diff --git a/app/controllers/repp/v1/invoices_controller.rb b/app/controllers/repp/v1/invoices_controller.rb
index 34c04ff72..5d37d6881 100644
--- a/app/controllers/repp/v1/invoices_controller.rb
+++ b/app/controllers/repp/v1/invoices_controller.rb
@@ -47,7 +47,7 @@ module Repp
                                                   .merge!(recipient: recipient) })
       end
 
-      api :post, '/repp/v1/invoices/:id/cancel'
+      api :put, '/repp/v1/invoices/:id/cancel'
       desc 'Cancel a specific invoice'
       def cancel
         action = Actions::InvoiceCancel.new(@invoice)
@@ -72,7 +72,7 @@ module Repp
           serializer = Serializers::Repp::Invoice.new(invoice, simplify: true)
           render_success(data: { invoice: serializer.to_json })
         else
-          handle_errors(deposit)
+          handle_non_epp_errors(deposit)
         end
       end
 
@@ -108,7 +108,7 @@ module Repp
       end
 
       def serialized_invoices(invoices)
-        return invoices.pluck(:number) unless index_params[:details] == 'true'
+        return invoices.map(&:number) unless index_params[:details] == 'true'
 
         simple = index_params[:simple] == 'true' || false
         invoices.map { |i| Serializers::Repp::Invoice.new(i, simplify: simple).to_json }
diff --git a/app/controllers/repp/v1/registrar/auth_controller.rb b/app/controllers/repp/v1/registrar/auth_controller.rb
index f91cc8637..ccc7d2e66 100644
--- a/app/controllers/repp/v1/registrar/auth_controller.rb
+++ b/app/controllers/repp/v1/registrar/auth_controller.rb
@@ -22,7 +22,7 @@ module Repp
           render_success(data: { token: token, username: user.username })
         end
 
-        api :put, '/repp/v1/registrar/auth/switch_user/:new_user_id'
+        api :put, '/repp/v1/registrar/auth/switch_user'
         desc 'Switch session to another api user'
         def switch_user
           new_user = ApiUser.find(auth_params[:new_user_id])
diff --git a/config/routes.rb b/config/routes.rb
index 6f336f4d4..2ea79e1c0 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -87,11 +87,11 @@ Rails.application.routes.draw do
       resources :invoices, only: %i[index show] do
         collection do
           get ':id/download', to: 'invoices#download'
-          get ':id/cancel', to: 'invoices#cancel'
           post 'add_credit'
         end
         member do
           post 'send_to_recipient', to: 'invoices#send_to_recipient'
+          put 'cancel', to: 'invoices#cancel'
         end
       end
       resources :auctions, only: %i[index]
diff --git a/test/integration/repp/v1/account/activities_list_test.rb b/test/integration/repp/v1/account/activities_list_test.rb
new file mode 100644
index 000000000..b492cc098
--- /dev/null
+++ b/test/integration/repp/v1/account/activities_list_test.rb
@@ -0,0 +1,70 @@
+require 'test_helper'
+
+class ReppV1AccountActivitiesListTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_returns_account_activities
+    get repp_v1_account_path, headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal @user.registrar.cash_account.activities.count, json[:data][:count]
+    assert_equal @user.registrar.cash_account.activities.count, json[:data][:activities].length
+
+    assert json[:data][:activities][0].is_a? Hash
+  end
+
+  def test_respects_limit
+    get repp_v1_account_path(limit: 1), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal 1, json[:data][:activities].length
+  end
+
+  def test_respects_offset
+    offset = 1
+    get repp_v1_account_path(offset: offset), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal (@user.registrar.cash_account.activities.count - offset), json[:data][:activities].length
+  end
+
+  def test_returns_account_activities_by_search_query
+    search_params = {
+      description_matches: '%renew%',
+    }
+    get repp_v1_account_path(q: search_params), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal json[:data][:activities].length, 1
+    assert json[:data][:activities][0].is_a? Hash
+  end
+
+  def test_returns_account_activities_by_sort_query
+    activity = account_activities(:renew_cash)
+    sort_params = {
+      s: 'activity_type asc',
+    }
