diff --git a/lib/zadarma.rb b/lib/zadarma.rb
new file mode 100644
index 0000000..470d3df
--- /dev/null
+++ b/lib/zadarma.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require 'zadarma/version'
+require 'zadarma/client'
+require 'zadarma/error'
+
+# The Zadarma module contains all the classes and methods for the Zadarma API client.
+module Zadarma
+end
diff --git a/lib/zadarma/client.rb b/lib/zadarma/client.rb
new file mode 100644
index 0000000..2e4043b
--- /dev/null
+++ b/lib/zadarma/client.rb
@@ -0,0 +1,361 @@
+# frozen_string_literal: true
+
+require 'json'
+require 'faraday'
+require 'openssl'
+require 'base64'
+require 'digest/md5'
+require 'cgi'
+
+require_relative 'resources/info'
+require_relative 'resources/pbx'
+require_relative 'resources/direct_numbers'
+require_relative 'resources/request'
+require_relative 'resources/sip'
+require_relative 'resources/sms'
+require_relative 'resources/statistics'
+require_relative 'resources/speech_recognition'
+require_relative 'resources/groups_of_documents'
+require_relative 'client/resources'
+require_relative 'client/http'
+
+module Zadarma
+  # The Client class is the main entry point for interacting with the Zadarma API.
+  class Client
+    include Resources
+    include Http
+
+    API_URL = 'https://api.zadarma.com'
+
+    # Initializes a new Client object.
+    #
+    # @param api_key [String] The Zadarma API key.
+    # @param api_secret [String] The Zadarma API secret.
+    def initialize(api_key:, api_secret:)
+      @api_key = api_key
+      @api_secret = api_secret
+    end
+
+    # Get the current account balance.
+    #
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_balance
+    def balance
+      info.balance
+    end
+
+    # Get the price for a call to a specific number.
+    #
+    # @param number [String] The destination number.
+    # @param caller_id [String] The caller ID.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_price
+    def price(number:, caller_id: nil)
+      info.price(number: number, caller_id: caller_id)
+    end
+
+    # Get a list of internal PBX numbers.
+    #
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_pbx_internal
+    def internal_numbers
+      pbx.internal
+    end
+
+    # Enable or disable call recording for a PBX extension.
+    #
+    # @param id [String] The PBX extension ID.
+    # @param status [String] The recording status.
+    # @param email [String] The email address to send the recording to.
+    # @param speech_recognition [String] The speech recognition status.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_pbx_record
+    def set_call_recording(id:, status:, email: nil, speech_recognition: nil)
+      pbx.set_call_recording(id: id, status: status, email: email, speech_recognition: speech_recognition)
+    end
+
+    # Request a call recording from the PBX.
+    #
+    # @param call_id [String] The call ID.
+    # @param pbx_call_id [String] The PBX call ID.
+    # @param lifetime [String] The lifetime of the recording.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_pbx_record_request
+    def pbx_record_request(call_id: nil, pbx_call_id: nil, lifetime: nil)
+      pbx.pbx_record_request(call_id: call_id, pbx_call_id: pbx_call_id, lifetime: lifetime)
+    end
+
+    # Get a list of direct numbers.
+    #
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_direct_numbers
+    def direct_numbers
+      direct_numbers_resource.all
+    end
+
+    # Get a list of countries for direct numbers.
+    #
+    # @param language [String] The language of the response.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_direct_number_countries
+    def direct_number_countries(language: nil)
+      direct_numbers_resource.countries(language: language)
+    end
+
+    # Get a list of direct numbers for a specific country.
+    #
+    # @param country [String] The country code.
+    # @param language [String] The language of the response.
+    # @param direction_id [String] The direction ID.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_direct_number_country
+    def direct_number_country(country:, language: nil, direction_id: nil)
+      direct_numbers_resource.country(country: country, language: language, direction_id: direction_id)
+    end
+
+    # Get a list of available direct numbers.
+    #
+    # @param direction_id [String] The direction ID.
+    # @param mask [String] The number mask.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_available_direct_numbers
+    def available_direct_numbers(direction_id:, mask: nil)
+      direct_numbers_resource.available(direction_id: direction_id, mask: mask)
+    end
+
+    # Order a direct number.
+    #
+    # @param params [Hash] The order parameters.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_order_direct_number
+    def order_direct_number(params)
+      direct_numbers_resource.order(params)
+    end
+
+    # Prolong a direct number.
+    #
+    # @param number [String] The direct number.
+    # @param months [String] The number of months to prolong the number for.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_prolong_direct_number
+    def prolong_direct_number(number:, months:)
+      direct_numbers_resource.prolong(number: number, months: months)
+    end
+
+    # Initiate a callback between two numbers.
+    #
+    # @param from [String] The source number.
+    # @param to [String] The destination number.
+    # @param sip [String] The SIP number.
+    # @param predicted [String] The predicted status.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_callback
+    def callback(from:, to:, sip: nil, predicted: nil)
+      request_resource.callback(from: from, to: to, sip: sip, predicted: predicted)
+    end
+
+    # Get a list of SIP numbers.
+    #
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_sips
+    def sips
+      sip.all
+    end
+
+    # Get the status of a SIP number.
+    #
+    # @param sip [String] The SIP number.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_sip_status
+    def sip_status(sip:)
+      self.sip.status(sip: sip)
+    end
+
+    # Create a SIP number.
+    #
+    # @param name [String] The SIP number name.
+    # @param password [String] The SIP number password.
+    # @param callerid [String] The SIP number caller ID.
+    # @param redirect_to_phone [String] The phone number to redirect to.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_create_sip
+    def create_sip(name:, password: nil, callerid: nil, redirect_to_phone: nil)
+      sip.create(name: name, password: password, callerid: callerid, redirect_to_phone: redirect_to_phone)
+    end
+
+    # Set the password for a SIP number.
