diff --git a/README.md b/README.md
index 4b952790..8334aaab 100644
--- a/README.md
+++ b/README.md
@@ -60,6 +60,25 @@ Reminder emails are sent to pending signers on a configurable schedule.
 - Deduplication guard prevents the same reminder from being sent twice within 1 minute
 - Job scheduling handles container restarts gracefully (clears stale scheduled jobs before re-registering)
 
+## Paperless-ngx Integration
+
+Automatically upload completed, fully-signed documents to a [paperless-ngx](https://docs.paperless-ngx.com/) instance for archival and full-text search.
+
+**How it works:**
+- When all parties have signed a submission, the combined result PDF and audit trail are uploaded to paperless-ngx via its REST API.
+- If the combined PDF feature is not enabled, individual per-submitter result PDFs are uploaded instead.
+- Documents are titled `"Template Name - Signer 1, Signer 2"` with the signing completion date.
+- Uploads run as a background job with exponential retry (up to 10 attempts) — they never block the signing flow.
+
+**Configuration (env vars only — no GUI):**
+
+| Variable | Description |
+|----------|-------------|
+| `PAPERLESS_NGX_URL` | Base URL of your paperless-ngx instance (e.g., `http://paperless:8000`) |
+| `PAPERLESS_NGX_TOKEN` | API token for authentication ([how to get one](https://docs.paperless-ngx.com/api/#authorization)) |
+
+The feature is inactive unless both variables are set.
+
 ## What's NOT included
 
 These Pro features remain unavailable in this fork (they require significant UI/infrastructure work):
diff --git a/app/jobs/process_submitter_completion_job.rb b/app/jobs/process_submitter_completion_job.rb
index 135c0c38..27a65448 100644
--- a/app/jobs/process_submitter_completion_job.rb
+++ b/app/jobs/process_submitter_completion_job.rb
@@ -20,6 +20,10 @@ class ProcessSubmitterCompletionJob
       Submissions::EnsureAuditGenerated.call(submitter.submission)
 
       enqueue_completed_emails(submitter)
+
+      if Submissions::UploadToPaperless.configured?
+        UploadToPaperlessJob.perform_async('submission_id' => submitter.submission_id)
+      end
     end
 
     create_completed_documents!(submitter)
diff --git a/app/jobs/upload_to_paperless_job.rb b/app/jobs/upload_to_paperless_job.rb
new file mode 100644
index 00000000..37847054
--- /dev/null
+++ b/app/jobs/upload_to_paperless_job.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class UploadToPaperlessJob
+  include Sidekiq::Job
+
+  sidekiq_options queue: :integrations
+
+  MAX_ATTEMPTS = 10
+
+  def perform(params = {})
+    return unless Submissions::UploadToPaperless.configured?
+
+    submission = Submission.find_by(id: params['submission_id'])
+
+    return unless submission
+
+    attempt = params['attempt'].to_i
+
+    Submissions::UploadToPaperless.call(submission)
+  rescue Submissions::UploadToPaperless::UploadError, Faraday::Error => e
+    return if attempt >= MAX_ATTEMPTS
+
+    Rails.logger.warn("Paperless-ngx upload failed (attempt #{attempt}): #{e.message}")
+
+    UploadToPaperlessJob.perform_in(
+      (2**attempt).minutes,
+      'submission_id' => params['submission_id'],
+      'attempt' => attempt + 1
+    )
+  end
+end
diff --git a/config/sidekiq.yml b/config/sidekiq.yml
index 01ba85a5..64a57588 100644
--- a/config/sidekiq.yml
+++ b/config/sidekiq.yml
@@ -4,6 +4,7 @@ queues:
   - [sms, 2]
   - [images, 1]
   - [mailers, 1]
+  - [integrations, 1]
   - [recurrent, 1]
   - [rollbar, 1]
 
