diff --git a/app/concepts/project/operation/create_remix.rb b/app/concepts/project/operation/create_remix.rb
index 22a7c3818..ac4cfdeb5 100644
--- a/app/concepts/project/operation/create_remix.rb
+++ b/app/concepts/project/operation/create_remix.rb
@@ -5,39 +5,41 @@ module Operation
     class CreateRemix
       require 'operation_response'
 
-      def self.call(params, user_id)
-        response = OperationResponse.new
-
-        validate_params(response, params, user_id)
-        return response if response.failure?
+      class << self
+        def call(params:, user_id:, original_project:)
+          response = OperationResponse.new
 
-        remix_project(response, params, user_id)
-        response
-      end
+          validate_params(response, params, user_id, original_project)
+          remix_project(response, params, user_id, original_project)
+          response
+        end
 
-      class << self
         private
 
-        def validate_params(response, params, user_id)
-          valid = params[:project_id].present? && user_id.present?
-          response[:error] = 'Invalid parameters' unless valid
+        def validate_params(response, params, user_id, original_project)
+          valid = params[:identifier].present? && user_id.present? && original_project.present?
+          response[:error] = I18n.t('errors.project.remixing.invalid_params') unless valid
         end
 
-        def remix_project(response, params, user_id)
-          original_project = Project.find_by!(identifier: params[:project_id])
+        def remix_project(response, params, user_id, original_project)
+          return if response[:error]
 
-          response[:project] = create_remix(original_project, user_id)
+          response[:project] = create_remix(original_project, params, user_id)
 
-          response[:error] = 'Unable to create project' unless response[:project].save
+          response[:error] = I18n.t('errors.project.remixing.cannot_save') unless response[:project].save
           response
         end
 
-        def create_remix(original_project, user_id)
-          original_project.dup.tap do |proj|
+        def create_remix(original_project, params, user_id)
+          remix = original_project.dup.tap do |proj|
             proj.user_id = user_id
-            proj.components = original_project.components.map(&:dup)
             proj.remixed_from_id = original_project.id
           end
+
+          params[:components].each do |x|
+            remix.components.build(x.slice(:name, :extension, :content, :index))
+          end
+          remix
         end
       end
     end
diff --git a/app/concepts/project/operation/update.rb b/app/concepts/project/operation/update.rb
index d210d321f..cfde67f70 100644
--- a/app/concepts/project/operation/update.rb
+++ b/app/concepts/project/operation/update.rb
@@ -5,7 +5,7 @@ module Operation
     class Update
       require 'operation_response'
 
-      def self.call(params, project)
+      def self.call(params:, project:)
         response = setup_response(project)
 
         setup_deletions(response, params)
diff --git a/app/controllers/api/projects/remixes_controller.rb b/app/controllers/api/projects/remixes_controller.rb
index f24a87963..cc57d69cf 100644
--- a/app/controllers/api/projects/remixes_controller.rb
+++ b/app/controllers/api/projects/remixes_controller.rb
@@ -6,7 +6,9 @@ class RemixesController < ApiController
       before_action :require_oauth_user
 
       def create
-        result = Project::Operation::CreateRemix.call(remix_params, oauth_user_id)
+        result = Project::Operation::CreateRemix.call(params: remix_params,
+                                                      user_id: oauth_user_id,
+                                                      original_project: project)
 
         if result.success?
           @project = result[:project]
@@ -18,8 +20,15 @@ def create
 
       private
 
+      def project
+        @project ||= Project.find_by!(identifier: params[:project_id])
+      end
+
       def remix_params
-        params.permit(:project_id)
+        params.require(:project)
+              .permit(:name,
+                      :identifier,
+                      components: %i[id name extension content index])
       end
     end
   end
diff --git a/app/controllers/api/projects_controller.rb b/app/controllers/api/projects_controller.rb
index 0de3c02c5..e3f15ee1f 100644
--- a/app/controllers/api/projects_controller.rb
+++ b/app/controllers/api/projects_controller.rb
@@ -12,7 +12,7 @@ def show
     end
 
     def update
-      result = Project::Operation::Update.call(project_params, @project)
+      result = Project::Operation::Update.call(params: project_params, project: @project)
 