+    #
+    # @param sip [String] The SIP number.
+    # @param value [String] The new password.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_set_sip_password
+    def set_sip_password(sip:, value:)
+      self.sip.password(sip: sip, value: value)
+    end
+
+    # Set the caller ID for a SIP number.
+    #
+    # @param id [String] The SIP number ID.
+    # @param number [String] The new caller ID.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_set_sip_caller_id
+    def set_sip_caller_id(id:, number:)
+      sip.set_caller_id(id: id, number: number)
+    end
+
+    # Get call forwarding information for a SIP number.
+    #
+    # @param id [String] The SIP number ID.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_redirection
+    def redirection(id: nil)
+      sip.redirection(id: id)
+    end
+
+    # Set call forwarding for a SIP number.
+    #
+    # @param id [String] The SIP number ID.
+    # @param status [String] The forwarding status.
+    # @param type [String] The forwarding type.
+    # @param number [String] The forwarding number.
+    # @param condition [String] The forwarding condition.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_set_redirection
+    def set_redirection(id:, status:, type: nil, number: nil, condition: nil)
+      sip.set_redirection(id: id, status: status, type: type, number: number, condition: condition)
+    end
+
+    # Send an SMS message.
+    #
+    # @param number [String] The destination number.
+    # @param message [String] The message text.
+    # @param sender [String] The sender ID.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_send_sms
+    def send_sms(number:, message:, sender: nil)
+      sms.send_sms(number: number, message: message, sender: sender)
+    end
+
+    # Get overall call statistics.
+    #
+    # @param params [Hash] The statistics parameters.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_statistics
+    def statistics(params)
+      statistics_resource.statistics(params)
+    end
+
+    # Get PBX call statistics.
+    #
+    # @param params [Hash] The statistics parameters.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_pbx_statistics
+    def pbx_statistics(params)
+      statistics_resource.pbx_statistics(params)
+    end
+
+    # Get speech recognition results.
+    #
+    # @param call_id [String] The call ID.
+    # @param lang [String] The language of the speech.
+    # @param return_results [String] Whether to return the results.
+    # @param alternatives [String] Whether to return alternative results.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_get_speech_recognition
+    def get_speech_recognition(call_id:, lang: nil, return_results: nil, alternatives: nil)
+      speech_recognition_resource.get(call_id: call_id, lang: lang, return_results: return_results,
+                                      alternatives: alternatives)
+    end
+
+    # Initiate speech recognition.
+    #
+    # @param call_id [String] The call ID.
+    # @param lang [String] The language of the speech.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_initiate_speech_recognition
+    def initiate_speech_recognition(call_id:, lang: nil)
+      speech_recognition_resource.initiate(call_id: call_id, lang: lang)
+    end
+
+    # Get a list of document files.
+    #
+    # @param group_id [String] The group ID.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_document_files
+    def document_files(group_id: nil)
+      groups_of_documents_resource.files(group_id: group_id)
+    end
+
+    # Get a list of document groups.
+    #
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_document_groups
+    def document_groups
+      groups_of_documents_resource.list
+    end
+
+    # Get a document group.
+    #
+    # @param id [String] The group ID.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_get_document_group
+    def get_document_group(id:)
+      groups_of_documents_resource.get(id: id)
+    end
+
+    # Create a document group.
+    #
+    # @param params [Hash] The group parameters.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_create_document_group
+    def create_document_group(params:)
+      groups_of_documents_resource.create(params: params)
+    end
+
+    # Update a document group.
+    #
+    # @param id [String] The group ID.
+    # @param params [Hash] The group parameters.
+    # @return [Hash] The API response.
+    # @see https://zadarma.com/en/support/api/#api_update_document_group
+    def update_document_group(id:, params:)
+      groups_of_documents_resource.update(id: id, params: params)
+    end
+
+    # Make a GET request to the Zadarma API.
+    #
+    # @param path [String] The API endpoint path.
+    # @param params [Hash] The request parameters.
+    # @return [Hash] The API response.
+    def get(path, params = {})
+      request(:get, path, params)
+    end
+
+    # Make a POST request to the Zadarma API.
+    #
+    # @param path [String] The API endpoint path.
+    # @param params [Hash] The request parameters.
+    # @return [Hash] The API response.
+    def post(path, params = {})
+      request(:post, path, params)
+    end
+
+    # Make a PUT request to the Zadarma API.
+    #
+    # @param path [String] The API endpoint path.
+    # @param params [Hash] The request parameters.
+    # @return [Hash] The API response.
+    def put(path, params = {})
+      request(:put, path, params)
+    end
+
+    # Make a DELETE request to the Zadarma API.
+    #
+    # @param path [String] The API endpoint path.
+    # @param params [Hash] The request parameters.
+    # @return [Hash] The API response.
+    def delete(path, params = {})
+      request(:delete, path, params)
+    end
+  end
+end
diff --git a/lib/zadarma/client/http.rb b/lib/zadarma/client/http.rb
new file mode 100644
index 0000000..268cc3d
--- /dev/null
+++ b/lib/zadarma/client/http.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+module Zadarma
+  class Client
+    # A module for handling HTTP requests to the Zadarma API.
