diff --git a/app/models/ci/trigger_request.rb b/app/models/ci/trigger_request.rb
index c58ce5c3717a60056da48879ba155815f91e33ae..2c8605982818be3f3f11d14986bac5a8df9c7d5a 100644
--- a/app/models/ci/trigger_request.rb
+++ b/app/models/ci/trigger_request.rb
@@ -6,6 +6,10 @@ module Ci
     belongs_to :pipeline, foreign_key: :commit_id
     has_many :builds
 
+    # We switched to Ci::PipelineVariable from Ci::TriggerRequest.variables.
+    # Ci::TriggerRequest doesn't save variables anymore.
+    validates :variables, absence: true
+
     serialize :variables # rubocop:disable Cop/ActiveRecordSerialize
 
     def user_variables
diff --git a/app/presenters/ci/build_presenter.rb b/app/presenters/ci/build_presenter.rb
index c495c3f39bb0e012d5da2c110762d39336f4ac1b..255475e1fe65d4b8e402d03a7617af2423d789aa 100644
--- a/app/presenters/ci/build_presenter.rb
+++ b/app/presenters/ci/build_presenter.rb
@@ -17,5 +17,16 @@ module Ci
         "Job is redundant and is auto-canceled by Pipeline ##{auto_canceled_by_id}"
       end
     end
+
+    def trigger_variables
+      return [] unless trigger_request
+
+      @trigger_variables ||=
+        if pipeline.variables.any?
+          pipeline.variables.map(&:to_runner_variable)
+        else
+          trigger_request.user_variables
+        end
+    end
   end
 end
diff --git a/app/services/ci/create_trigger_request_service.rb b/app/services/ci/create_trigger_request_service.rb
deleted file mode 100644
index b2aa457bbd569ca10210f21bce8670d03204b601..0000000000000000000000000000000000000000
--- a/app/services/ci/create_trigger_request_service.rb
+++ /dev/null
@@ -1,19 +0,0 @@
-# This class is deprecated because we're closing Ci::TriggerRequest.
-# New class is PipelineTriggerService (app/services/ci/pipeline_trigger_service.rb)
-# which is integrated with Ci::PipelineVariable instaed of Ci::TriggerRequest.
-# We remove this class after we removed v1 and v3 API. This class is still being
-# referred by such legacy code.
-module Ci
-  module CreateTriggerRequestService
-    Result = Struct.new(:trigger_request, :pipeline)
-
-    def self.execute(project, trigger, ref, variables = nil)
-      trigger_request = trigger.trigger_requests.create(variables: variables)
-
-      pipeline = Ci::CreatePipelineService.new(project, trigger.owner, ref: ref)
-        .execute(:trigger, ignore_skip_ci: true, trigger_request: trigger_request)
-
-      Result.new(trigger_request, pipeline)
-    end
-  end
-end
diff --git a/app/views/projects/jobs/_sidebar.html.haml b/app/views/projects/jobs/_sidebar.html.haml
index f5d5bc7eda988490ba559f4fec8f673397767529..43e23bb2200951d95c5c6d648180d47c62cf0e92 100644
--- a/app/views/projects/jobs/_sidebar.html.haml
+++ b/app/views/projects/jobs/_sidebar.html.haml
@@ -46,14 +46,14 @@
             %span.build-light-text Token:
             #{@build.trigger_request.trigger.short_token}
 
-          - if @build.trigger_request.variables
+          - if @build.trigger_variables.any?
             %p
               %button.btn.group.btn-group-justified.reveal-variables Reveal Variables
 
             %dl.js-build-variables.trigger-build-variables.hide
-              - @build.trigger_request.variables.each do |key, value|
-                %dt.js-build-variable.trigger-build-variable= key
-                %dd.js-build-value.trigger-build-value= value
+              - @build.trigger_variables.each do |trigger_variable|
+                %dt.js-build-variable.trigger-build-variable= trigger_variable[:key]
+                %dd.js-build-value.trigger-build-value= trigger_variable[:value]
 