+    get repp_v1_account_path(q: sort_params), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal @user.registrar.cash_account.activities.count, json[:data][:count]
+    assert_equal @user.registrar.cash_account.activities.count, json[:data][:activities].length
+    assert_equal json[:data][:activities][0][:description], activity.description
+  end
+end
diff --git a/test/integration/repp/v1/account/balance_test.rb b/test/integration/repp/v1/account/balance_test.rb
index a8416be0a..a4d41ed53 100644
--- a/test/integration/repp/v1/account/balance_test.rb
+++ b/test/integration/repp/v1/account/balance_test.rb
@@ -10,6 +10,8 @@ class ReppV1BalanceTest < ActionDispatch::IntegrationTest
     @auth_headers = { 'Authorization' => token }
   end
 
+  
+
   def test_can_query_balance
     get '/repp/v1/account/balance', headers: @auth_headers
     json = JSON.parse(response.body, symbolize_names: true)
diff --git a/test/integration/repp/v1/account/details_test.rb b/test/integration/repp/v1/account/details_test.rb
new file mode 100644
index 000000000..b0d359d74
--- /dev/null
+++ b/test/integration/repp/v1/account/details_test.rb
@@ -0,0 +1,22 @@
+require 'test_helper'
+
+class ReppV1AccountDetailsTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_returns_account_details
+    get '/repp/v1/account/details', headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    assert_equal @user.registrar.billing_email, json[:data][:account][:billing_email]
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/account/update_auto_reload_balance_test.rb b/test/integration/repp/v1/account/update_auto_reload_balance_test.rb
new file mode 100644
index 000000000..6201750c3
--- /dev/null
+++ b/test/integration/repp/v1/account/update_auto_reload_balance_test.rb
@@ -0,0 +1,69 @@
+require 'test_helper'
+
+class ReppV1AccountUpdateAutoReloadBalanceTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_updates_auto_reload_balance
+    amount = 100
+    threshold = 10
+    request_body = {
+      type: {
+        amount: amount,
+        threshold: threshold,
+      },
+    }
+
+    assert_nil @user.registrar.settings['balance_auto_reload']
+
+    post '/repp/v1/account/update_auto_reload_balance', headers: @auth_headers,
+                                                        params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Balance Auto-Reload setting has been updated', json[:message]
+
+    @user.registrar.reload
+
+    assert_equal amount, @user.registrar.settings['balance_auto_reload']['type']['amount']
+    assert_equal threshold, @user.registrar.settings['balance_auto_reload']['type']['threshold']
+  end
+
+  def test_returns_error_if_type_has_wrong_attributes
+    min_deposit = 10
+    request_body = {
+      type: {
+        amount: 5,
+        threshold: -1,
+      },
+    }
+    Setting.minimum_deposit = min_deposit
+
+    post '/repp/v1/account/update_auto_reload_balance', headers: @auth_headers,
+                                                        params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :bad_request
+    amount_error = "Amount must be greater than or equal to #{min_deposit.to_f}"
+    threshold = 'Threshold must be greater than or equal to 0'
+    assert_equal "#{amount_error}, #{threshold}", json[:message]
+  end
+
+  def test_disables_auto_reload_balance
+    get '/repp/v1/account/disable_auto_reload_balance', headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Balance Auto-Reload setting has been disabled', json[:message]
+
+    @user.registrar.reload
+
+    assert_nil @user.registrar.settings['balance_auto_reload']
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/account/update_details_test.rb b/test/integration/repp/v1/account/update_details_test.rb
new file mode 100644
index 000000000..3ab415cd8
--- /dev/null
+++ b/test/integration/repp/v1/account/update_details_test.rb
@@ -0,0 +1,30 @@
+require 'test_helper'
+
+class ReppV1AccountUpdateDetailsTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_updates_details
+    request_body =  {
+      account: {
+        billing_email: 'donaldtrump@yandex.ru',
+        iban: 'GB331111111111111111',
+      },
+    }
+