       if result.success?
         render :show, formats: [:json]
diff --git a/config/locales/en.yml b/config/locales/en.yml
index d5379a51c..70e5074e6 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -5,3 +5,6 @@ en:
         delete_default_component: 'Cannot delete default file'
         change_default_name: 'Cannot amend default file name'
         change_default_extension: 'Cannot amend default file extension'
+      remixing:
+        invalid_params: 'Invalid parameters'
+        cannot_save: 'Cannot create project remix'
diff --git a/spec/concepts/project/operation/create_remix_spec.rb b/spec/concepts/project/operation/create_remix_spec.rb
index c2c58e221..4bc05f711 100644
--- a/spec/concepts/project/operation/create_remix_spec.rb
+++ b/spec/concepts/project/operation/create_remix_spec.rb
@@ -3,78 +3,148 @@
 require 'rails_helper'
 
 RSpec.describe Project::Operation::CreateRemix, type: :unit do
-  subject(:create_remix) { described_class.call(params, user_id) }
+  subject(:create_remix) { described_class.call(params: remix_params, user_id: user_id, original_project: original_project) }
 
   let(:user_id) { 'e0675b6c-dc48-4cd6-8c04-0f7ac05af51a' }
   let!(:original_project) { create(:project, :with_components) }
+  let(:remix_params) do
+    component = original_project.components.first
+    {
+      name: original_project.name,
+      identifier: original_project.identifier,
+      components: [
+        {
+          id: component.id,
+          name: component.name,
+          extension: component.extension,
+          content: 'some updated component content',
+          index: component.index
+        }
+      ]
+    }
+  end
 
   before do
     mock_phrase_generation
   end
 
   describe '.call' do
-    context 'when all params valid' do
-      let(:params) { { project_id: original_project.identifier } }
+    let(:params) { { project_id: original_project.identifier } }
 
-      it 'returns success' do
-        result = create_remix
-        expect(result.success?).to eq(true)
-      end
+    it 'returns success' do
+      result = create_remix
+      expect(result.success?).to eq(true)
+    end
+
+    it 'creates new project' do
+      expect { create_remix }.to change(Project, :count).by(1)
+    end
+
+    it 'assigns a new identifer to new project' do
+      result = create_remix
+      remixed_project = result[:project]
+      expect(remixed_project.identifier).not_to eq(original_project.identifier)
+    end
+
+    it 'assigns user_id to new project' do
+      remixed_project = create_remix[:project]
+      expect(remixed_project.user_id).to eq(user_id)
+    end
+
+    it 'duplicates properties on new project' do
+      remixed_project = create_remix[:project]
 
-      it 'creates new project' do
-        expect { create_remix }.to change(Project, :count).by(1)
+      remixed_attrs = remixed_project.attributes.symbolize_keys.slice(:name, :project_type)
+      original_attrs = original_project.attributes.symbolize_keys.slice(:name, :project_type)
+      expect(remixed_attrs).to eq(original_attrs)
+    end
+
+    it 'creates new components' do
+      expect { create_remix }.to change(Component, :count).by(1)
+    end
+
+    it 'persists changes made to submitted components' do
+      remixed_project = create_remix[:project]
+      expect(remixed_project.components.first.content).to eq('some updated component content')
+    end
+
+    context 'when a new component has been added before remixing' do
+      let(:new_component_params) { { name: 'added_component', extension: 'py', content: 'some added component content', index: 9999 } }
+
+      before do
+        remix_params[:components] << new_component_params
       end
 
-      it 'assigns a new identifer to new project' do
-        result = create_remix
-        remixed_project = result[:project]
-        expect(remixed_project.identifier).not_to eq(original_project.identifier)
+      it 'creates all components' do
+        expect { create_remix }.to change(Component, :count).by(2)
       end
 
-      it 'assigns user_id to new project' do
+      it 'persists the new component' do
         remixed_project = create_remix[:project]
-        expect(remixed_project.user_id).to eq(user_id)
+        expect(remixed_project.components.last.attributes.symbolize_keys).to include(new_component_params)
       end
+    end
 