       %div{ class: (@build.pipeline.stages_count > 1 ? "block" : "block-last") }
         %p
diff --git a/lib/api/v3/triggers.rb b/lib/api/v3/triggers.rb
index e9d4c35307bbea624de51d1e62368f18511327fe..534911fde5c8cdbb833acbc6852e3d709717a38f 100644
--- a/lib/api/v3/triggers.rb
+++ b/lib/api/v3/triggers.rb
@@ -16,25 +16,31 @@ module API
           optional :variables, type: Hash, desc: 'The list of variables to be injected into build'
         end
         post ":id/(ref/:ref/)trigger/builds", requirements: { ref: /.+/ } do
-          project = find_project(params[:id])
-          trigger = Ci::Trigger.find_by_token(params[:token].to_s)
-          not_found! unless project && trigger
-          unauthorized! unless trigger.project == project
-
           # validate variables
-          variables = params[:variables].to_h
-          unless variables.all? { |key, value| key.is_a?(String) && value.is_a?(String) }
+          params[:variables] = params[:variables].to_h
+          unless params[:variables].all? { |key, value| key.is_a?(String) && value.is_a?(String) }
             render_api_error!('variables needs to be a map of key-valued strings', 400)
           end
 
-          # create request and trigger builds
-          result = Ci::CreateTriggerRequestService.execute(project, trigger, params[:ref].to_s, variables)
-          pipeline = result.pipeline
+          project = find_project(params[:id])
+          not_found! unless project
+
+          result = Ci::PipelineTriggerService.new(project, nil, params).execute
+          not_found! unless result
 
-          if pipeline.persisted?
-            present result.trigger_request, with: ::API::V3::Entities::TriggerRequest
+          if result[:http_status]
+            render_api_error!(result[:message], result[:http_status])
           else
-            render_validation_error!(pipeline)
+            pipeline = result[:pipeline]
+
+            # We switched to Ci::PipelineVariable from Ci::TriggerRequest.variables.
+            # Ci::TriggerRequest doesn't save variables anymore.
+            # Here is copying Ci::PipelineVariable to Ci::TriggerRequest.variables for presenting the variables.
+            # The same endpoint in v4 API pressents Pipeline instead of TriggerRequest, so it doesn't need such a process.
+            trigger_request = pipeline.trigger_requests.last
+            trigger_request.variables = params[:variables]
+
+            present trigger_request, with: ::API::V3::Entities::TriggerRequest
           end
         end
 
diff --git a/spec/factories/ci/builds.rb b/spec/factories/ci/builds.rb
index 25ec63de94afc29f2437ea28fdcc910741f3740a..c2b59239af9bae352b38a66ff861f82ee0a2f0ca 100644
--- a/spec/factories/ci/builds.rb
+++ b/spec/factories/ci/builds.rb
@@ -107,7 +107,7 @@ FactoryGirl.define do
     end
 
     trait :triggered do
-      trigger_request factory: :ci_trigger_request_with_variables
+      trigger_request factory: :ci_trigger_request
     end
 
     after(:build) do |build, evaluator|
diff --git a/spec/factories/ci/pipeline_variable_variables.rb b/spec/factories/ci/pipeline_variables.rb
similarity index 100%
rename from spec/factories/ci/pipeline_variable_variables.rb
rename to spec/factories/ci/pipeline_variables.rb
diff --git a/spec/factories/ci/trigger_requests.rb b/spec/factories/ci/trigger_requests.rb
index 10e0ab4fd3ce239e5fd9b6994158049d1a259256..40b8848920ef7d40c4a02322f2a9fe840c8c4e68 100644
--- a/spec/factories/ci/trigger_requests.rb
+++ b/spec/factories/ci/trigger_requests.rb
@@ -1,14 +1,5 @@
 FactoryGirl.define do
   factory :ci_trigger_request, class: Ci::TriggerRequest do
     trigger factory: :ci_trigger
-
-    factory :ci_trigger_request_with_variables do
-      variables do
-        {
-          TRIGGER_KEY_1: 'TRIGGER_VALUE_1',
-          TRIGGER_KEY_2: 'TRIGGER_VALUE_2'
-        }
-      end
-    end
   end
 end
diff --git a/spec/features/projects/jobs_spec.rb b/spec/features/projects/jobs_spec.rb
index 037ac00d39f06fd93c7701814497697130bf8488..3b5c696628725772552fc6c0eaf6fba9302cd857 100644
--- a/spec/features/projects/jobs_spec.rb
+++ b/spec/features/projects/jobs_spec.rb
@@ -292,26 +292,44 @@ feature 'Jobs' do
     end
 
     feature 'Variables' do
-      let(:trigger_request) { create(:ci_trigger_request_with_variables) }
+      let(:trigger_request) { create(:ci_trigger_request) }
 
       let(:job) do
         create :ci_build, pipeline: pipeline, trigger_request: trigger_request
       end
 
