diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index d4b3c96..1f4d4b9 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -7,7 +7,7 @@ on:
     branches: [ "master" ]
 
 jobs:
-  test:
+  rubocop:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -15,9 +15,22 @@ jobs:
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: '3.3'
+          bundler-cache: true
       - name: Install dependencies
         run: bundle install
       - name: Run cops
         run: bundle exec rubocop
+
+  specs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.3'
+          bundler-cache: true
+      - name: Install dependencies
+        run: bundle install
       - name: Run specs
         run: bundle exec rspec
diff --git a/.gitignore b/.gitignore
index 8478a0a..21befb3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 .byebug_history
 etc
 .rspec_status
+tmp
diff --git a/Gemfile b/Gemfile
index 12ad06b..9a9e1ac 100644
--- a/Gemfile
+++ b/Gemfile
@@ -13,4 +13,5 @@ group :development do
   gem 'rspec', '~> 3.13'
   gem 'rubocop', '~> 1.63'
   gem 'rubocop-rspec', '~> 2.29', '>= 2.29.2'
+  gem 'super_diff', '~> 0.12.1'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 47b6e57..a4363be 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,6 +2,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.2)
+    attr_extras (7.1.0)
     base64 (0.2.0)
     byebug (11.1.3)
     config (5.4.0)
@@ -15,10 +16,13 @@ GEM
     mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)
     nio4r (2.7.2)
+    optimist (3.1.0)
     parallel (1.24.0)
     parser (3.3.1.0)
       ast (~> 2.4.1)
       racc
+    patience_diff (1.2.0)
+      optimist (~> 3.0)
     puma (6.4.2)
       nio4r (~> 2.0)
     racc (1.7.3)
@@ -76,6 +80,10 @@ GEM
       rack-protection (= 4.0.0)
       rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
+    super_diff (0.12.1)
+      attr_extras (>= 6.2.4)
+      diff-lcs
+      patience_diff
     tilt (2.3.0)
     unicode-display_width (2.5.0)
 
@@ -93,6 +101,7 @@ DEPENDENCIES
   rubocop (~> 1.63)
   rubocop-rspec (~> 2.29, >= 2.29.2)
   sinatra (~> 4.0)
+  super_diff (~> 0.12.1)
 
 BUNDLED WITH
    2.5.9
diff --git a/README.md b/README.md
index c7bd987..afe7a68 100644
--- a/README.md
+++ b/README.md
@@ -52,17 +52,22 @@ Returns an array with all clients on the server
 Example response:
 
 ```json
-{
-  "6": {
-    "id": 6,
-    "address": "10.8.0.7",
+[
+  {
+    "id": 15,
+    "server_public_key": "server_public_key",
+    "address": "10.8.0.16/24",
     "private_key": "private_key",
-    "public_key": "public_key",
     "preshared_key": "preshared_key",
+    "allowed_ips": "0.0.0.0/0, ::/0",
+    "dns": "1.1.1.1",
+    "persistent_keepalive": 0,
+    "endpoint": "0.0.0.0:51820",
     "data": {
-      "params": "value"
+      "params1": "value1"
     }
-}
+  }
+]
 ```
 
 ### POST /clients
diff --git a/VERSION b/VERSION
index 7a5e833..02bf650 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-v0.1.4
\ No newline at end of file
+v0.1.5
\ No newline at end of file
diff --git a/app/clients_controller.rb b/app/clients_controller.rb
index 1678783..2756a64 100644
--- a/app/clients_controller.rb
+++ b/app/clients_controller.rb
@@ -9,7 +9,7 @@ def initialize
   end
 
   def index
-    wire_guard.all_configs.to_json
+    ClientsSerializer.each_serialize(wire_guard.all_configs, wire_guard.server_public_key)
   end
 
   def create(params)
diff --git a/app/clients_serializer.rb b/app/clients_serializer.rb
index 0a47328..40e95a5 100644
--- a/app/clients_serializer.rb
+++ b/app/clients_serializer.rb
@@ -12,17 +12,60 @@ def self.serialize(client_config, server_public_key)
     new(client_config, server_public_key).client.to_json
   end
 
+  def self.each_serialize(client_config, server_public_key)
+    new(client_config, server_public_key).clients.to_json
+  end
+
+  # NOTE: If an instance of a class is created through the each_serialize method,
+  # then the client_config variable will contain a hash with configs of the type:
+  # {
+  #  '1' => {
+  #    id: 1,
+  #    address: '10.8.0.2',
+  #    private_key: '1',
+  #    public_key: '2',
+  #    preshared_key: '3',
+  #    data: {}
+  #  },
+  #  '2' => {
+  #    id: 2,
+  #    address: '10.8.0.3',
+  #    private_key: '1',
+  #    public_key: '2',
+  #    preshared_key: '3',
+  #    data: {}
+  #  }
+  # }
   def initialize(client_config, server_public_key)
     @client_config = stringify_keys(client_config)
     @server_public_key = server_public_key
   end
 