-      it 'duplicates properties on new project' do
-        remixed_project = create_remix[:project]
+    context 'when user_id is not present' do
+      let(:user_id) { nil }
+      let(:params) { { project_id: original_project.identifier } }
 
-        remixed_attrs = remixed_project.attributes.symbolize_keys.slice(:name, :project_type)
-        original_attrs = original_project.attributes.symbolize_keys.slice(:name, :project_type)
-        expect(remixed_attrs).to eq(original_attrs)
+      it 'returns failure' do
+        result = create_remix
+        expect(result.failure?).to eq(true)
       end
 
-      it 'duplicates project components' do
-        remixed_props_array = component_array_props(create_remix[:project].components)
-        original_props_array = component_array_props(original_project.components)
+      it 'returns error message' do
+        result = create_remix
+        expect(result[:error]).to eq(I18n.t('errors.project.remixing.invalid_params'))
+      end
 
-        expect(remixed_props_array).to match_array(original_props_array)
+      it 'does not create new project' do
+        expect { create_remix }.not_to change(Project, :count)
       end
     end
 
-    context 'when user_id is not present' do
-      let(:user_id) { nil }
-      let(:params) { { project_id: original_project.identifier } }
+    context 'when original project is not present' do
+      subject(:create_remix) { described_class.call(params: remix_params, user_id: user_id, original_project: nil) }
 
       it 'returns failure' do
         result = create_remix
         expect(result.failure?).to eq(true)
       end
 
+      it 'returns error message' do
+        result = create_remix
+        expect(result[:error]).to eq(I18n.t('errors.project.remixing.invalid_params'))
+      end
+
       it 'does not create new project' do
         expect { create_remix }.not_to change(Project, :count)
       end
     end
-  end
 
-  def component_array_props(components)
-    components.map do |x|
-      {
-        name: x.name,
-        content: x.content,
-        extension: x.extension,
-        index: x.index
-      }
+    context 'when project components are invalid' do
+      let(:invalid_component_params) { { name: 'added_component', extension: 'py', content: '' } }
+
+      before do
+        remix_params[:components] << invalid_component_params
+      end
+
+      it 'returns failure' do
+        expect(create_remix.failure?).to eq(true)
+      end
+
+      it 'sets error message' do
+        expect(create_remix[:error]).to eq(I18n.t('errors.project.remixing.cannot_save'))
+      end
     end
   end
+
+  def component_props(component)
+    {
+      name: component.name,
+      content: component.content,
+      extension: component.extension,
+      index: component.index
+    }
+  end
 end
diff --git a/spec/concepts/project/operation/update_default_component_spec.rb b/spec/concepts/project/operation/update_default_component_spec.rb
index 7d888c323..4c55207bc 100644
--- a/spec/concepts/project/operation/update_default_component_spec.rb
+++ b/spec/concepts/project/operation/update_default_component_spec.rb
@@ -3,7 +3,7 @@
 require 'rails_helper'
 
 RSpec.describe Project::Operation::Update, type: :unit do
-  subject(:update) { described_class.call(project_params, project) }
+  subject(:update) { described_class.call(params: project_params, project: project) }
 
   let!(:project) { create(:project, :with_default_component) }
   let(:default_component) { project.components.first }
diff --git a/spec/concepts/project/operation/update_delete_components_spec.rb b/spec/concepts/project/operation/update_delete_components_spec.rb
index b33ec43d7..ad08160f3 100644
--- a/spec/concepts/project/operation/update_delete_components_spec.rb
+++ b/spec/concepts/project/operation/update_delete_components_spec.rb
@@ -3,7 +3,7 @@
 require 'rails_helper'
 
