diff --git a/.gitignore b/.gitignore
index a3cfb8d..084eed2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -42,7 +42,9 @@ EESTIINTERNETISA.p12
 
 docker-compose.yml
 
-vendor/gems
+Dockerfile.dev
+
+# vendor/gems
 /public/assets
 /public/packs
 /public/packs-test
diff --git a/Gemfile b/Gemfile
index 417f3f7..242964f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,7 @@ git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 ruby '3.2.0'
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails', branch: 'main'
-gem 'rails', '~> 7.1.3'
+gem 'rails', '~> 7.1.3.4'
 gem 'pg', '~> 1.1'
 gem 'puma', '~> 6.4.0'
 gem 'redis', '~> 5.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index 37044a2..79b7681 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -37,35 +37,35 @@ GIT
 GEM
   remote: https://rubygems.org/
   specs:
-    actioncable (7.1.3.2)
-      actionpack (= 7.1.3.2)
-      activesupport (= 7.1.3.2)
+    actioncable (7.1.3.4)
+      actionpack (= 7.1.3.4)
+      activesupport (= 7.1.3.4)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
       zeitwerk (~> 2.6)
-    actionmailbox (7.1.3.2)
-      actionpack (= 7.1.3.2)
-      activejob (= 7.1.3.2)
-      activerecord (= 7.1.3.2)
-      activestorage (= 7.1.3.2)
-      activesupport (= 7.1.3.2)
+    actionmailbox (7.1.3.4)
+      actionpack (= 7.1.3.4)
+      activejob (= 7.1.3.4)
+      activerecord (= 7.1.3.4)
+      activestorage (= 7.1.3.4)
+      activesupport (= 7.1.3.4)
       mail (>= 2.7.1)
       net-imap
       net-pop
       net-smtp
-    actionmailer (7.1.3.2)
-      actionpack (= 7.1.3.2)
-      actionview (= 7.1.3.2)
-      activejob (= 7.1.3.2)
-      activesupport (= 7.1.3.2)
+    actionmailer (7.1.3.4)
+      actionpack (= 7.1.3.4)
+      actionview (= 7.1.3.4)
+      activejob (= 7.1.3.4)
+      activesupport (= 7.1.3.4)
       mail (~> 2.5, >= 2.5.4)
       net-imap
       net-pop
       net-smtp
       rails-dom-testing (~> 2.2)
-    actionpack (7.1.3.2)
-      actionview (= 7.1.3.2)
-      activesupport (= 7.1.3.2)
+    actionpack (7.1.3.4)
+      actionview (= 7.1.3.4)
+      activesupport (= 7.1.3.4)
       nokogiri (>= 1.8.5)
       racc
       rack (>= 2.2.4)
@@ -73,35 +73,35 @@ GEM
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.2)
       rails-html-sanitizer (~> 1.6)
-    actiontext (7.1.3.2)
-      actionpack (= 7.1.3.2)
-      activerecord (= 7.1.3.2)
-      activestorage (= 7.1.3.2)
-      activesupport (= 7.1.3.2)
+    actiontext (7.1.3.4)
+      actionpack (= 7.1.3.4)
+      activerecord (= 7.1.3.4)
+      activestorage (= 7.1.3.4)
+      activesupport (= 7.1.3.4)
       globalid (>= 0.6.0)
       nokogiri (>= 1.8.5)
-    actionview (7.1.3.2)
-      activesupport (= 7.1.3.2)
+    actionview (7.1.3.4)
+      activesupport (= 7.1.3.4)
       builder (~> 3.1)
       erubi (~> 1.11)
       rails-dom-testing (~> 2.2)
       rails-html-sanitizer (~> 1.6)
-    activejob (7.1.3.2)
-      activesupport (= 7.1.3.2)
+    activejob (7.1.3.4)
+      activesupport (= 7.1.3.4)