+    put '/repp/v1/account', headers: @auth_headers, params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Your account has been updated', json[:message]
+
+    assert_equal(request_body[:account][:billing_email], @user.registrar.billing_email)
+    assert_equal(request_body[:account][:iban], @user.registrar.iban)
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/contacts/list_test.rb b/test/integration/repp/v1/contacts/list_test.rb
index 6cc3e4669..979d3ea40 100644
--- a/test/integration/repp/v1/contacts/list_test.rb
+++ b/test/integration/repp/v1/contacts/list_test.rb
@@ -12,7 +12,7 @@ class ReppV1ContactsListTest < ActionDispatch::IntegrationTest
   def test_returns_registrar_contacts
     get repp_v1_contacts_path, headers: @auth_headers
     json = JSON.parse(response.body, symbolize_names: true)
- 
+
     assert_response :ok
 
     assert_equal @user.registrar.contacts.count, json[:data][:count]
@@ -21,7 +21,6 @@ class ReppV1ContactsListTest < ActionDispatch::IntegrationTest
     assert json[:data][:contacts][0].is_a? String
   end
 
-
   def test_returns_detailed_registrar_contacts
     get repp_v1_contacts_path(details: true), headers: @auth_headers
     json = JSON.parse(response.body, symbolize_names: true)
@@ -52,4 +51,32 @@ class ReppV1ContactsListTest < ActionDispatch::IntegrationTest
 
     assert_equal (@user.registrar.contacts.count - offset), json[:data][:contacts].length
   end
+
+  def test_returns_detailed_registrar_contacts_by_search_query
+    search_params = {
+      ident_type_eq: 'priv',
+    }
+    get repp_v1_contacts_path(details: true, q: search_params), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal json[:data][:contacts].length, 3
+    assert json[:data][:contacts][0].is_a? Hash
+  end
+
+  def test_returns_detailed_registrar_contacts_by_sort_query
+    contact = contacts(:william)
+    sort_params = {
+      s: 'name desc',
+    }
+    get repp_v1_contacts_path(details: true, q: sort_params), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal @user.registrar.contacts.count, json[:data][:count]
+    assert_equal @user.registrar.contacts.count, json[:data][:contacts].length
+    assert_equal json[:data][:contacts][0][:code], contact.code
+  end
 end
diff --git a/test/integration/repp/v1/contacts/search_test.rb b/test/integration/repp/v1/contacts/search_test.rb
new file mode 100644
index 000000000..ceeefc7be
--- /dev/null
+++ b/test/integration/repp/v1/contacts/search_test.rb
@@ -0,0 +1,43 @@
+require 'test_helper'
+
+class ReppV1ContactsSearchTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_searches_all_contacts_by_id
+    contact = contacts(:john)
+    get "/repp/v1/contacts/search/#{contact.code}", headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert json[:data].is_a? Array
+    assert_equal json[:data][0][:value], contact.code
+    assert_equal json[:data][0][:label], "#{contact.code} #{contact.name}"
+    assert_equal json[:data][0][:selected], true
+  end
+
+  def test_searches_all_contacts_by_query
+    get '/repp/v1/contacts/search', headers: @auth_headers, params: { query: 'j' }
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert json[:data].is_a? Array
+    assert_equal json[:data].length, 2
+    assert_equal json[:data][0][:selected], false
+    assert_equal json[:data][1][:selected], false
+  end
+
+  def test_searches_all_contacts_by_wrong_query
+    get '/repp/v1/contacts/search', headers: @auth_headers, params: { query: '000' }
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert json[:data].is_a? Array
+    assert_equal json[:data].length, 0
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/domains/list_test.rb b/test/integration/repp/v1/domains/list_test.rb
index 645947b57..205017a6c 100644
--- a/test/integration/repp/v1/domains/list_test.rb
+++ b/test/integration/repp/v1/domains/list_test.rb
@@ -64,4 +64,32 @@ class ReppV1DomainsListTest < ActionDispatch::IntegrationTest
     serialized_domain = Serializers::Repp::Domain.new(domain).to_json
     assert_equal serialized_domain.as_json, json[:data][:domain].as_json
   end
+
+  def test_returns_detailed_registrar_domains_by_search_query
+    search_params = {
+      name_matches: '%library%',
+    }