-      before do
-        visit project_job_path(project, job)
+      shared_examples 'expected variables behavior' do
+        it 'shows variable key and value after click', js: true do
+          expect(page).to have_css('.reveal-variables')
+          expect(page).not_to have_css('.js-build-variable')
+          expect(page).not_to have_css('.js-build-value')
+
+          click_button 'Reveal Variables'
+
+          expect(page).not_to have_css('.reveal-variables')
+          expect(page).to have_selector('.js-build-variable', text: 'TRIGGER_KEY_1')
+          expect(page).to have_selector('.js-build-value', text: 'TRIGGER_VALUE_1')
+        end
       end
 
-      it 'shows variable key and value after click', js: true do
-        expect(page).to have_css('.reveal-variables')
-        expect(page).not_to have_css('.js-build-variable')
-        expect(page).not_to have_css('.js-build-value')
+      context 'when variables are stored in trigger_request' do
+        before do
+          trigger_request.update_attribute(:variables, { 'TRIGGER_KEY_1' => 'TRIGGER_VALUE_1' } )
 
-        click_button 'Reveal Variables'
+          visit project_job_path(project, job)
+        end
+
+        it_behaves_like 'expected variables behavior'
+      end
+
+      context 'when variables are stored in pipeline_variables' do
+        before do
+          create(:ci_pipeline_variable, pipeline: pipeline, key: 'TRIGGER_KEY_1', value: 'TRIGGER_VALUE_1')
+
+          visit project_job_path(project, job)
+        end
 
-        expect(page).not_to have_css('.reveal-variables')
-        expect(page).to have_selector('.js-build-variable', text: 'TRIGGER_KEY_1')
-        expect(page).to have_selector('.js-build-value', text: 'TRIGGER_VALUE_1')
+        it_behaves_like 'expected variables behavior'
       end
     end
 
diff --git a/spec/models/ci/build_spec.rb b/spec/models/ci/build_spec.rb
index 3fe3ec17d3695a8f6a3505a1468b3674ae6b13c5..08d22f166e4314c4f07e534daa1b6320e459f62e 100644
--- a/spec/models/ci/build_spec.rb
+++ b/spec/models/ci/build_spec.rb
@@ -1492,10 +1492,12 @@ describe Ci::Build do
 
     context 'when build is for triggers' do
       let(:trigger) { create(:ci_trigger, project: project) }
-      let(:trigger_request) { create(:ci_trigger_request_with_variables, pipeline: pipeline, trigger: trigger) }
+      let(:trigger_request) { create(:ci_trigger_request, pipeline: pipeline, trigger: trigger) }
+
       let(:user_trigger_variable) do
-        { key: :TRIGGER_KEY_1, value: 'TRIGGER_VALUE_1', public: false }
+        { key: 'TRIGGER_KEY_1', value: 'TRIGGER_VALUE_1', public: false }
       end
+
       let(:predefined_trigger_variable) do
         { key: 'CI_PIPELINE_TRIGGERED', value: 'true', public: true }
       end
@@ -1504,8 +1506,26 @@ describe Ci::Build do
         build.trigger_request = trigger_request
       end
 
-      it { is_expected.to include(user_trigger_variable) }
-      it { is_expected.to include(predefined_trigger_variable) }
+      shared_examples 'returns variables for triggers' do
+        it { is_expected.to include(user_trigger_variable) }
+        it { is_expected.to include(predefined_trigger_variable) }
+      end
+
+      context 'when variables are stored in trigger_request' do
+        before do
+          trigger_request.update_attribute(:variables, { 'TRIGGER_KEY_1' => 'TRIGGER_VALUE_1' } )
+        end
+
+        it_behaves_like 'returns variables for triggers'
+      end
+
+      context 'when variables are stored in pipeline_variables' do
+        before do
+          create(:ci_pipeline_variable, pipeline: pipeline, key: 'TRIGGER_KEY_1', value: 'TRIGGER_VALUE_1')
+        end
+
+        it_behaves_like 'returns variables for triggers'
+      end
     end
 
