diff --git a/README.md b/README.md
index 7066ec93..19fe1b7e 100644
--- a/README.md
+++ b/README.md
@@ -84,49 +84,22 @@ Usage: i18n-tasks add-missing [options] [locale ...]
     -h, --help     Display this help message.
 ```
 
-### Google Translate missing keys
+### Translate Missing Keys
 
-Translate missing values with Google Translate ([more below on the API key](#google-translation-config)).
+Translate missing keys using a backend service of your choice.
 
 ```console
 $ i18n-tasks translate-missing
 
-# accepts from and locales options:
-$ i18n-tasks translate-missing --from=base es fr
+# accepts backend, from and locales options
+$ i18n-tasks translate-missing --from=base es fr --backend=google
 ```
 
-### DeepL Pro Translate missing keys
-
-Translate missing values with DeepL Pro Translate ([more below on the API key](#deepl-translation-config)).
-
-```console
-$ i18n-tasks translate-missing --backend=deepl
-
-# accepts from and locales options:
-$ i18n-tasks translate-missing --backend=deepl --from=en fr nl
-```
-
-### Yandex Translate missing keys
-
-Translate missing values with Yandex Translate ([more below on the API key](#yandex-translation-config)).
-
-```console
-$ i18n-tasks translate-missing --backend=yandex
-
-# accepts from and locales options:
-$ i18n-tasks translate-missing --from=en es fr
-```
-
-### OpenAI Translate missing keys
-
-Translate missing values with OpenAI ([more below on the API key](#openai-translation-config)).
-
-```console
-$ i18n-tasks translate-missing --backend=openai
-
-# accepts from and locales options:
-$ i18n-tasks translate-missing --from=en es fr
-```
+Available backends:
+- `google` - [Google Translate](#google-translation-config)
+- `deepl` - [DeepL Pro](#deepl-translation-config)
+- `yandex` - [Yandex Translate](#yandex-translation-config)
+- `openai` - [OpenAI](#openai-translation-config)
 
 ### Find usages
 
@@ -435,6 +408,7 @@ Put the key in `GOOGLE_TRANSLATE_API_KEY` environment variable or in the config
 ```yaml
 # config/i18n-tasks.yml
 translation:
+  backend: google
   google_translate_api_key: <Google Translate API key>
 ```
 
@@ -452,6 +426,7 @@ GOOGLE_TRANSLATE_API_KEY=<Google Translate API key>
 ```yaml
 # config/i18n-tasks.yml
 translation:
+  backend: deepl
   deepl_api_key: <DeepL Pro API key>
   deepl_host: <optional>
   deepl_version: <optional>
@@ -478,6 +453,7 @@ DEEPL_VERSION=<optional>
 ```yaml
 # config/i18n-tasks.yml
 translation:
+  backend: yandex
   yandex_api_key: <Yandex API key>
 ```
 