+    get repp_v1_domains_path(details: true, q: search_params), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal json[:data][:domains].length, 1
+    assert json[:data][:domains][0].is_a? Hash
+  end
+
+  def test_returns_detailed_registrar_domains_by_sort_query
+    domain = domains(:shop)
+    sort_params = {
+      s: 'name desc',
+    }
+    get repp_v1_domains_path(details: true, q: sort_params), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal @user.registrar.domains.count, json[:data][:count]
+    assert_equal @user.registrar.domains.count, json[:data][:domains].length
+    assert_equal json[:data][:domains][0][:name], domain.name
+  end
 end
diff --git a/test/integration/repp/v1/invoices/add_credit_test.rb b/test/integration/repp/v1/invoices/add_credit_test.rb
new file mode 100644
index 000000000..71f2c77d3
--- /dev/null
+++ b/test/integration/repp/v1/invoices/add_credit_test.rb
@@ -0,0 +1,94 @@
+require 'test_helper'
+
+class ReppV1InvoicesAddCreditTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+
+    @original_registry_vat_rate = Setting.registry_vat_prc
+    eis_response = OpenStruct.new(body: '{"everypay_link":"https://link.test"}')
+    Spy.on_instance_method(EisBilling::AddDeposits, :send_invoice).and_return(eis_response)
+    Spy.on_instance_method(EisBilling::BaseController, :authorized).and_return(true)
+  end
+
+  teardown do
+    Setting.registry_vat_prc = @original_registry_vat_rate
+  end
+
+  def test_generates_add_credit_invoice_with_billing_system
+    request_body = {
+      invoice: {
+        amount: 100,
+        description: 'Add credit',
+      },
+    }
+    Setting.registry_vat_prc = 0.1
+    ENV['billing_system_integrated'] = 'true'
+
+    if Feature.billing_system_integrated?
+      invoice_n = Invoice.order(number: :desc).last.number
+      stub_request(:post, 'https://eis_billing_system:3000/api/v1/invoice_generator/invoice_number_generator')
+        .to_return(status: 200, body: "{\"invoice_number\":\"#{invoice_n + 3}\"}", headers: {})
+      stub_request(:post, 'https://eis_billing_system:3000/api/v1/e_invoice/e_invoice')
+        .to_return(status: 200, body: '', headers: {})
+    end
+
+    post '/repp/v1/invoices/add_credit', headers: @auth_headers,
+                                         params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    assert_not json[:data][:invoice][:paid]
+    assert json[:data][:invoice][:payable]
+    assert json[:data][:invoice][:cancellable]
+    assert_equal json[:data][:invoice][:payment_link], 'https://link.test'
+    assert_equal json[:data][:invoice][:total], 110.to_f.to_s
+  end
+
+  def test_generates_add_credit_invoice_without_billing_system
+    request_body = {
+      invoice: {
+        amount: 100,
+        description: 'Add credit',
+      },
+    }
+    Setting.registry_vat_prc = 0.1
+    ENV['billing_system_integrated'] = 'false'
+
+    post '/repp/v1/invoices/add_credit', headers: @auth_headers,
+                                         params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    assert_not json[:data][:invoice][:paid]
+    assert json[:data][:invoice][:payable]
+    assert json[:data][:invoice][:cancellable]
+    assert_equal json[:data][:invoice][:total], 110.to_f.to_s
+  end
+
+  def test_generates_add_credit_invoice_with_invalid_amount
+    request_body = {
+      invoice: {
+        amount: 0.4,
+        description: 'Add credit',
+      },
+    }
+    Setting.minimum_deposit = 0.5
+
+    post '/repp/v1/invoices/add_credit', headers: @auth_headers,
+                                         params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :bad_request
+    assert_equal "Amount is too small. Minimum deposit is #{Setting.minimum_deposit} EUR", json[:message]
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/invoices/cancel_test.rb b/test/integration/repp/v1/invoices/cancel_test.rb
new file mode 100644
index 000000000..1041d1d1f
--- /dev/null
+++ b/test/integration/repp/v1/invoices/cancel_test.rb
@@ -0,0 +1,44 @@
+require 'test_helper'
+
+class ReppV1InvoicesCancelTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_cancels_invoice
+    invoice = invoices(:one)
+    invoice.account_activity = nil
+    assert invoice.cancellable?