+    module Http
+      private
+
+      def request(method, path, params)
+        raise 'No API key or secret provided' unless @api_key && @api_secret
+
+        sorted_params = params.sort.to_h
+        query_string = to_query(sorted_params)
+        signature = generate_signature(path, query_string)
+
+        response = execute_request(method, path, sorted_params, signature)
+
+        handle_response(response)
+      end
+
+      def execute_request(method, path, params, signature)
+        connection.send(method) do |req|
+          req.url path
+          req.headers['Authorization'] = "#{@api_key}:#{signature}"
+          if %i[post put].include?(method)
+            req.body = params
+          else
+            req.params = params
+          end
+        end
+      end
+
+      def connection
+        @connection ||= Faraday.new(url: API_URL) do |faraday|
+          faraday.request :url_encoded
+          faraday.adapter Faraday.default_adapter
+        end
+      end
+
+      def generate_signature(path, query_string)
+        string_to_sign = path + query_string + Digest::MD5.hexdigest(query_string)
+        hmac = OpenSSL::HMAC.hexdigest('sha1', @api_secret, string_to_sign)
+        Base64.strict_encode64(hmac)
+      end
+
+      def to_query(hash)
+        hash.map { |k, v| "#{CGI.escape(k.to_s)}=#{CGI.escape(v.to_s)}" }.join('&')
+      end
+
+      def handle_response(response)
+        raise Zadarma::Error, "API Error: #{response.status} - #{response.body}" unless response.success?
+
+        body = JSON.parse(response.body)
+        raise Zadarma::Error, "API Error: #{body['message']}" if body['status'] == 'error'
+
+        body
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/client/resources.rb b/lib/zadarma/client/resources.rb
new file mode 100644
index 0000000..e758580
--- /dev/null
+++ b/lib/zadarma/client/resources.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+module Zadarma
+  class Client
+    # A module for accessing the various resources of the Zadarma API.
+    module Resources
+      private
+
+      # @!group Resources
+      # @!macro [attach] zadarma.resource
+      #   @return [Zadarma::Resources::$1] the $1 resource
+
+      def info
+        ::Zadarma::Resources::Info.new(client: self)
+      end
+
+      def pbx
+        ::Zadarma::Resources::Pbx.new(client: self)
+      end
+
+      def direct_numbers_resource
+        ::Zadarma::Resources::DirectNumbers.new(client: self)
+      end
+
+      def request_resource
+        ::Zadarma::Resources::Request.new(client: self)
+      end
+
+      def sip
+        ::Zadarma::Resources::Sip.new(client: self)
+      end
+
+      def sms
+        ::Zadarma::Resources::Sms.new(client: self)
+      end
+
+      def statistics_resource
+        ::Zadarma::Resources::Statistics.new(client: self)
+      end
+
+      def speech_recognition_resource
+        ::Zadarma::Resources::SpeechRecognition.new(client: self)
+      end
+
+      def groups_of_documents_resource
+        ::Zadarma::Resources::GroupsOfDocuments.new(client: self)
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/error.rb b/lib/zadarma/error.rb
new file mode 100644
index 0000000..9635af3
--- /dev/null
+++ b/lib/zadarma/error.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module Zadarma
+  class Error < StandardError
+  end
+end
diff --git a/lib/zadarma/resources/direct_numbers.rb b/lib/zadarma/resources/direct_numbers.rb
new file mode 100644
index 0000000..713f395
--- /dev/null
+++ b/lib/zadarma/resources/direct_numbers.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+module Zadarma
+  module Resources
+    # The DirectNumbers resource allows you to manage virtual numbers.
+    class DirectNumbers
+      def initialize(client:)
+        @client = client
+      end
+
+      # Get information about the user's virtual numbers
+      # @return [Hash]
+      def all
+        @client.get('/v1/direct_numbers/')
+      end
+
+      # Get a list of countries where numbers can be ordered
+      # @param language [String] The language for the country names
+      # @return [Hash]
+      def countries(language: nil)
+        params = {}
+        params[:language] = language if language
+        @client.get('/v1/direct_numbers/countries/', params)
+      end
+
+      # Get a list of destinations in a country where a number can be ordered
+      # @param country [String] The ISO country code
+      # @param language [String] The language for the destination names
+      # @param direction_id [String] The direction ID
+      # @return [Hash]
+      def country(country:, language: nil, direction_id: nil)
+        params = { country: country }
+        params[:language] = language if language
+        params[:direction_id] = direction_id if direction_id
+        @client.get('/v1/direct_numbers/country/', params)
+      end
+
+      # Get a list of available numbers for a given direction
+      # @param direction_id [String] The direction ID
+      # @param mask [String] A mask for searching number matches
+      # @return [Hash]
+      def available(direction_id:, mask: nil)
+        params = {}
+        params[:mask] = mask if mask
+        @client.get("/v1/direct_numbers/available/#{direction_id}/", params)
+      end
+
+      # Order a virtual number
+      # @param params [Hash] The parameters for ordering a number
+      # @option params [String] :direction_id The direction/city ID
+      # @option params [String] :number_id The ID of the number to be connected
+      # @option params [String] :documents_group_id The ID of the group of user documents
+      # @option params [String] :purpose A text description of the purpose of number use
+      # @option params [String] :receive_sms '1' to enable SMS reception
+      # @option params [String] :period 'month' or '3month'
+      # @option params [String] :autorenew_period 'year' or 'month'
+      # @return [Hash]
+      def order(params)
+        @client.post('/v1/direct_numbers/order/', params)
+      end
+
+      # Prepay the number for the specified number of months
+      # @param number [String] The number to be prolonged
+      # @param months [Integer] The number of months
+      # @return [Hash]
+      def prolong(number:, months:)
+        @client.post('/v1/direct_numbers/prolong/', number: number, months: months)
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/resources/groups_of_documents.rb b/lib/zadarma/resources/groups_of_documents.rb
new file mode 100644
index 0000000..a905fc8
--- /dev/null
+++ b/lib/zadarma/resources/groups_of_documents.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module Zadarma
+  module Resources
+    # The GroupsOfDocuments resource allows you to manage groups of documents.