 RSpec.describe Project::Operation::Update, type: :unit do
-  subject(:update) { described_class.call(project_params, project) }
+  subject(:update) { described_class.call(params: project_params, project: project) }
 
   let!(:project) { create(:project, :with_default_component, :with_components) }
   let(:component_to_delete) { project.components.last }
diff --git a/spec/concepts/project/operation/update_invalid_spec.rb b/spec/concepts/project/operation/update_invalid_spec.rb
index 2725c1fac..449faa2fd 100644
--- a/spec/concepts/project/operation/update_invalid_spec.rb
+++ b/spec/concepts/project/operation/update_invalid_spec.rb
@@ -8,7 +8,7 @@
       name: 'updated project name',
       components: [default_component_params, edited_component_params, new_component_params]
     }
-    described_class.call(params, project)
+    described_class.call(params: params, project: project)
   end
 
   let!(:project) { create(:project, :with_default_component, :with_components, component_count: 2) }
diff --git a/spec/concepts/project/operation/update_spec.rb b/spec/concepts/project/operation/update_spec.rb
index e815ccdd2..a0ea8a655 100644
--- a/spec/concepts/project/operation/update_spec.rb
+++ b/spec/concepts/project/operation/update_spec.rb
@@ -8,7 +8,7 @@
       name: 'updated project name',
       components: component_params
     }
-    described_class.call(params, project)
+    described_class.call(params: params, project: project)
   end
 
   let!(:project) { create(:project, :with_default_component, :with_components) }
diff --git a/spec/factories/component.rb b/spec/factories/component.rb
index 20b3b7841..debe18f42 100644
--- a/spec/factories/component.rb
+++ b/spec/factories/component.rb
@@ -6,6 +6,7 @@
     extension { 'py' }
     sequence(:index) { |n| n }
     default { false }
+    content { Faker::Lorem.paragraph }
     project
 
     factory :default_python_component do
diff --git a/spec/request/projects/remix_spec.rb b/spec/request/projects/remix_spec.rb
index bb8a28fc7..430d43e93 100644
--- a/spec/request/projects/remix_spec.rb
+++ b/spec/request/projects/remix_spec.rb
@@ -1,10 +1,18 @@
 # frozen_string_literal: true
 
 require 'rails_helper'
+require_relative '../../../lib/operation_response'
 
 RSpec.describe 'Remix requests', type: :request do
   let!(:original_project) { create(:project) }
   let(:user_id) { 'e0675b6c-dc48-4cd6-8c04-0f7ac05af51a' }
+  let(:project_params) do
+    {
+      name: original_project.name,
+      identifier: original_project.identifier,
+      components: []
+    }
+  end
 
   describe 'create' do
     before do
@@ -13,22 +21,44 @@
 
     context 'when auth is correct' do
       before do
-        mock_oauth_user
+        mock_oauth_user(user_id)
       end
 
       it 'returns success response' do
-        post "/api/projects/#{original_project.identifier}/remix"
+        post "/api/projects/#{original_project.identifier}/remix", params: { project: project_params }
 
         expect(response.status).to eq(200)
       end
 
       it 'returns 404 response if invalid project' do
-        post '/api/projects/no-such-project/remix'
+        project_params[:identifier] = 'no-such-project'
+        post '/api/projects/no-such-project/remix', params: { project: project_params }
 
         expect(response.status).to eq(404)
       end
     end
 
+    context 'when project can not be saved' do
+      before do
+        mock_oauth_user(user_id)
+        error_response = OperationResponse.new
+        error_response[:error] = 'Something went wrong'
+        allow(Project::Operation::CreateRemix).to receive(:call).and_return(error_response)
+      end
+
+      it 'returns 400' do
+        post "/api/projects/#{original_project.identifier}/remix", params: { project: project_params }
+
+        expect(response.status).to eq(400)
+      end
+
+      it 'returns error message' do
+        post "/api/projects/#{original_project.identifier}/remix", params: { project: project_params }
+
+        expect(response.body).to eq({ error: 'Something went wrong' }.to_json)
+      end
+    end
+
     context 'when auth is invalid' do
       it 'returns unauthorized' do
         post "/api/projects/#{original_project.identifier}/remix"
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 5d227ba75..7db67711e 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -86,7 +86,7 @@
   #   # order dependency and want to debug it, you can fix the order by providing
   #   # the seed, which is printed after each run.
   #   #     --seed 1234
-  #   config.order = :random
+  config.order = :random
   #
   #   # Seed global randomization in this process using the `--seed` CLI option.
   #   # Setting this allows you to use `--seed` to deterministically reproduce