+  def clients # rubocop:disable Metrics/MethodLength
+    client_config.map do |_config_id, config|
+      {
+        id: config['id'],
+        server_public_key:,
+        address: "#{config['address']}/24",
+        private_key: config['private_key'],
+        public_key: config['public_key'],
+        preshared_key: config['preshared_key'],
+        allowed_ips: WG_ALLOWED_IPS,
+        dns: DNS,
+        persistent_keepalive: WG_PERSISTENT_KEEPALIVE,
+        endpoint: "#{WG_HOST}:#{WG_PORT}",
+        data: config['data']
+      }
+    end
+  end
+
   def client # rubocop:disable Metrics/MethodLength
     {
       id: client_config['id'],
       server_public_key:,
       address: "#{client_config['address']}/24",
       private_key: client_config['private_key'],
+      public_key: client_config['public_key'],
       preshared_key: client_config['preshared_key'],
       allowed_ips: WG_ALLOWED_IPS,
       dns: DNS,
diff --git a/config/settings/test.yaml b/config/settings/test.yaml
index f0d51f2..dac865e 100644
--- a/config/settings/test.yaml
+++ b/config/settings/test.yaml
@@ -1,4 +1,4 @@
-wg_path: 'etc'
+wg_path: 'tmp/etc'
 wg_device: 'eth0'
 wg_default_address: '10.8.0.x'
 wg_allowed_ips: '0.0.0.0/0, ::/0'
diff --git a/lib/wire_guard/server.rb b/lib/wire_guard/server.rb
index 4a7aec2..be03169 100644
--- a/lib/wire_guard/server.rb
+++ b/lib/wire_guard/server.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'fileutils'
 require_relative 'config_builder'
 require_relative 'key_generator'
 require_relative 'config_updater'
diff --git a/spec/app/clients_controller_spec.rb b/spec/app/clients_controller_spec.rb
new file mode 100644
index 0000000..4713d97
--- /dev/null
+++ b/spec/app/clients_controller_spec.rb
@@ -0,0 +1,115 @@
+# frozen_string_literal: true
+
+RSpec.describe ClientsController do
+  subject(:controller) { described_class.new }
+
+  let(:wg_conf_path) { "#{Settings.wg_path}/wg0.json" }
+
+  before do
+    allow(WireGuard::ConfigUpdater).to receive(:update)
+    allow(WireGuard::KeyGenerator).to receive_messages(wg_genkey: 'wg_genkey', wg_pubkey: 'wg_pubkey',
+                                                       wg_genpsk: 'wg_genpsk')
+  end
+
+  after do
+    FileUtils.rm_rf(wg_conf_path)
+  end
+
+  describe '#index' do
+    context 'when there is no configuration file' do
+      let(:expected_result) do
+        {
+          server: {
+            private_key: 'wg_genkey',
+            public_key: 'wg_pubkey',
+            address: '10.8.0.1'
+          },
+          configs: {
+            last_id: 0,
+            last_address: '10.8.0.1'
+          }
+        }
+      end
+
+      it 'creates a configuration file and returns an empty array' do # rubocop:disable RSpec/MultipleExpectations
+        result = controller.index
+
+        expect(result).to eq([].to_json)
+
+        config = File.read(wg_conf_path)
+
+        expect(config).to eq(JSON.pretty_generate(expected_result))
+      end
+    end
+
+    context 'when there is already a configuration file without clients' do
+      before do
+        FileUtils.cp('spec/fixtures/empty_wg0.json', wg_conf_path)
+      end
+
+      it 'returns an empty array' do
+        expect(controller.index).to eq([].to_json)
+      end
+    end
+
+    context 'when there is already a configuration file with clients' do
+      before do
+        FileUtils.cp('spec/fixtures/wg0.json', wg_conf_path)
+      end
+
+      let(:expected_result) do
+        [
+          {
+            id: 1,
+            server_public_key: 'uygGKpQt7gOwrP+bqkiXytafHiM+XqFGc0jtZVJ5bnw=',
+            address: '10.8.0.2/24',
+            private_key: 'MJn6fwoyqG8S6wsrJzWrUow4leZuEM9O8s+G+kcXElU=',
+            public_key: 'LiXk4UOfnScgf4UnkcYNcz4wWeqTOW1UrHKRVhZ1OXg=',
+            preshared_key: '3UzAMA6mLIGjHOImShNb5tWlkwxsha8LZZP7dm49meQ=',
+            allowed_ips: '0.0.0.0/0, ::/0',
+            dns: '1.1.1.1',
+            persistent_keepalive: 0,
+            endpoint: '2.2.2.2:51820',
+            data: {
+              lol: 'kek'
+            }
+          },
+          {
+            id: 2,
+            server_public_key: 'uygGKpQt7gOwrP+bqkiXytafHiM+XqFGc0jtZVJ5bnw=',
+            address: '10.8.0.3/24',
+            private_key: 'aN7ye98FKrmydwfA6tHgHE1PbiidWzUJ9cltnies8F4=',
+            public_key: 'hvIyIW2o8JROVKuY2yYFdUn0oA+43aLuT8KCy0YbORE=',
+            preshared_key: 'dVW/5kF8wnsx0zAwR4uPIa06btACxpQ/rHBL1B3qPnk=',
+            allowed_ips: '0.0.0.0/0, ::/0',
+            dns: '1.1.1.1',
+            persistent_keepalive: 0,
+            endpoint: '2.2.2.2:51820',
+            data: {
+              cheburek: 'hah'
+            }
+          },
+          {
+            id: 3,
+            server_public_key: 'uygGKpQt7gOwrP+bqkiXytafHiM+XqFGc0jtZVJ5bnw=',
+            address: '10.8.0.4/24',
+            private_key: 'eF3Owsqd5MGAIXjmALGBi8ea8mkFUmAiyh80U3hVXn8=',
+            public_key: 'bPKBg66uC1J2hlkE31Of5wnkg+IjowVXgoLcjcLn0js=',
+            preshared_key: 'IyVg7fktkSBxJ0uK82j6nlI7Vmo0E53eBmYZ723/45E=',
+            allowed_ips: '0.0.0.0/0, ::/0',
+            dns: '1.1.1.1',
+            persistent_keepalive: 0,
+            endpoint: '2.2.2.2:51820',
+            data: {
+              key: 'value'
+            }
+          }
+        ]
+      end
+
+      it 'returns a serialized array with all clients' do
+        expect(controller.index).to eq(expected_result.to_json)
+      end
+    end
+  end
+end
diff --git a/spec/app/clients_serializer_spec.rb b/spec/app/clients_serializer_spec.rb
index 91fb678..dc5c7bf 100644
--- a/spec/app/clients_serializer_spec.rb
+++ b/spec/app/clients_serializer_spec.rb
@@ -1,37 +1,100 @@
 # frozen_string_literal: true
 