@@ -495,6 +471,7 @@ YANDEX_API_KEY=<Yandex API key>
 ```yaml
 # config/i18n-tasks.yml
 translation:
+  backend: openai
   openai_api_key: <OpenAI API key>
   openai_model: <optional>
 ```
diff --git a/config/locales/en.yml b/config/locales/en.yml
index c335c8d3..2e72475a 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -26,7 +26,7 @@ en:
           strict: >-
             Avoid inferring dynamic key usages such as t("cats.#{cat}.name"). Takes precedence over
             the config setting if set.
-          translation_backend: Translation backend (google or deepl)
+          translation_backend: Translation backend [google, deepl, yandex, openai])
           value: >-
             Value. Interpolates: %%{value}, %%{human_key}, %%{key}, %%{default}, %%{value_or_human_key},
             %%{value_or_default_or_human_key}
@@ -69,6 +69,7 @@ en:
       enum_opt:
         invalid: "%{invalid} is not one of: %{valid}."
       errors:
+        invalid_backend: 'Invalid backend: %{invalid}. Must be one of %{valid}.'
         invalid_format: 'invalid format: %{invalid}. valid: %{valid}.'
         invalid_locale: 'invalid locale: %{invalid}'
         invalid_missing_type:
diff --git a/config/locales/ru.yml b/config/locales/ru.yml
index eda1246b..c6e7e4b2 100644
--- a/config/locales/ru.yml
+++ b/config/locales/ru.yml
@@ -23,7 +23,7 @@ ru:
           out_format: 'Формат вывода: %{valid_text}.'
           pattern_router: 'Использовать pattern_router: ключи распределятся по файлам согласно data.write'
           strict: Не угадывать динамические использования ключей, например `t("category.#{category.key}")`
-          translation_backend: Движок перевода (google или deepl)
+          translation_backend: Движок перевода [google, deepl, yandex, openai]
           value: >-
             Значение, интерполируется с %%{value}, %%{human_key}, %%{key}, %%{default}, %%{value_or_human_key},
             %%{value_or_default_or_human_key}
@@ -66,6 +66,7 @@ ru:
       enum_opt:
         invalid: "%{invalid} не является одним из: %{valid}."
       errors:
+        invalid_backend: 'Недопустимый источник данных: %{invalid}. Должен быть одним из %{valid}.'
         invalid_format: 'Неизвестный формат %{invalid}. Форматы: %{valid}.'
         invalid_locale: Неверный язык %{invalid}
         invalid_missing_type:
diff --git a/lib/i18n/tasks/command/commands/missing.rb b/lib/i18n/tasks/command/commands/missing.rb
index 84e348e1..06883a83 100644
--- a/lib/i18n/tasks/command/commands/missing.rb
+++ b/lib/i18n/tasks/command/commands/missing.rb
@@ -48,7 +48,9 @@ def translate_missing(opt = {})
             pattern_re = i18n.compile_key_pattern(opt[:pattern])
             missing.select_keys! { |full_key, _node| full_key =~ pattern_re }
           end
-          translated = i18n.translate_forest missing, from: opt[:from], backend: opt[:backend].to_sym
+
+          backend = opt[:backend].presence || i18n.translation_config[:backend]
+          translated = i18n.translate_forest missing, from: opt[:from], backend: backend.to_sym
           i18n.data.merge! translated
           log_stderr t('i18n_tasks.translate_missing.translated', count: translated.leaves.count)
           print_forest translated, opt
diff --git a/lib/i18n/tasks/command/option_parsers/enum.rb b/lib/i18n/tasks/command/option_parsers/enum.rb
index e476d247..8bd1577e 100644
--- a/lib/i18n/tasks/command/option_parsers/enum.rb
+++ b/lib/i18n/tasks/command/option_parsers/enum.rb
@@ -9,17 +9,18 @@ class Parser
             I18n.t('i18n_tasks.cmd.enum_opt.invalid', invalid: invalid, valid: valid * ', ')
           end
 
-          def initialize(valid, error_message = DEFAULT_ERROR)
+          def initialize(valid, error_message = DEFAULT_ERROR, allow_blank: false)
             @valid         = valid.map(&:to_s)
             @error_message = error_message
+            @allow_blank   = allow_blank
           end
 
           def call(value, *)
-            return @valid.first unless value.present?
+            return @valid.first if value.blank? && !@allow_blank
 
             if @valid.include?(value)
               value
-            else
+            elsif value.present? || !@allow_blank
               fail CommandError, @error_message.call(value, @valid)
             end
           end
diff --git a/lib/i18n/tasks/command/options/locales.rb b/lib/i18n/tasks/command/options/locales.rb
index 46becad5..1d06127e 100644
--- a/lib/i18n/tasks/command/options/locales.rb
+++ b/lib/i18n/tasks/command/options/locales.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'i18n/tasks/command/option_parsers/locale'
+require 'i18n/tasks/command/option_parsers/enum'
 
 module I18n::Tasks
   module Command
@@ -31,13 +32,21 @@ module Locales
             parser: OptionParsers::Locale::Parser,
             default: 'base'
 
-        TRANSLATION_BACKENDS = %w[google deepl].freeze
+        TRANSLATION_BACKENDS = %w[google deepl yandex openai].freeze
         arg :translation_backend,
             '-b',
             '--backend BACKEND',
             t('i18n_tasks.cmd.args.desc.translation_backend'),
-            parser: OptionParsers::Locale::Parser,
-            default: TRANSLATION_BACKENDS[0]
+            parser:
+              OptionParsers::Enum::Parser.new(
+                TRANSLATION_BACKENDS,
+                proc do |value, valid|
+                  if value.present?
+                    I18n.t('i18n_tasks.cmd.errors.invalid_backend', invalid: value&.strip, valid: valid * ', ')
+                  end
+                end,
+                allow_blank: true
+              )
       end
     end
   end
diff --git a/lib/i18n/tasks/configuration.rb b/lib/i18n/tasks/configuration.rb
index 4463e382..1bc3c4a4 100644
--- a/lib/i18n/tasks/configuration.rb
+++ b/lib/i18n/tasks/configuration.rb
@@ -5,7 +5,8 @@ module I18n::Tasks::Configuration # rubocop:disable Metrics/ModuleLength
     base_locale: 'en',
     internal_locale: 'en',
     search: ::I18n::Tasks::UsedKeys::SEARCH_DEFAULTS,
-    data: ::I18n::Tasks::Data::DATA_DEFAULTS
+    data: ::I18n::Tasks::Data::DATA_DEFAULTS,
+    translation_backend: :google
   }.freeze
 