     context 'when pipeline has a variable' do
diff --git a/spec/models/ci/trigger_request_spec.rb b/spec/models/ci/trigger_request_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..7dcf3528f738ac7c01d4530b9f936451c11acd96
--- /dev/null
+++ b/spec/models/ci/trigger_request_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe Ci::TriggerRequest do
+  describe 'validation' do
+    it 'be invalid if saving a variable' do
+      trigger = build(:ci_trigger_request, variables: { TRIGGER_KEY_1: 'TRIGGER_VALUE_1' } )
+
+      expect(trigger).not_to be_valid
+    end
+
+    it 'be valid if not saving a variable' do
+      trigger = build(:ci_trigger_request)
+
+      expect(trigger).to be_valid
+    end
+  end
+end
diff --git a/spec/presenters/ci/build_presenter_spec.rb b/spec/presenters/ci/build_presenter_spec.rb
index a7a34ecac72d4f6bedc67f122ecb7547e49abff7..1a8001be6ab2a93c216a19702c21aeb69d75f121 100644
--- a/spec/presenters/ci/build_presenter_spec.rb
+++ b/spec/presenters/ci/build_presenter_spec.rb
@@ -100,4 +100,38 @@ describe Ci::BuildPresenter do
       end
     end
   end
+
+  describe '#trigger_variables' do
+    let(:build) { create(:ci_build, pipeline: pipeline, trigger_request: trigger_request) }
+    let(:trigger) { create(:ci_trigger, project: project) }
+    let(:trigger_request) { create(:ci_trigger_request, pipeline: pipeline, trigger: trigger) }
+
+    context 'when variable is stored in ci_pipeline_variables' do
+      let!(:pipeline_variable) { create(:ci_pipeline_variable, pipeline: pipeline) }
+
+      context 'when pipeline is triggered by trigger API' do
+        it 'returns variables' do
+          expect(presenter.trigger_variables).to eq([pipeline_variable.to_runner_variable])
+        end
+      end
+
+      context 'when pipeline is not triggered by trigger API' do
+        let(:build) { create(:ci_build, pipeline: pipeline) }
+
+        it 'does not return variables' do
+          expect(presenter.trigger_variables).to eq([])
+        end
+      end
+    end
+
+    context 'when variable is stored in ci_trigger_requests.variables' do
+      before do
+        trigger_request.update_attribute(:variables, { 'TRIGGER_KEY_1' => 'TRIGGER_VALUE_1' } )
+      end
+
+      it 'returns variables' do
+        expect(presenter.trigger_variables).to eq(trigger_request.user_variables)
+      end
+    end
+  end
 end
diff --git a/spec/requests/api/runner_spec.rb b/spec/requests/api/runner_spec.rb
index 419a65c69b5f6536f82217dd95f18afd89e8d2c5..12720355a6df959cf2801bb5aa90a3772a964602 100644
--- a/spec/requests/api/runner_spec.rb
+++ b/spec/requests/api/runner_spec.rb
@@ -557,17 +557,36 @@ describe API::Runner do
                { 'key' => 'TRIGGER_KEY_1', 'value' => 'TRIGGER_VALUE_1', 'public' => false }]
             end
 
+            let(:trigger) { create(:ci_trigger, project: project) }
+            let!(:trigger_request) { create(:ci_trigger_request, pipeline: pipeline, builds: [job], trigger: trigger) }
+
             before do
-              trigger = create(:ci_trigger, project: project)
-              create(:ci_trigger_request_with_variables, pipeline: pipeline, builds: [job], trigger: trigger)
               project.variables << Ci::Variable.new(key: 'SECRET_KEY', value: 'secret_value')
             end
 
-            it 'returns variables for triggers' do
-              request_job
+            shared_examples 'expected variables behavior' do
+              it 'returns variables for triggers' do
+                request_job
 
-              expect(response).to have_http_status(201)
-              expect(json_response['variables']).to include(*expected_variables)
+                expect(response).to have_http_status(201)
+                expect(json_response['variables']).to include(*expected_variables)
+              end
+            end
+
+            context 'when variables are stored in trigger_request' do
+              before do
+                trigger_request.update_attribute(:variables, { TRIGGER_KEY_1: 'TRIGGER_VALUE_1' } )
+              end
+
+              it_behaves_like 'expected variables behavior'
+            end
+
+            context 'when variables are stored in pipeline_variables' do
+              before do
+                create(:ci_pipeline_variable, pipeline: pipeline, key: :TRIGGER_KEY_1, value: 'TRIGGER_VALUE_1')
+              end
+
+              it_behaves_like 'expected variables behavior'
             end
           end
 
diff --git a/spec/requests/api/v3/triggers_spec.rb b/spec/requests/api/v3/triggers_spec.rb
index d46481368412d433e8dd77182fb219577f44ed3a..7ccf387f2dc9ca125c745bd2e203e2b455820895 100644
--- a/spec/requests/api/v3/triggers_spec.rb
+++ b/spec/requests/api/v3/triggers_spec.rb
@@ -37,7 +37,7 @@ describe API::V3::Triggers do
 
       it 'returns unauthorized if token is for different project' do
         post v3_api("/projects/#{project2.id}/trigger/builds"), options.merge(ref: 'master')
-        expect(response).to have_http_status(401)
+        expect(response).to have_http_status(404)
       end
     end
 