 RSpec.describe ClientsSerializer do
-  subject(:serialize) { described_class.serialize(config, key) }
-
-  let(:config) do
-    {
-      id: 1,
-      address: '10.8.0.2',
-      private_key: '1',
-      public_key: '2',
-      preshared_key: '3',
-      data: {}
-    }
-  end
-
   let(:key) { '4' }
 
-  let(:excepted_result) do
-    {
-      id: 1,
-      server_public_key: '4',
-      address: '10.8.0.2/24',
-      private_key: '1',
-      preshared_key: '3',
-      allowed_ips: '0.0.0.0/0, ::/0',
-      dns: '1.1.1.1',
-      persistent_keepalive: 0,
-      endpoint: '2.2.2.2:51820',
-      data: {}
-    }.to_json
+  describe '#serialize' do
+    subject(:serialize) { described_class.serialize(config, key) }
+
+    let(:config) do
+      {
+        id: 1,
+        address: '10.8.0.2',
+        private_key: '1',
+        public_key: '2',
+        preshared_key: '3',
+        data: {}
+      }
+    end
+
+    let(:expected_result) do
+      {
+        id: 1,
+        server_public_key: '4',
+        address: '10.8.0.2/24',
+        private_key: '1',
+        public_key: '2',
+        preshared_key: '3',
+        allowed_ips: '0.0.0.0/0, ::/0',
+        dns: '1.1.1.1',
+        persistent_keepalive: 0,
+        endpoint: '2.2.2.2:51820',
+        data: {}
+      }.to_json
+    end
+
+    it 'serializes one config' do
+      expect(serialize).to eq(expected_result)
+    end
   end
 