+    class GroupsOfDocuments
+      def initialize(client:)
+        @client = client
+      end
+
+      # Get the list of files/documents in the group of documents
+      # @param group_id [String] The group of documents ID
+      # @return [Hash]
+      def files(group_id: nil)
+        params = {}
+        params[:group_id] = group_id if group_id
+        @client.get('/v1/documents/files/', params)
+      end
+
+      # Get the list of groups of documents
+      # @return [Hash]
+      def list
+        @client.get('/v1/documents/groups/list/')
+      end
+
+      # Get information on a certain group
+      # @param id [String] The group ID
+      # @return [Hash]
+      def get(id:)
+        @client.get("/v1/documents/groups/get/#{id}/")
+      end
+
+      # Create a new group of documents
+      # @param params [Hash] The parameters for creating a new group of documents
+      # @return [Hash]
+      def create(params:)
+        @client.post('/v1/documents/groups/create/', params)
+      end
+
+      # Update a group of documents
+      # @param id [String] The group ID
+      # @param params [Hash] The parameters for updating a group of documents
+      # @return [Hash]
+      def update(id:, params:)
+        @client.put("/v1/documents/groups/update/#{id}/", params)
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/resources/info.rb b/lib/zadarma/resources/info.rb
new file mode 100644
index 0000000..78b4f9f
--- /dev/null
+++ b/lib/zadarma/resources/info.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module Zadarma
+  module Resources
+    # The Info resource provides access to user information, such as balance and call rates.
+    class Info
+      def initialize(client:)
+        @client = client
+      end
+
+      # Get the user's balance
+      # @return [Hash]
+      def balance
+        @client.get('/v1/info/balance/')
+      end
+
+      # Get the call rate for a given number
+      # @param number [String] The phone number
+      # @param caller_id [String] The CallerID to be used for the call
+      # @return [Hash]
+      def price(number:, caller_id: nil)
+        params = { number: number }
+        params[:caller_id] = caller_id if caller_id
+        @client.get('/v1/info/price/', params)
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/resources/pbx.rb b/lib/zadarma/resources/pbx.rb
new file mode 100644
index 0000000..37e0514
--- /dev/null
+++ b/lib/zadarma/resources/pbx.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module Zadarma
+  module Resources
+    # The Pbx resource allows you to manage your Zadarma PBX.
+    class Pbx
+      def initialize(client:)
+        @client = client
+      end
+
+      # Get the list of PBX internal numbers
+      # @return [Hash]
+      def internal
+        @client.get('/v1/pbx/internal/')
+      end
+
+      # Set the call recording for a PBX extension
+      # @param id [String] The PBX extension ID
+      # @param status [String] The call recording status ('on', 'off', etc.)
+      # @param email [String] The email address to send recordings to
+      # @param speech_recognition [String] The speech recognition settings
+      # @return [Hash]
+      def set_call_recording(id:, status:, email: nil, speech_recognition: nil)
+        params = { id: id, status: status }
+        params[:email] = email if email
+        params[:speech_recognition] = speech_recognition if speech_recognition
+        @client.put('/v1/pbx/internal/recording/', params)
+      end
+
+      # Request a call recording file
+      # @param call_id [String] The unique call ID
+      # @param pbx_call_id [String] The permanent ID of the external call to the PBX
+      # @param lifetime [Integer] The link's lifetime in seconds
+      # @return [Hash]
+      def pbx_record_request(call_id: nil, pbx_call_id: nil, lifetime: nil)
+        params = {}
+        params[:call_id] = call_id if call_id
+        params[:pbx_call_id] = pbx_call_id if pbx_call_id
+        params[:lifetime] = lifetime if lifetime
+        @client.get('/v1/pbx/record/request/', params)
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/resources/request.rb b/lib/zadarma/resources/request.rb
new file mode 100644
index 0000000..4c34a38
--- /dev/null
+++ b/lib/zadarma/resources/request.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Zadarma
+  module Resources
+    # The Request resource allows you to initiate callbacks.
+    class Request
+      def initialize(client:)
+        @client = client
+      end
+
+      # Request a callback
+      # @param from [String] Your phone/SIP number, the PBX extension or the PBX scenario
+      # @param to [String] The phone or SIP number that is being called
+      # @param sip [String] The SIP user's number or the PBX extension
+      # @param predicted [String] If specified, the request is predicted
+      # @return [Hash]
+      def callback(from:, to:, sip: nil, predicted: nil)
+        params = { from: from, to: to }
+        params[:sip] = sip if sip
+        params[:predicted] = predicted if predicted
+        @client.get('/v1/request/callback/', params)
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/resources/sip.rb b/lib/zadarma/resources/sip.rb
new file mode 100644
index 0000000..34f5602
--- /dev/null
+++ b/lib/zadarma/resources/sip.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+module Zadarma
+  module Resources
+    # The Sip resource allows you to manage your SIP numbers.
+    class Sip
+      def initialize(client:)
+        @client = client
+      end
+
+      # Get the list of user's SIP-numbers
+      # @return [Hash]
+      def all
+        @client.get('/v1/sip/')
+      end
+
+      # Set the CallerID for a SIP number
+      # @param id [String] The SIP ID
+      # @param number [String] The new CallerID
+      # @return [Hash]
+      def set_caller_id(id:, number:)
+        @client.put('/v1/sip/callerid/', id: id, number: number)
+      end
+
+      # Get call forwarding information for a SIP number
+      # @param id [String] The SIP ID
+      # @return [Hash]
+      def redirection(id: nil)
+        params = {}
+        params[:id] = id if id
+        @client.get('/v1/sip/redirection/', params)
+      end
+
+      # Set call forwarding for a SIP number
+      # @param id [String] The SIP ID
+      # @param status [String] The call forwarding status ('on' or 'off')
+      # @param type [String] The call forwarding type ('phone', 'voicemail', etc.)
