sum)
+if not test -p infinsweeper.db
+  sqlite3 infinsweeper.db < schema.sql
+end
+pkill ruby
+ruby main.rb -p8080 &
+if not test -p $pipe_path
+  touch $pipe_path
+end
+while true
+  sleep 1
+  set newsum (cat (find . -name '*.rb' | sort) | md5sum)
+  if test "$oldsum" != "$newsum"
+    set oldsum $newsum
+    pkill ruby
+    ruby main.rb -p8080 &
+  end
+  if set line (cat $pipe_path)
+    echo $line
+    if test "$line" = "die"
+      pkill ruby
+      echo "" > $pipe_path
+      exit
+    end
+    if test "$line" = "open"
+      echo "" > $pipe_path
+      xdg-open http://localhost:8080
+    end
+  end
+end
diff --git a/schema.sql b/schema.sql
new file mode 100644
index 0000000..9fa6a13
--- /dev/null
+++ b/schema.sql
@@ -0,0 +1,7 @@
+CREATE TABLE Players (
+  email TEXT PRIMARY KEY,
+  username TEXT UNIQUE,
+  digest BLOB,
+  data BLOB,
+  code TEXT
+);