@@ -80,7 +80,8 @@ describe API::V3::Triggers do
           post v3_api("/projects/#{project.id}/trigger/builds"), options.merge(variables: variables, ref: 'master')
           expect(response).to have_http_status(201)
           pipeline.builds.reload
-          expect(pipeline.builds.first.trigger_request.variables).to eq(variables)
+          expect(pipeline.variables.map { |v| { v.key => v.value } }.first).to eq(variables)
+          expect(json_response['variables']).to eq(variables)
         end
       end
     end
diff --git a/spec/services/ci/create_trigger_request_service_spec.rb b/spec/services/ci/create_trigger_request_service_spec.rb
deleted file mode 100644
index 8295813a1cad7266059d2ed68a594a2afb294cd7..0000000000000000000000000000000000000000
--- a/spec/services/ci/create_trigger_request_service_spec.rb
+++ /dev/null
@@ -1,52 +0,0 @@
-require 'spec_helper'
-
-describe Ci::CreateTriggerRequestService do
-  let(:service) { described_class }
-  let(:project) { create(:project, :repository) }
-  let(:trigger) { create(:ci_trigger, project: project, owner: owner) }
-  let(:owner) { create(:user) }
-
-  before do
-    stub_ci_pipeline_to_return_yaml_file
-
-    project.add_developer(owner)
-  end
-
-  describe '#execute' do
-    context 'valid params' do
-      subject { service.execute(project, trigger, 'master') }
-
-      context 'without owner' do
-        it { expect(subject.trigger_request).to be_kind_of(Ci::TriggerRequest) }
-        it { expect(subject.trigger_request.builds.first).to be_kind_of(Ci::Build) }
-        it { expect(subject.pipeline).to be_kind_of(Ci::Pipeline) }
-        it { expect(subject.pipeline).to be_trigger }
-      end
-
-      context 'with owner' do
-        it { expect(subject.trigger_request).to be_kind_of(Ci::TriggerRequest) }
-        it { expect(subject.trigger_request.builds.first).to be_kind_of(Ci::Build) }
-        it { expect(subject.trigger_request.builds.first.user).to eq(owner) }
-        it { expect(subject.pipeline).to be_kind_of(Ci::Pipeline) }
-        it { expect(subject.pipeline).to be_trigger }
-        it { expect(subject.pipeline.user).to eq(owner) }
-      end
-    end
-
-    context 'no commit for ref' do
-      subject { service.execute(project, trigger, 'other-branch') }
-
-      it { expect(subject.pipeline).not_to be_persisted }
-    end
-
-    context 'no builds created' do
-      subject { service.execute(project, trigger, 'master') }
-
-      before do
-        stub_ci_pipeline_yaml_file('script: { only: [develop], script: hello World }')
-      end
-
-      it { expect(subject.pipeline).not_to be_persisted }
-    end
-  end
-end
diff --git a/spec/views/projects/jobs/show.html.haml_spec.rb b/spec/views/projects/jobs/show.html.haml_spec.rb
index 117f48450e2a78bbcc9b2791836c728f27954b8b..d4279626e75666b5a1522bdbaf54f847e35e46ef 100644
--- a/spec/views/projects/jobs/show.html.haml_spec.rb
+++ b/spec/views/projects/jobs/show.html.haml_spec.rb
@@ -195,20 +195,4 @@ describe 'projects/jobs/show' do
         text: /\A\n#{Regexp.escape(commit_title)}\n\Z/)
     end
   end
-
-  describe 'shows trigger variables in sidebar' do
-    let(:trigger_request) { create(:ci_trigger_request_with_variables, pipeline: pipeline) }
-
-    before do
-      build.trigger_request = trigger_request
-      render
-    end
-
-    it 'shows trigger variables in separate lines' do
-      expect(rendered).to have_css('.js-build-variable', visible: false, text: 'TRIGGER_KEY_1')
-      expect(rendered).to have_css('.js-build-variable', visible: false, text: 'TRIGGER_KEY_2')
-      expect(rendered).to have_css('.js-build-value', visible: false, text: 'TRIGGER_VALUE_1')
-      expect(rendered).to have_css('.js-build-value', visible: false, text: 'TRIGGER_VALUE_2')
-    end
-  end
 end