+    stub_request(:post, 'https://eis_billing_system:3000/api/v1/invoice_generator/invoice_status')
+      .to_return(status: :ok, headers: {})
+
+    put "/repp/v1/invoices/#{invoice.id}/cancel", headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    invoice.reload
+    assert invoice.cancelled?
+    assert json[:data][:invoice].is_a? Hash
+  end
+
+  def test_cancels_uncancellable_invoice
+    invoice = invoices(:one)
+    assert_not invoice.cancellable?
+
+    put "/repp/v1/invoices/#{invoice.id}/cancel", headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :bad_request
+    assert_equal 'Invoice status prohibits operation', json[:message]
+
+    invoice.reload
+    assert_not invoice.cancelled?
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/invoices/download_test.rb b/test/integration/repp/v1/invoices/download_test.rb
new file mode 100644
index 000000000..cbb9de585
--- /dev/null
+++ b/test/integration/repp/v1/invoices/download_test.rb
@@ -0,0 +1,22 @@
+require 'test_helper'
+
+class ReppV1InvoicesDownloadTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_returns_invoice_as_pdf
+    invoice = @user.registrar.invoices.first
+
+    get "/repp/v1/invoices/#{invoice.id}/download", headers: @auth_headers
+
+    assert_response :ok
+    assert_equal 'application/pdf', response.headers['Content-Type']
+    assert_equal "attachment; filename=\"Invoice-2.pdf\"; filename*=UTF-8''Invoice-2.pdf", response.headers['Content-Disposition']
+    assert_not_empty response.body
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/invoices/list_test.rb b/test/integration/repp/v1/invoices/list_test.rb
new file mode 100644
index 000000000..5dfe2d53f
--- /dev/null
+++ b/test/integration/repp/v1/invoices/list_test.rb
@@ -0,0 +1,85 @@
+require 'test_helper'
+
+class ReppV1InvoicesListTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_returns_registrar_invoices
+    get repp_v1_invoices_path, headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal @user.registrar.invoices.count, json[:data][:count]
+    assert_equal @user.registrar.invoices.count, json[:data][:invoices].length
+
+    assert json[:data][:invoices][0].is_a? Integer
+  end
+
+  def test_returns_detailed_registrar_invoices
+    get repp_v1_invoices_path(details: true), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal @user.registrar.invoices.count, json[:data][:count]
+    assert_equal @user.registrar.invoices.count, json[:data][:invoices].length
+
+    assert json[:data][:invoices][0].is_a? Hash
+  end
+
+  def test_returns_detailed_registrar_invoices_by_search_query
+    invoice = @user.registrar.invoices.last
+    invoice.update(number: 15_008)
+    search_params = {
+      number_gteq: 15_000,
+    }
+    get repp_v1_invoices_path(details: true, q: search_params), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal json[:data][:invoices].length, 1
+    assert json[:data][:invoices][0].is_a? Hash
+    assert_equal json[:data][:invoices][0][:id], invoice.id
+  end
+
+  def test_returns_detailed_registrar_invoices_by_sort_query
+    invoice = invoices(:unpaid)
+    sort_params = {
+      s: 'number desc',
+    }
+    get repp_v1_invoices_path(details: true, q: sort_params), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal @user.registrar.invoices.count, json[:data][:count]
+    assert_equal @user.registrar.invoices.count, json[:data][:invoices].length
+    assert_equal json[:data][:invoices][0][:id], invoice.id
+  end
+
+  def test_respects_limit
+    get repp_v1_invoices_path(details: true, limit: 1), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal 1, json[:data][:invoices].length
+  end
+
+  def test_respects_offset
+    offset = 1
+    get repp_v1_invoices_path(details: true, offset: offset), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+
+    assert_equal (@user.registrar.invoices.count - offset), json[:data][:invoices].length
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/invoices/send_test.rb b/test/integration/repp/v1/invoices/send_test.rb