       globalid (>= 0.3.6)
-    activemodel (7.1.3.2)
-      activesupport (= 7.1.3.2)
-    activerecord (7.1.3.2)
-      activemodel (= 7.1.3.2)
-      activesupport (= 7.1.3.2)
+    activemodel (7.1.3.4)
+      activesupport (= 7.1.3.4)
+    activerecord (7.1.3.4)
+      activemodel (= 7.1.3.4)
+      activesupport (= 7.1.3.4)
       timeout (>= 0.4.0)
-    activestorage (7.1.3.2)
-      actionpack (= 7.1.3.2)
-      activejob (= 7.1.3.2)
-      activerecord (= 7.1.3.2)
-      activesupport (= 7.1.3.2)
+    activestorage (7.1.3.4)
+      actionpack (= 7.1.3.4)
+      activejob (= 7.1.3.4)
+      activerecord (= 7.1.3.4)
+      activesupport (= 7.1.3.4)
       marcel (~> 1.0)
-    activesupport (7.1.3.2)
+    activesupport (7.1.3.4)
       base64
       bigdecimal
       concurrent-ruby (~> 1.0, >= 1.0.2)
@@ -360,20 +360,20 @@ GEM
     rackup (1.0.0)
       rack (< 3)
       webrick
-    rails (7.1.3.2)
-      actioncable (= 7.1.3.2)
-      actionmailbox (= 7.1.3.2)
-      actionmailer (= 7.1.3.2)
-      actionpack (= 7.1.3.2)
-      actiontext (= 7.1.3.2)
-      actionview (= 7.1.3.2)
-      activejob (= 7.1.3.2)
-      activemodel (= 7.1.3.2)
-      activerecord (= 7.1.3.2)
-      activestorage (= 7.1.3.2)
-      activesupport (= 7.1.3.2)
+    rails (7.1.3.4)
+      actioncable (= 7.1.3.4)
+      actionmailbox (= 7.1.3.4)
+      actionmailer (= 7.1.3.4)
+      actionpack (= 7.1.3.4)
+      actiontext (= 7.1.3.4)
+      actionview (= 7.1.3.4)
+      activejob (= 7.1.3.4)
+      activemodel (= 7.1.3.4)
+      activerecord (= 7.1.3.4)
+      activestorage (= 7.1.3.4)
+      activesupport (= 7.1.3.4)
       bundler (>= 1.15.0)
-      railties (= 7.1.3.2)
+      railties (= 7.1.3.4)
     rails-dom-testing (2.2.0)
       activesupport (>= 5.0.0)
       minitest
@@ -384,9 +384,9 @@ GEM
     rails-i18n (7.0.8)
       i18n (>= 0.7, < 2)
       railties (>= 6.0.0, < 8)
-    railties (7.1.3.2)
-      actionpack (= 7.1.3.2)
-      activesupport (= 7.1.3.2)
+    railties (7.1.3.4)
+      actionpack (= 7.1.3.4)
+      activesupport (= 7.1.3.4)
       irb
       rackup (>= 1.0.0)
       rake (>= 12.2)
@@ -571,7 +571,7 @@ DEPENDENCIES
   pg (~> 1.1)
   pg_search
   puma (~> 6.4.0)
-  rails (~> 7.1.3)
+  rails (~> 7.1.3.4)
   redis (~> 5.0)
   rexml
   rspec-rails
diff --git a/app/controllers/api/v1/invoice_generator/oneoff_controller.rb b/app/controllers/api/v1/invoice_generator/oneoff_controller.rb
index abbca5e..f86df67 100644
--- a/app/controllers/api/v1/invoice_generator/oneoff_controller.rb
+++ b/app/controllers/api/v1/invoice_generator/oneoff_controller.rb
@@ -9,11 +9,13 @@ class OneoffController < Api::V1::InvoiceGenerator::BaseController
           The link where the user must be redirected after payment. Along with the transition also on this link comes the data about the payment. This is a kind of redirect_url and callback_url
         HERE
         param :reference_number, String, required: false
+        param :amount, String, required: false
 