   # i18n-tasks config (defaults + config/i18n-tasks.yml)
@@ -59,9 +60,10 @@ def data_config
 
   # translation config
   # @return [Hash{String => String,Hash,Array}]
-  def translation_config
+  def translation_config # rubocop:disable Metrics/AbcSize
     @config_sections[:translation] ||= begin
       conf = (config[:translation] || {}).with_indifferent_access
+      conf[:backend] ||= DEFAULTS[:translation_backend]
       conf[:google_translate_api_key] = ENV['GOOGLE_TRANSLATE_API_KEY'] if ENV.key?('GOOGLE_TRANSLATE_API_KEY')
       conf[:deepl_api_key] = ENV['DEEPL_AUTH_KEY'] if ENV.key?('DEEPL_AUTH_KEY')
       conf[:deepl_host] = ENV['DEEPL_HOST'] if ENV.key?('DEEPL_HOST')
diff --git a/lib/i18n/tasks/translation.rb b/lib/i18n/tasks/translation.rb
index 31edfdf5..b73bfcba 100644
--- a/lib/i18n/tasks/translation.rb
+++ b/lib/i18n/tasks/translation.rb
@@ -11,7 +11,7 @@ module Translation
     # @param [String] from locale
     # @param [:deepl, :openai, :google, :yandex] backend
     # @return [I18n::Tasks::Tree::Siblings] translated forest
-    def translate_forest(forest, from:, backend: :google)
+    def translate_forest(forest, from:, backend:)
       case backend
       when :deepl
         Translators::DeeplTranslator.new(self).translate_forest(forest, from)
diff --git a/spec/commands/missing_commands_spec.rb b/spec/commands/missing_commands_spec.rb
index 4411d747..973abb5d 100644
--- a/spec/commands/missing_commands_spec.rb
+++ b/spec/commands/missing_commands_spec.rb
@@ -6,10 +6,11 @@
   delegate :run_cmd, to: :TestCodebase
 
   let(:missing_keys) { { 'a' => 'A', 'ref' => :ref } }
+  let(:config) { { base_locale: 'en', locales: %w[es fr] } }
 
   around do |ex|
     TestCodebase.setup(
-      'config/i18n-tasks.yml' => { base_locale: 'en', locales: %w[es fr] }.to_yaml,
+      'config/i18n-tasks.yml' => config.to_yaml,
       'config/locales/es.yml' => { 'es' => missing_keys }.to_yaml
     )
     TestCodebase.in_test_app_dir { ex.call }
@@ -47,4 +48,40 @@
       end
     end
   end
+
+  describe '#translate_missing' do
+    it 'defaults the backend to google when not specified' do
+      google_double = instance_double(I18n::Tasks::Translators::GoogleTranslator)
+      allow(I18n::Tasks::Translators::GoogleTranslator).to receive(:new).and_return(google_double)
+      allow(google_double).to receive(:translate_forest).and_return(I18n::Tasks::BaseTask.new.empty_forest)
+      expect(google_double).to receive(:translate_forest)
+
+      run_cmd 'translate-missing'
+    end
+
+    it 'errors when invalid backend is specified' do
+      invalid = 'awesome-translate'
+
+      expect { run_cmd 'translate-missing', "-b #{invalid}" }.to(
+        raise_error(
+          I18n::Tasks::CommandError,
+          I18n.t('i18n_tasks.cmd.errors.invalid_backend',
+                 invalid: invalid, valid: I18n::Tasks::Command::Options::Locales::TRANSLATION_BACKENDS * ', ')
+        )
+      )
+    end
+
+    context 'when backend is specified in config' do
+      let(:config) { { base_locale: 'en', locales: %w[es fr], translation: { backend: 'deepl' } } }
+
+      it 'uses the backend from the configuration' do
+        deepl_double = instance_double(I18n::Tasks::Translators::DeeplTranslator)
+        allow(I18n::Tasks::Translators::DeeplTranslator).to receive(:new).and_return(deepl_double)
+        allow(deepl_double).to receive(:translate_forest).and_return(I18n::Tasks::BaseTask.new.empty_forest)
+        expect(deepl_double).to receive(:translate_forest)
+
+        run_cmd 'translate-missing'
+      end
+    end
+  end
 end