-  it do
-    expect(serialize).to eq(excepted_result)
+  describe '#each_serialize' do
+    subject(:serialize) { described_class.each_serialize(config, key) }
+
+    let(:config) do
+      {
+        '1' => {
+          id: 1,
+          address: '10.8.0.2',
+          private_key: '1',
+          public_key: '2',
+          preshared_key: '3',
+          data: {}
+        },
+        '2' => {
+          id: 2,
+          address: '10.8.0.3',
+          private_key: '1',
+          public_key: '2',
+          preshared_key: '3',
+          data: {}
+        }
+      }
+    end
+
+    let(:expected_result) do
+      [
+        {
+          id: 1,
+          server_public_key: '4',
+          address: '10.8.0.2/24',
+          private_key: '1',
+          public_key: '2',
+          preshared_key: '3',
+          allowed_ips: '0.0.0.0/0, ::/0',
+          dns: '1.1.1.1',
+          persistent_keepalive: 0,
+          endpoint: '2.2.2.2:51820',
+          data: {}
+        },
+        {
+          id: 2,
+          server_public_key: '4',
+          address: '10.8.0.3/24',
+          private_key: '1',
+          public_key: '2',
+          preshared_key: '3',
+          allowed_ips: '0.0.0.0/0, ::/0',
+          dns: '1.1.1.1',
+          persistent_keepalive: 0,
+          endpoint: '2.2.2.2:51820',
+          data: {}
+        }
+      ]
+    end
+
+    it 'serializes multiple configs' do
+      expect(serialize).to eq(expected_result.to_json)
+    end
   end
 end
diff --git a/spec/fixtures/empty_wg0.json b/spec/fixtures/empty_wg0.json
new file mode 100644
index 0000000..0f1bb37
--- /dev/null
+++ b/spec/fixtures/empty_wg0.json
@@ -0,0 +1,11 @@
+{
+  "server": {
+    "private_key": "wg_genkey",
+    "public_key": "wg_pubkey",
+    "address": "10.8.0.1"
+  },
+  "configs": {
+    "last_id": 0,
+    "last_address": "10.8.0.1"
+  }
+}
\ No newline at end of file
diff --git a/spec/fixtures/wg0.json b/spec/fixtures/wg0.json
new file mode 100644
index 0000000..19074de
--- /dev/null
+++ b/spec/fixtures/wg0.json
@@ -0,0 +1,41 @@
+{
+  "server": {
+    "private_key": "6Mlqg+1Umojm7a4VvgIi+YMp4oPrWNnZ5HLRFu4my2w=",
+    "public_key": "uygGKpQt7gOwrP+bqkiXytafHiM+XqFGc0jtZVJ5bnw=",
+    "address": "10.8.0.1"
+  },
+  "configs": {
+    "last_id": 3,
+    "last_address": "10.8.0.4",
+    "1": {
+      "id": 1,
+      "address": "10.8.0.2",
+      "private_key": "MJn6fwoyqG8S6wsrJzWrUow4leZuEM9O8s+G+kcXElU=",
+      "public_key": "LiXk4UOfnScgf4UnkcYNcz4wWeqTOW1UrHKRVhZ1OXg=",
+      "preshared_key": "3UzAMA6mLIGjHOImShNb5tWlkwxsha8LZZP7dm49meQ=",
+      "data": {
+        "lol": "kek"
+      }
+    },
+    "2": {
+      "id": 2,
+      "address": "10.8.0.3",
+      "private_key": "aN7ye98FKrmydwfA6tHgHE1PbiidWzUJ9cltnies8F4=",
+      "public_key": "hvIyIW2o8JROVKuY2yYFdUn0oA+43aLuT8KCy0YbORE=",
+      "preshared_key": "dVW/5kF8wnsx0zAwR4uPIa06btACxpQ/rHBL1B3qPnk=",
+      "data": {
+        "cheburek": "hah"
+      }
+    },
+    "3": {
+      "id": 3,
+      "address": "10.8.0.4",
+      "private_key": "eF3Owsqd5MGAIXjmALGBi8ea8mkFUmAiyh80U3hVXn8=",
+      "public_key": "bPKBg66uC1J2hlkE31Of5wnkg+IjowVXgoLcjcLn0js=",
+      "preshared_key": "IyVg7fktkSBxJ0uK82j6nlI7Vmo0E53eBmYZ723/45E=",
+      "data": {
+        "key": "value"
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 6f0a27b..caaaf9a 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -3,9 +3,14 @@
 require 'json'
 require 'byebug'
 require 'config'
+require 'fileutils'
 Config.load_and_set_settings('config/settings/test.yaml')
 
 require_relative '../app/clients_serializer'
+require_relative '../app/clients_controller'
+require_relative '../lib/wire_guard/server'
+
+require 'super_diff/rspec'
 
 RSpec.configure do |config|
   config.example_status_persistence_file_path = '.rspec_status'