         def create
           response = Oneoff.call(invoice_number: params[:invoice_number],
                                  customer_url: params[:customer_url],
-                                 reference_number: params[:reference_number])
+                                 reference_number: params[:reference_number],
+                                 amount: params[:amount])
           if response.result?
             render json: { 'message' => 'Link created',
                            'oneoff_redirect_link' => response.instance['payment_link'] },
diff --git a/app/models/invoice.rb b/app/models/invoice.rb
index efea4f5..34d6217 100644
--- a/app/models/invoice.rb
+++ b/app/models/invoice.rb
@@ -15,7 +15,7 @@ class Invoice < ApplicationRecord
                                      }
 
   enum affiliation: { regular: 0, auction_deposit: 1, linkpay: 2 }
-  enum status: { unpaid: 0, paid: 1, cancelled: 2, failed: 3, refunded: 4, overdue: 5 }
+  enum status: { unpaid: 0, paid: 1, cancelled: 2, failed: 3, refunded: 4, overdue: 5, partially_paid: 6 }
 
   scope :with_status, lambda { |status|
     where(status:) if status.present?
@@ -29,6 +29,10 @@ class Invoice < ApplicationRecord
     where(transaction_amount: low.to_f..high.to_f) if low.present? && high.present?
   }
 
+  validate :payment_reference_must_change, if: :payment_reference_present_in_params?
+
+  attr_accessor :payment_reference_in_params
+
   def self.search(params = {})
     sort_column = params[:sort].presence_in(%w[invoice_number status affiliation]) || 'id'
     sort_direction = params[:direction].presence_in(%w[asc desc]) || 'desc'
@@ -61,6 +65,10 @@ def billing_system?
     initiator == BILLING_SYSTEM
   end
 
+  def fully_paid?(amount)
+    amount.to_f >= transaction_amount.to_f
+  end
+
   def to_h
     {
       invoice_number:,
@@ -74,4 +82,16 @@ def to_h
       sent_at_omniva:
     }
   end
+
+  private
+
+  def payment_reference_present_in_params?
+    payment_reference_in_params
+  end
+
+  def payment_reference_must_change
+    return unless payment_reference.present? && payment_reference == payment_reference_was
+
+    errors.add(:payment_reference, 'must be different from the existing payment reference')
+  end
 end
diff --git a/app/services/notify.rb b/app/services/notify.rb
index 623ff82..f942dba 100644
--- a/app/services/notify.rb
+++ b/app/services/notify.rb
@@ -29,8 +29,8 @@ def self.call(response:)
     end
     return if invoice.paid?
 
-    notifier.update_invoice_state(parsed_response:, invoice:)
-    return unless invoice.paid?
+    return unless notifier.update_invoice_state(parsed_response:, invoice:)
+    return if !invoice.paid? && !invoice.partially_paid?
     return if invoice.billing_system?
 
     url = notifier.get_update_payment_url[invoice.initiator.to_sym]
@@ -68,12 +68,21 @@ def notify(title:, error_message:)
   end
 
   def update_invoice_state(parsed_response:, invoice:)
-    status = parsed_response[:payment_state] == SETTLED ? :paid : :failed
+    paid_status = invoice.fully_paid?(parsed_response[:initial_amount]) ? :paid : :partially_paid
+    status = parsed_response[:payment_state] == SETTLED ? paid_status : :failed
 
-    invoice.update(payment_reference: parsed_response[:payment_reference],
-                   status:,
-                   transaction_time: parsed_response[:transaction_time],
-                   everypay_response: parsed_response)
+    invoice.payment_reference_in_params = parsed_response.key?(:payment_reference)
+    invoice.assign_attributes(
+      payment_reference: parsed_response[:payment_reference],
+      status:,
+      transaction_time: parsed_response[:transaction_time],
+      everypay_response: parsed_response
+    )
+
+    return true if invoice.save
+
+    Rails.logger.info("Error saving invoice #{invoice.invoice_number}: #{invoice.errors.full_messages.to_sentence}")
+    false
   end
 
   def invoice_numbers_from_multi_payment(invoice)
diff --git a/app/services/oneoff.rb b/app/services/oneoff.rb
index 1191278..837c454 100644
--- a/app/services/oneoff.rb
+++ b/app/services/oneoff.rb
@@ -4,22 +4,24 @@ class Oneoff
   include Request
   include ApplicationService
 
-  attr_reader :invoice_number, :customer_url, :reference_number, :bulk, :bulk_invoices
+  attr_reader :invoice_number, :customer_url, :reference_number, :amount, :bulk, :bulk_invoices
 