new file mode 100644
index 000000000..77fe9997f
--- /dev/null
+++ b/test/integration/repp/v1/invoices/send_test.rb
@@ -0,0 +1,39 @@
+require 'test_helper'
+
+class ReppV1InvoicesSendTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_sends_invoice_to_recipient
+    invoice = invoices(:one)
+    recipient = 'donaldtrump@yandex.ru'
+    request_body = {
+      invoice: {
+        id: invoice.id,
+        recipient: recipient,
+      },
+    }
+    post "/repp/v1/invoices/#{invoice.id}/send_to_recipient", headers: @auth_headers,
+                                                              params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_equal 1, invoice.number
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    assert_equal json[:data][:invoice][:id], invoice.id
+    assert_equal json[:data][:invoice][:recipient], recipient
+    email = ActionMailer::Base.deliveries.last
+    assert_emails 1
+    assert_equal [recipient], email.to
+    assert_equal 'Invoice no. 1', email.subject
+    assert email.attachments['invoice-1.pdf']
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/invoices/show_test.rb b/test/integration/repp/v1/invoices/show_test.rb
new file mode 100644
index 000000000..74feb42ac
--- /dev/null
+++ b/test/integration/repp/v1/invoices/show_test.rb
@@ -0,0 +1,33 @@
+require 'test_helper'
+
+class ReppV1InvoicesShowTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_returns_error_when_not_found
+    get repp_v1_invoice_path(id: 'definitelynotexistant'), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :not_found
+    assert_equal 2303, json[:code]
+    assert_equal 'Object does not exist', json[:message]
+  end
+
+  def test_shows_existing_invoice
+    invoice = @user.registrar.invoices.first
+
+    get repp_v1_invoice_path(id: invoice.id), headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    assert_equal invoice.id, json[:data][:invoice][:id]
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/registrar/auth/check_info_test.rb b/test/integration/repp/v1/registrar/auth/check_info_test.rb
new file mode 100644
index 000000000..65b2cf5f4
--- /dev/null
+++ b/test/integration/repp/v1/registrar/auth/check_info_test.rb
@@ -0,0 +1,39 @@
+require 'test_helper'
+
+class ReppV1RegistrarAuthCheckInfoTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_returns_valid_user_auth_values
+    get '/repp/v1/registrar/auth', headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    assert_equal json[:data][:username], @user.username
+    assert json[:data][:roles].include? 'super'
+    assert_equal json[:data][:registrar_name], 'Best Names'
+    assert_equal json[:data][:balance][:amount].to_f, @user.registrar.cash_account.balance
+    assert json[:data][:abilities].is_a? Hash
+  end
+
+  def test_invalid_user_login
+    token = Base64.encode64("#{@user.username}:0066600")
+    token = "Basic #{token}"
+
+    auth_headers = { 'Authorization' => token }
+
+    get '/repp/v1/registrar/auth', headers: auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :unauthorized
+    assert_equal json[:message], 'Invalid authorization information'
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/registrar/auth/switch_user_test.rb b/test/integration/repp/v1/registrar/auth/switch_user_test.rb
new file mode 100644
index 000000000..beb5c0727
--- /dev/null
+++ b/test/integration/repp/v1/registrar/auth/switch_user_test.rb
@@ -0,0 +1,52 @@
+require 'test_helper'
+
+class ReppV1RegistrarSwitchUserTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_switches_to_linked_api_user
+    new_user = users(:api_goodnames)
+    new_user.update(identity_code: '1234')
+    request_body = {
+      auth: {
+        new_user_id: new_user.id,
+      },
+    }
+
+    put '/repp/v1/registrar/auth/switch_user', headers: @auth_headers, params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal "You are now signed in as a user \"#{new_user.username}\"", json[:message]
+
+    user_token = Base64.urlsafe_encode64("#{new_user.username}:#{new_user.plain_text_password}")