+      # @param number [String] The destination number for call forwarding
+      # @param condition [String] The call forwarding condition ('always', 'noanswer', etc.)
+      # @return [Hash]
+      def set_redirection(id:, status:, type: nil, number: nil, condition: nil)
+        params = { id: id, status: status }
+        params[:type] = type if type
+        params[:number] = number if number
+        params[:condition] = condition if condition
+        @client.put('/v1/sip/redirection/', params)
+      end
+
+      # Get the online status of a SIP number
+      # @param sip [String] The SIP number
+      # @return [Hash]
+      def status(sip:)
+        @client.get("/v1/sip/#{sip}/status/")
+      end
+
+      # Create a new SIP number
+      # @param name [String] The displayed name for the new SIP number
+      # @param password [String] The password for the new SIP number
+      # @param callerid [String] The CallerID for the new SIP number
+      # @param redirect_to_phone [String] The phone number to redirect calls to
+      # @return [Hash]
+      def create(name:, password: nil, callerid: nil, redirect_to_phone: nil)
+        params = { name: name }
+        params[:password] = password if password
+        params[:callerid] = callerid if callerid
+        params[:redirect_to_phone] = redirect_to_phone if redirect_to_phone
+        @client.post('/v1/sip/create/', params)
+      end
+
+      # Change the password for a SIP number
+      # @param sip [String] The SIP number
+      # @param value [String] The new password
+      # @return [Hash]
+      def password(sip:, value:)
+        @client.put("/v1/sip/#{sip}/password/", value: value)
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/resources/sms.rb b/lib/zadarma/resources/sms.rb
new file mode 100644
index 0000000..e0972de
--- /dev/null
+++ b/lib/zadarma/resources/sms.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module Zadarma
+  module Resources
+    # The Sms resource allows you to send SMS messages.
+    class Sms
+      def initialize(client:)
+        @client = client
+      end
+
+      # Send an SMS message
+      # @param number [String] The destination phone number
+      # @param message [String] The SMS message text
+      # @param sender [String] The SMS sender (virtual number or text)
+      # @return [Hash]
+      def send_sms(number:, message:, sender: nil)
+        params = { number: number, message: message }
+        params[:sender] = sender if sender
+        @client.post('/v1/sms/send/', params)
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/resources/speech_recognition.rb b/lib/zadarma/resources/speech_recognition.rb
new file mode 100644
index 0000000..06dec86
--- /dev/null
+++ b/lib/zadarma/resources/speech_recognition.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module Zadarma
+  module Resources
+    # The SpeechRecognition resource allows you to manage speech recognition.
+    class SpeechRecognition
+      def initialize(client:)
+        @client = client
+      end
+
+      # Get recognition results
+      # @param call_id [String] The unique call ID
+      # @param lang [String] The recognition language
+      # @param return_results [String] The returned result ('words' or 'phrases')
+      # @param alternatives [String] Return alternative results ('0' or '1')
+      # @return [Hash]
+      def get(call_id:, lang: nil, return_results: nil, alternatives: nil)
+        params = { call_id: call_id }
+        params[:lang] = lang if lang
+        params[:return] = return_results if return_results
+        params[:alternatives] = alternatives if alternatives
+        @client.get('/v1/speech_recognition/', params)
+      end
+
+      # Initiate call recognition
+      # @param call_id [String] The unique call ID
+      # @param lang [String] The recognition language
+      # @return [Hash]
+      def initiate(call_id:, lang: nil)
+        params = { call_id: call_id }
+        params[:lang] = lang if lang
+        @client.put('/v1/speech_recognition/', params)
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/resources/statistics.rb b/lib/zadarma/resources/statistics.rb
new file mode 100644
index 0000000..e8bcf2b
--- /dev/null
+++ b/lib/zadarma/resources/statistics.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require 'time'
+
+module Zadarma
+  module Resources
+    # The Statistics resource provides access to call statistics.
+    class Statistics
+      def initialize(client:)
+        @client = client
+      end
+
+      # Get overall call statistics
+      # @param params [Hash] The parameters for the statistics request
+      # @option params [String] :start The start date of the statistics display
+      # @option params [String] :end The end date of the statistics display
+      # @option params [String] :sip Filter based on a specific SIP number
+      # @option params [String] :cost_only Display only the amount of funds spent
+      # @option params [String] :type Request type ('overall' or 'toll-free')
+      # @option params [Integer] :skip Number of lines to be skipped in the sample
+      # @option params [Integer] :limit The limit on the number of input lines
+      # @return [Hash]
+      def statistics(params)
+        response = @client.get('/v1/statistics/', params)
+        response['stats']&.each do |stat|
+          stat['callstart'] = Time.parse(stat['callstart']) if stat['callstart']
+        end
+        response
+      end
+
+      # Get PBX call statistics
+      # @param params [Hash] The parameters for the PBX statistics request
+      # @option params [String] :start The start date of the statistics display
+      # @option params [String] :end The end date of the statistics display
+      # @option params [String] :version Format of the statistics result ('1' or '2')
+      # @option params [Integer] :skip Number of lines to be skipped in the sample
+      # @option params [Integer] :limit The limit on the number of input lines
+      # @option params [String] :call_type Call destination ('in' or 'out')
+      # @return [Hash]
+      def pbx_statistics(params)
+        response = @client.get('/v1/statistics/pbx/', params)
+        response['stats']&.each do |stat|
+          stat['callstart'] = Time.parse(stat['callstart']) if stat['callstart']
+        end
+        response
+      end
+    end
+  end
+end
diff --git a/lib/zadarma/version.rb b/lib/zadarma/version.rb
new file mode 100644
index 0000000..1de4ee1
--- /dev/null
+++ b/lib/zadarma/version.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+module Zadarma
+  VERSION = '2.0.0'
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index a50ef1b..d504b68 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -22,7 +22,7 @@