-  def initialize(invoice_number:, customer_url:, reference_number:, bulk: false, bulk_invoices: [])
+  def initialize(invoice_number:, customer_url:, reference_number:, amount: nil, bulk: false, bulk_invoices: [])
     @invoice = Invoice.find_by(invoice_number: invoice_number)
 
     @invoice_number = invoice_number
     @customer_url = customer_url
     @reference_number = reference_number
+    @amount = amount
     @bulk = bulk
     @bulk_invoices = bulk_invoices
   end
 
-  def self.call(invoice_number:, customer_url:, reference_number:, bulk: false, bulk_invoices: [])
+  def self.call(invoice_number:, customer_url:, reference_number:, amount: nil, bulk: false, bulk_invoices: [])
     new(invoice_number: invoice_number,
         customer_url: customer_url,
         reference_number: reference_number,
+        amount: amount,
         bulk: bulk,
         bulk_invoices: bulk_invoices).call
   end
@@ -52,6 +54,7 @@ def call
 
   def base_request
     uri = URI("#{GlobalVariable::BASE_ENDPOINT}#{GlobalVariable::ONEOFF_ENDPOINT}")
+
     post(direction: 'everypay', path: uri, params: body)
   end
 
@@ -61,12 +64,12 @@ def body
     {
       'api_username' => GlobalVariable::API_USERNAME,
       'account_name' => GlobalVariable::ACCOUNT_NAME,
-      'amount' => @invoice.transaction_amount.to_f,
+      'amount' => amount ? amount.to_f : @invoice.transaction_amount.to_f,
       'order_reference' => bulk ? bulk_description.to_s : @invoice.invoice_number.to_s,
       # 'token_agreement' => 'unscheduled',
       'request_token' => false,
-      'nonce' => "#{rand(10 ** 30).to_s.rjust(30,'0')}",
-      'timestamp' => "#{Time.zone.now.to_formatted_s(:iso8601)}",
+      'nonce' => rand(10**30).to_s.rjust(30, '0'),
+      'timestamp' => Time.zone.now.to_formatted_s(:iso8601),
       'customer_url' => customer_url,
       'preferred_country' => 'EE',
       'locale' => 'en',
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index 607fe95..5324345 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -69,6 +69,7 @@
 
   config.before(:each) do
     DatabaseCleaner.strategy = :transaction
+    allow(Rails.logger).to receive(:info)
   end
 
   config.before(:each, :js => true) do
diff --git a/spec/requests/api/v1/invoice_generator/oneoff_spec.rb b/spec/requests/api/v1/invoice_generator/oneoff_spec.rb
index 5d9c39d..f857c52 100644
--- a/spec/requests/api/v1/invoice_generator/oneoff_spec.rb
+++ b/spec/requests/api/v1/invoice_generator/oneoff_spec.rb
@@ -18,7 +18,7 @@
         .to_return(status: 200, body: payment_link.to_json, headers: {})
     end
 
-    it 'should return the payment link if intiiator is eeid' do
+    it 'should return the payment link if initiator is eeid' do
       payload = {
         invoice_number: invoice.invoice_number,
         customer_url: customer_url_eeid,
diff --git a/spec/services/notify_spec.rb b/spec/services/notify_spec.rb
index 2ccbebc..8e2101c 100644
--- a/spec/services/notify_spec.rb
+++ b/spec/services/notify_spec.rb
@@ -32,7 +32,8 @@
         payment_state: 'settled',
         transaction_time: Time.zone.now - 1.hour,
         order_reference: invoice.invoice_number.to_s,
-        payment_reference: 'test'
+        payment_reference: 'test',
+        initial_amount: invoice.transaction_amount
       }
 
       Notify.call(response: JSON.parse(everypay_response.to_json))
@@ -63,7 +64,8 @@
         payment_state: 'settled',
         transaction_time: Time.zone.now - 1.hour,
         order_reference: "ref:#{invoice_three.invoice_number}, #{invoice_three.description.split(' ').join(', ')}",
-        payment_reference: 'test'
+        payment_reference: 'test',
+        initial_amount: invoice_three.transaction_amount
       }
 