+    assert_equal json[:data][:token], user_token
+    assert_equal json[:data][:registrar][:username], new_user.username
+    assert json[:data][:registrar][:roles].include? 'super'
+    assert_equal json[:data][:registrar][:registrar_name], 'Good Names'
+    assert_equal json[:data][:registrar][:balance][:amount].to_f, new_user.registrar.cash_account.balance
+    assert json[:data][:registrar][:abilities].is_a? Hash
+  end
+
+  def test_switches_to_unlinked_api_user
+    new_user = users(:api_goodnames)
+    new_user.update(identity_code: '4444')
+    request_body = {
+      auth: {
+        new_user_id: new_user.id,
+      },
+    }
+
+    put '/repp/v1/registrar/auth/switch_user', headers: @auth_headers, params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :bad_request
+    assert_equal 'Cannot switch to unlinked user', json[:message]
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/registrar/auth/tara_callback_test.rb b/test/integration/repp/v1/registrar/auth/tara_callback_test.rb
new file mode 100644
index 000000000..56d881c87
--- /dev/null
+++ b/test/integration/repp/v1/registrar/auth/tara_callback_test.rb
@@ -0,0 +1,46 @@
+require 'test_helper'
+
+class ReppV1RegistrarAuthTaraCallbackTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    username = nil
+    password = nil
+    token = Base64.encode64("#{username}:#{password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_validates_user_from_omniauth_params
+    request_body = {
+      auth: {
+        uid: 'EE1234',
+      },
+    }
+
+    post '/repp/v1/registrar/auth/tara_callback', headers: @auth_headers, params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    user_token = Base64.urlsafe_encode64("#{@user.username}:#{@user.plain_text_password}")
+    assert_equal json[:data][:username], @user.username
+    assert_equal json[:data][:token], user_token
+  end
+
+  def test_invalidates_user_with_wrong_omniauth_params
+    request_body = {
+      auth: {
+        uid: '33333',
+      },
+    }
+
+    post '/repp/v1/registrar/auth/tara_callback', headers: @auth_headers, params: request_body
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :bad_request
+    assert_equal 'No such user', json[:message]
+  end
+end
\ No newline at end of file
diff --git a/test/integration/repp/v1/registrar/summary_test.rb b/test/integration/repp/v1/registrar/summary_test.rb
new file mode 100644
index 000000000..257eb067f
--- /dev/null
+++ b/test/integration/repp/v1/registrar/summary_test.rb
@@ -0,0 +1,44 @@
+require 'test_helper'
+
+class ReppV1RegistrarSummaryTest < ActionDispatch::IntegrationTest
+  def setup
+    @user = users(:api_bestnames)
+    token = Base64.encode64("#{@user.username}:#{@user.plain_text_password}")
+    token = "Basic #{token}"
+
+    @auth_headers = { 'Authorization' => token }
+  end
+
+  def test_checks_user_summary_info
+    get '/repp/v1/registrar/summary', headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    assert_equal json[:data][:username], @user.username
+    assert_equal json[:data][:registrar_name], 'Best Names'
+    assert_equal json[:data][:domains], @user.registrar.domains.count
+    assert_equal json[:data][:contacts], @user.registrar.contacts.count
+    assert json[:data][:notification].is_a? Hash
+    assert_equal json[:data][:notifications_count], @user.unread_notifications.count
+  end
+
+  def test_checks_limited_user_summary_info
+    @user.update(roles: ['billing'])
+    get '/repp/v1/registrar/summary', headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal 1000, json[:code]
+    assert_equal 'Command completed successfully', json[:message]
+
+    assert_equal json[:data][:username], @user.username
+    assert_equal json[:data][:registrar_name], 'Best Names'
+    assert_nil json[:data][:domains]
+    assert_nil json[:data][:contacts]
+    assert_nil json[:data][:notification]
+    assert_nil json[:data][:notifications_count]
+  end
+end
\ No newline at end of file