 # See https://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
 RSpec.configure do |config|
   # rspec-expectations config goes here. You can use an alternate
-  # assertion/expectation library such as wrong or the stdlib/minest
+  # assertion/expectation library such as wrong or the stdlib/minitest
   # assertions if you prefer.
   config.expect_with :rspec do |expectations|
     # This option will default to `true` in RSpec 4. It makes the `description`
diff --git a/spec/zadarma/client_spec.rb b/spec/zadarma/client_spec.rb
new file mode 100644
index 0000000..a11c468
--- /dev/null
+++ b/spec/zadarma/client_spec.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'zadarma'
+
+RSpec.describe Zadarma::Client do
+  let(:api_key) { 'test_key' }
+  let(:api_secret) { 'test_secret' }
+  let(:client) { described_class.new(api_key: api_key, api_secret: api_secret) }
+
+  describe '#initialize' do
+    it 'initializes with an api_key and api_secret' do
+      expect(client).to be_a(described_class)
+    end
+  end
+
+  describe '#get' do
+    it 'makes a GET request to the specified path' do
+      stub_request(:get, 'https://api.zadarma.com/v1/test_path?param=value')
+        .to_return(status: 200, body: '{"status":"success"}', headers: {})
+
+      client.get('/v1/test_path', param: 'value')
+
+      expect(WebMock).to have_requested(:get, 'https://api.zadarma.com/v1/test_path?param=value')
+        .with(headers: { 'Authorization' => /test_key:.*/ }).once
+    end
+  end
+end
diff --git a/spec/zadarma/resources/direct_numbers_spec.rb b/spec/zadarma/resources/direct_numbers_spec.rb
new file mode 100644
index 0000000..164d327
--- /dev/null
+++ b/spec/zadarma/resources/direct_numbers_spec.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'zadarma'
+
+RSpec.describe Zadarma::Resources::DirectNumbers do
+  subject(:direct_numbers) { described_class.new(client: client) }
+
+  let(:client) { Zadarma::Client.new(api_key: 'test_key', api_secret: 'test_secret') }
+
+  describe '#all' do
+    it 'returns the list of direct numbers' do
+      stub_request(:get, 'https://api.zadarma.com/v1/direct_numbers/')
+        .to_return(status: 200, body: '{"info": [{"number": "1234567890"}]}', headers: {})
+      expect(direct_numbers.all).to eq('info' => [{ 'number' => '1234567890' }])
+    end
+  end
+
+  describe '#countries' do
+    it 'returns the list of countries' do
+      stub_request(:get, %r{api.zadarma.com/v1/direct_numbers/countries/})
+        .to_return(body: { status: 'success', info: [] }.to_json)
+
+      response = direct_numbers.countries
+      expect(response['status']).to eq('success')
+    end
+  end
+
+  describe '#country' do
+    it 'returns the list of destinations in a country' do
+      stub_request(:get, %r{api.zadarma.com/v1/direct_numbers/country/})
+        .to_return(body: { status: 'success', info: [] }.to_json)
+
+      response = direct_numbers.country(country: 'US')
+      expect(response['status']).to eq('success')
+    end
+  end
+
+  describe '#available' do
+    it 'returns the list of available numbers' do
+      stub_request(:get, %r{api.zadarma.com/v1/direct_numbers/available/123/})
+        .to_return(body: { status: 'success', numbers: [] }.to_json)
+
+      response = direct_numbers.available(direction_id: '123')
+      expect(response['status']).to eq('success')
+    end
+  end
+
+  describe '#order' do
+    it 'orders a new direct number' do
+      stub_request(:post, %r{api.zadarma.com/v1/direct_numbers/order/})
+        .to_return(body: { status: 'success', number: '1234567890' }.to_json)
+
+      response = direct_numbers.order(direction_id: '123')
+      expect(response).to eq('status' => 'success', 'number' => '1234567890')
+    end
+  end
+
+  describe '#prolong' do
+    it 'prolongs a direct number' do
+      stub_request(:post, %r{api.zadarma.com/v1/direct_numbers/prolong/})
+        .to_return(body: { status: 'success' }.to_json)
+
+      response = direct_numbers.prolong(number: '1234567890', months: 1)
+      expect(response['status']).to eq('success')
+    end
+  end
+end
diff --git a/spec/zadarma/resources/groups_of_documents_spec.rb b/spec/zadarma/resources/groups_of_documents_spec.rb
new file mode 100644
index 0000000..7bb42b7
--- /dev/null
+++ b/spec/zadarma/resources/groups_of_documents_spec.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+require 'zadarma/client'
+require 'webmock/rspec'
+
+RSpec.describe Zadarma::Resources::GroupsOfDocuments do
+  let(:client) { Zadarma::Client.new(api_key: 'test_key', api_secret: 'test_secret') }
+
+  describe '#files' do
+    it 'retrieves the list of files in a group of documents' do
+      stub_request(:get, %r{api.zadarma.com/v1/documents/files/})
+        .to_return(body: { status: 'success' }.to_json)
+
+      response = client.document_files
+      expect(response['status']).to eq('success')
+    end
+  end
+
+  describe '#list' do
+    it 'retrieves the list of groups of documents' do
+      stub_request(:get, %r{api.zadarma.com/v1/documents/groups/list/})
+        .to_return(body: { status: 'success' }.to_json)
+
+      response = client.document_groups
+      expect(response['status']).to eq('success')
+    end
+  end
+
+  describe '#get' do
+    it 'retrieves a group of documents' do
+      stub_request(:get, %r{api.zadarma.com/v1/documents/groups/get/123/})