       Notify.call(response: JSON.parse(everypay_response.to_json))
@@ -78,6 +80,51 @@
     end
   end
 
+  describe 'partial payment process' do
+    let(:everypay_response) do 
+      {
+        payment_state: 'settled',
+        transaction_time: Time.zone.now - 1.hour,
+        order_reference: invoice.invoice_number.to_s,
+        payment_reference: 'test',
+        initial_amount: invoice.transaction_amount.to_f - 1
+      }
+    end
+
+    it 'should mark single invoice as partially_paid if settled and not fully paid' do
+      invoice.initiator = 'auction'
+      invoice.invoice_number = 3
+      invoice.save
+      expect(invoice.initiator).to eq('auction')
+      expect(invoice.status).to eq('unpaid')
+
+      Notify.call(response: JSON.parse(everypay_response.to_json))
+      invoice.reload
+
+      expect(invoice.status).to eq('partially_paid')
+      
+    end
+
+    it 'should not update invoice state if payment_reference is the same' do
+      invoice.save
+      expect(invoice.status).to eq('unpaid')
+
+      Notify.call(response: JSON.parse(everypay_response.to_json))
+      invoice.reload
+
+      expect(invoice.status).to eq('partially_paid')
+      expect(invoice.payment_reference).to eq('test')
+      updated_at = invoice.updated_at
+
+      Notify.call(response: JSON.parse(everypay_response.to_json))
+
+      expect(Rails.logger).to have_received(:info).with(
+        "Error saving invoice #{invoice.invoice_number}: Payment reference must be different from the existing payment reference"
+      )
+      expect(invoice.updated_at).to eq(updated_at)
+    end
+  end
+
   describe 'email notifier' do
     let!(:admin) { create(:user) }
 
@@ -116,7 +163,8 @@
         payment_state: 'settled',
         transaction_time: Time.zone.now - 1.hour,
         order_reference: invoice.invoice_number.to_s,
-        payment_reference: 'test'
+        payment_reference: 'test',
+        initial_amount: invoice.transaction_amount
       }
 
       response = Notify.call(response: JSON.parse(everypay_response.to_json))
diff --git a/spec/services/oneoff_spec.rb b/spec/services/oneoff_spec.rb
index 3e29ceb..0047fc9 100644
--- a/spec/services/oneoff_spec.rb
+++ b/spec/services/oneoff_spec.rb
@@ -1,4 +1,6 @@
 RSpec.describe Oneoff do
+  payment_link = { 'payment_link' => 'https://everypay.ee' }
+
   describe 'successful case' do
     let(:invoice) { create(:invoice) }
     let(:customer_url_registry) { GlobalVariable::BASE_REGISTRY }
@@ -7,8 +9,6 @@
     let(:customer_url_auction) { GlobalVariable::BASE_AUCTION }
     let(:reference) { create(:reference) }
 
-    payment_link = { 'payment_link' => 'https://everypay.ee' }
-
     before(:each) do
       stub_request(:post, "#{GlobalVariable::BASE_ENDPOINT}#{GlobalVariable::ONEOFF_ENDPOINT}")
         .to_return(status: 200, body: payment_link.to_json, headers: {})
@@ -50,6 +50,25 @@
     end
   end
 
+  describe 'with custom amount' do
+    let(:invoice) { create(:invoice) }
+    let(:customer_url_auction) { GlobalVariable::BASE_AUCTION }
+
+    before do
+      stub_request(:post, "#{GlobalVariable::BASE_ENDPOINT}#{GlobalVariable::ONEOFF_ENDPOINT}")
+        .with(body: /"amount":100.0/)
+        .to_return(status: 200, body: payment_link.to_json, headers: {})
+    end
+
+    it 'should generate oneoff link for auction' do
+      response = described_class.call(invoice_number: invoice.invoice_number.to_s,
+                                      customer_url: customer_url_auction,
+                                      reference_number: nil,
+                                      amount: 100)
+      expect(response.instance).to a_hash_including(payment_link)
+    end
+  end
+
   describe 'invalid case' do
     let(:invoice) { create(:invoice) }