+        .to_return(body: { status: 'success' }.to_json)
+
+      response = client.get_document_group(id: '123')
+      expect(response['status']).to eq('success')
+    end
+  end
+
+  describe '#create' do
+    it 'creates a new group of documents' do
+      stub_request(:post, %r{api.zadarma.com/v1/documents/groups/create/})
+        .to_return(body: { status: 'success' }.to_json)
+
+      response = client.create_document_group(params: { first_name: 'John', last_name: 'Doe' })
+      expect(response['status']).to eq('success')
+    end
+  end
+
+  describe '#update' do
+    it 'updates a group of documents' do
+      stub_request(:put, %r{api.zadarma.com/v1/documents/groups/update/123/})
+        .to_return(body: { status: 'success' }.to_json)
+
+      response = client.update_document_group(id: '123', params: { first_name: 'Jane' })
+      expect(response['status']).to eq('success')
+    end
+  end
+end
diff --git a/spec/zadarma/resources/info_spec.rb b/spec/zadarma/resources/info_spec.rb
new file mode 100644
index 0000000..c02f616
--- /dev/null
+++ b/spec/zadarma/resources/info_spec.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'zadarma'
+
+RSpec.describe Zadarma::Resources::Info do
+  subject(:info) { described_class.new(client: client) }
+
+  let(:client) { Zadarma::Client.new(api_key: 'test_key', api_secret: 'test_secret') }
+
+  describe '#balance' do
+    it 'returns the current balance' do
+      stub_request(:get, 'https://api.zadarma.com/v1/info/balance/')
+        .to_return(status: 200, body: '{"balance": 100.0}', headers: {})
+      expect(info.balance).to eq('balance' => 100.0)
+    end
+  end
+
+  describe '#price' do
+    it 'returns the price for a given number' do
+      stub_request(:get, 'https://api.zadarma.com/v1/info/price/?number=1234567890')
+        .to_return(status: 200, body: '{"price": 0.01}', headers: {})
+      expect(info.price(number: '1234567890')).to eq('price' => 0.01)
+    end
+
+    it 'returns the price for a given number and caller_id' do
+      stub_request(:get, 'https://api.zadarma.com/v1/info/price/?caller_id=0987654321&number=1234567890')
+        .to_return(status: 200, body: '{"price": 0.02}', headers: {})
+      expect(info.price(number: '1234567890', caller_id: '0987654321')).to eq('price' => 0.02)
+    end
+  end
+end
diff --git a/spec/zadarma/resources/pbx_spec.rb b/spec/zadarma/resources/pbx_spec.rb
new file mode 100644
index 0000000..1c10061
--- /dev/null
+++ b/spec/zadarma/resources/pbx_spec.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'zadarma'
+
+RSpec.describe Zadarma::Resources::Pbx do
+  subject(:pbx) { described_class.new(client: client) }
+
+  let(:client) { Zadarma::Client.new(api_key: 'test_key', api_secret: 'test_secret') }
+
+  describe '#internal' do
+    it 'returns the list of internal numbers' do
+      stub_request(:get, 'https://api.zadarma.com/v1/pbx/internal/')
+        .to_return(status: 200, body: '{"numbers": ["100", "101"]}', headers: {})
+      expect(pbx.internal).to eq('numbers' => %w[100 101])
+    end
+  end
+
+  describe '#set_call_recording' do
+    it 'sets the call recording for a pbx' do
+      stub_request(:put, 'https://api.zadarma.com/v1/pbx/internal/recording/')
+        .to_return(status: 200, body: '{"status": "success"}', headers: {})
+      expect(pbx.set_call_recording(id: '1234', status: 'on')).to eq('status' => 'success')
+    end
+  end
+
+  describe '#pbx_record_request' do
+    it 'requests a call recording' do
+      stub_request(:get, %r{api.zadarma.com/v1/pbx/record/request/})
+        .to_return(body: { status: 'success', link: 'http://example.com/record.mp3' }.to_json)
+
+      response = pbx.pbx_record_request(call_id: '12345')
+      expect(response).to eq('status' => 'success', 'link' => 'http://example.com/record.mp3')
+    end
+  end
+end
diff --git a/spec/zadarma/resources/request_spec.rb b/spec/zadarma/resources/request_spec.rb
new file mode 100644
index 0000000..7b8d2b7
--- /dev/null
+++ b/spec/zadarma/resources/request_spec.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'zadarma'
+
+RSpec.describe Zadarma::Resources::Request do
+  subject(:request) { described_class.new(client: client) }
+
+  let(:client) { Zadarma::Client.new(api_key: 'test_key', api_secret: 'test_secret') }
+
+  describe '#callback' do
+    it 'requests a callback' do
+      stub_request(:get, 'https://api.zadarma.com/v1/request/callback/?from=1234567890&to=0987654321')
+        .to_return(status: 200, body: '{"status": "success"}', headers: {})
+      expect(request.callback(from: '1234567890', to: '0987654321')).to eq('status' => 'success')
+    end
+  end
+end
diff --git a/spec/zadarma/resources/sip_spec.rb b/spec/zadarma/resources/sip_spec.rb
new file mode 100644
index 0000000..d1e688e
--- /dev/null
+++ b/spec/zadarma/resources/sip_spec.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'zadarma'
+
+RSpec.describe Zadarma::Resources::Sip do
+  subject(:sip) { described_class.new(client: client) }
+
+  let(:client) { Zadarma::Client.new(api_key: 'test_key', api_secret: 'test_secret') }
+
+  describe '#all' do
+    it 'returns the list of sips' do
+      stub_request(:get, 'https://api.zadarma.com/v1/sip/')
+        .to_return(status: 200, body: '{"sips": [{"id": "1234"}]}', headers: {})
+      expect(sip.all).to eq('sips' => [{ 'id' => '1234' }])
+    end
+  end
+
+  describe '#set_caller_id' do
+    it 'sets the caller id for a sip' do
+      stub_request(:put, 'https://api.zadarma.com/v1/sip/callerid/')
+        .to_return(status: 200, body: '{"status": "success"}', headers: {})
+      expect(sip.set_caller_id(id: '1234', number: '5678')).to eq('status' => 'success')
+    end
+  end
+
+  describe '#redirection' do
+    it 'returns the redirection status for all sips' do
+      stub_request(:get, 'https://api.zadarma.com/v1/sip/redirection/')
+        .to_return(status: 200, body: '{"info": "test"}', headers: {})
+      expect(sip.redirection).to eq('info' => 'test')
+    end
+
+    it 'returns the redirection status for a specific sip' do
+      stub_request(:get, 'https://api.zadarma.com/v1/sip/redirection/?id=1234')
+        .to_return(status: 200, body: '{"info": "test"}', headers: {})
+      expect(sip.redirection(id: '1234')).to eq('info' => 'test')
+    end
+  end
+
+  describe '#set_redirection' do
+    it 'sets the redirection for a sip' do
+      stub_request(:put, 'https://api.zadarma.com/v1/sip/redirection/')
+        .to_return(status: 200, body: '{"status": "success"}', headers: {})
+      expect(sip.set_redirection(id: '1234', status: 'on')).to eq('status' => 'success')
+    end
+  end
+
+  describe '#status' do
+    it 'returns the status of a sip' do
+      stub_request(:get, %r{api.zadarma.com/v1/sip/123/status/})
+        .to_return(body: { status: 'success', is_online: true }.to_json)
+
+      response = sip.status(sip: '123')
+      expect(response).to eq('status' => 'success', 'is_online' => true)
+    end
+  end
+
+  describe '#create' do
+    it 'creates a new sip' do
+      stub_request(:post, %r{api.zadarma.com/v1/sip/create/})
+        .to_return(body: { status: 'success', sip: '12345' }.to_json)
+
+      response = sip.create(name: 'New SIP')
+      expect(response).to eq('status' => 'success', 'sip' => '12345')
+    end
+  end
+
+  describe '#password' do
+    it 'sets the password for a sip' do
+      stub_request(:put, %r{api.zadarma.com/v1/sip/123/password/})
+        .to_return(body: { status: 'success' }.to_json)
+
+      response = sip.password(sip: '123', value: 'new_password')
+      expect(response['status']).to eq('success')
+    end
+  end
+end
diff --git a/spec/zadarma/resources/sms_spec.rb b/spec/zadarma/resources/sms_spec.rb
new file mode 100644
index 0000000..0d8d1cf
--- /dev/null
+++ b/spec/zadarma/resources/sms_spec.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'zadarma'
+
+RSpec.describe Zadarma::Resources::Sms do
+  subject(:sms) { described_class.new(client: client) }
+
+  let(:client) { Zadarma::Client.new(api_key: 'test_key', api_secret: 'test_secret') }
+
+  describe '#send_sms' do
+    it 'sends an sms' do
+      stub_request(:post, 'https://api.zadarma.com/v1/sms/send/')
+        .to_return(status: 200, body: '{"status": "success"}', headers: {})
+      expect(sms.send_sms(number: '1234567890', message: 'test message')).to eq('status' => 'success')
+    end
+  end
+end
diff --git a/spec/zadarma/resources/speech_recognition_spec.rb b/spec/zadarma/resources/speech_recognition_spec.rb
new file mode 100644
index 0000000..1e43a8e
--- /dev/null
+++ b/spec/zadarma/resources/speech_recognition_spec.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require 'zadarma/client'
+require 'webmock/rspec'
+
+RSpec.describe Zadarma::Resources::SpeechRecognition do
+  let(:client) { Zadarma::Client.new(api_key: 'test_key', api_secret: 'test_secret') }
+
+  describe '#get' do
+    it 'retrieves speech recognition results' do
+      stub_request(:get, %r{api.zadarma.com/v1/speech_recognition/})
+        .to_return(body: { status: 'success' }.to_json)
+
+      response = client.get_speech_recognition(call_id: '12345')
+      expect(response['status']).to eq('success')
+    end
+  end
+
+  describe '#initiate' do
+    it 'initiates speech recognition' do
+      stub_request(:put, %r{api.zadarma.com/v1/speech_recognition/})
+        .to_return(body: { status: 'success' }.to_json)
+
+      response = client.initiate_speech_recognition(call_id: '12345')
+      expect(response['status']).to eq('success')
+    end
+  end
+end
diff --git a/spec/zadarma/resources/statistics_spec.rb b/spec/zadarma/resources/statistics_spec.rb
new file mode 100644
index 0000000..1e9b9bd
--- /dev/null
+++ b/spec/zadarma/resources/statistics_spec.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require 'zadarma/client'
+require 'webmock/rspec'
+
+RSpec.describe Zadarma::Resources::Statistics do
+  let(:client) { Zadarma::Client.new(api_key: 'test_key', api_secret: 'test_secret') }
+
+  describe '#statistics' do
+    it 'retrieves statistics' do
+      stub_request(:get, %r{api.zadarma.com/v1/statistics/})
+        .to_return(body: { status: 'success', stats: [] }.to_json)
+
+      response = client.statistics(start: '2023-01-01', end: '2023-01-31')
+      expect(response['status']).to eq('success')
+    end
+  end
+
+  describe '#pbx_statistics' do
+    it 'retrieves pbx statistics' do
+      stub_request(:get, %r{api.zadarma.com/v1/statistics/pbx/})
+        .to_return(body: { status: 'success', stats: [] }.to_json)
+
+      response = client.pbx_statistics(start: '2023-01-01', end: '2023-01-31')
+      expect(response['status']).to eq('success')
+    end
+  end
+end