diff --git a/docker-compose.e2e.yml b/docker-compose.e2e.yml
new file mode 100644
index 00000000..7f7b935a
--- /dev/null
+++ b/docker-compose.e2e.yml
@@ -0,0 +1,59 @@
+services:
+  rspec:
+    build:
+      context: .
+      dockerfile: Dockerfile.ci
+    command: sh -c "bundle exec rake db:create db:migrate && bundle exec rake assets:precompile && bundle exec rspec spec/integration"
+    depends_on:
+      postgres:
+        condition: service_healthy
+      paperless-ngx:
+        condition: service_healthy
+    environment:
+      RAILS_ENV: test
+      NODE_ENV: test
+      DATABASE_URL: postgres://postgres:postgres@postgres:5432/docuseal_test
+      PAPERLESS_NGX_URL: http://paperless-ngx:8000
+      PAPERLESS_NGX_TOKEN: ""
+
+  postgres:
+    image: postgres:18
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_DB: docuseal_test
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U postgres"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+    tmpfs:
+      - /var/lib/postgresql
+
+  paperless-redis:
+    image: docker.io/library/redis:8
+    tmpfs:
+      - /data
+
+  paperless-ngx:
+    image: ghcr.io/paperless-ngx/paperless-ngx:latest
+    depends_on:
+      - paperless-redis
+    ports:
+      - "8000:8000"
+    environment:
+      PAPERLESS_REDIS: redis://paperless-redis:6379
+      PAPERLESS_SECRET_KEY: test-secret-for-e2e-testing
+      PAPERLESS_ADMIN_USER: admin
+      PAPERLESS_ADMIN_PASSWORD: admin
+      PAPERLESS_ADMIN_MAIL: admin@test.local
+      PAPERLESS_TIME_ZONE: UTC
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8000"]
+      interval: 10s
+      timeout: 10s
+      retries: 10
+      start_period: 30s
+    tmpfs:
+      - /usr/src/paperless/data
+      - /usr/src/paperless/media
diff --git a/lib/submissions/upload_to_paperless.rb b/lib/submissions/upload_to_paperless.rb
new file mode 100644
index 00000000..6cc0ed83
--- /dev/null
+++ b/lib/submissions/upload_to_paperless.rb
@@ -0,0 +1,129 @@
+# frozen_string_literal: true
+
+module Submissions
+  module UploadToPaperless
+    UploadError = Class.new(StandardError)
+
+    BOUNDARY_PREFIX = '----DocuSealPaperlessUpload'
+
+    module_function
+
+    def call(submission)
+      return unless configured?
+
+      submission.submitters.load unless submission.submitters.loaded?
+
+      title = build_title(submission)
+      created = completed_date(submission)
+      results = documents_to_upload(submission, title).map do |attachment, doc_title|
+        upload_document(attachment, title: doc_title, created:)
+      end
+
+      results.compact.presence
+    end
+
+    def configured?
+      ENV['PAPERLESS_NGX_URL'].present? && ENV['PAPERLESS_NGX_TOKEN'].present?
+    end
+
+    def documents_to_upload(submission, title)
+      documents = []
+
+      if submission.combined_document.attached?
+        documents << [submission.combined_document, title]
+      else
+        submission.submitters.select(&:completed_at?).each do |submitter|
+          submitter.documents.each do |doc|
+            documents << [doc, title]
+          end
+        end
+      end
+
+      documents << [submission.audit_trail, "#{title} - Audit Trail"] if submission.audit_trail.attached?
+
+      documents
+    end
+
+    def build_title(submission)
+      submitter_names = submission.submitters
+                                  .select(&:completed_at?)
+                                  .sort_by(&:completed_at)
+                                  .filter_map(&:name)
+                                  .join(', ')
+
+      template_name = submission.template&.name || 'Document'
+
+      if submitter_names.present?
+        "#{template_name} - #{submitter_names}"
+      else
+        template_name
+      end
+    end
+
+    def completed_date(submission)
+      last_completed = submission.submitters.filter_map(&:completed_at).max
+      last_completed&.strftime('%Y-%m-%d')
+    end
+
+    def upload_document(attachment, title:, created:)
+      blob = attachment.blob
+      filename = sanitize_filename(blob.filename.to_s)
+      boundary = "#{BOUNDARY_PREFIX}#{SecureRandom.hex(16)}"
+
+      blob.open do |tempfile|
+        body = build_multipart_body(tempfile, filename:, title:, created:, boundary:)
+
+        response = connection.post('/api/documents/post_document/') do |req|
+          req.headers['Authorization'] = "Token #{ENV['PAPERLESS_NGX_TOKEN']}" # rubocop:disable Style/FetchEnvVar
+          req.headers['Content-Type'] = "multipart/form-data; boundary=#{boundary}"
+          req.body = body
+          req.options.read_timeout = 30
+          req.options.open_timeout = 10
+        end
+
+        if response.status >= 400
+          body_preview = response.body.to_s.truncate(200)
+          raise UploadError, "Paperless-ngx upload failed (HTTP #{response.status}): #{body_preview}"
+        end
+
+        response.body.to_s.delete('"').strip
+      end
+    end
+
+    def sanitize_filename(filename)
+      filename.gsub(/["\r\n\\]/, '_')
+    end
+
+    def build_multipart_body(tempfile, filename:, title:, created:, boundary:)
+      parts = []
+
+      parts << "--#{boundary}\r\n"
+      parts << "Content-Disposition: form-data; name=\"document\"; filename=\"#{filename}\"\r\n"
+      parts << "Content-Type: application/pdf\r\n\r\n"
+      parts << tempfile.read
+      parts << "\r\n"
+
+      parts << "--#{boundary}\r\n"
+      parts << "Content-Disposition: form-data; name=\"title\"\r\n\r\n"
+      parts << title
+      parts << "\r\n"
+
+      if created
+        parts << "--#{boundary}\r\n"
+        parts << "Content-Disposition: form-data; name=\"created\"\r\n\r\n"
+        parts << created
+        parts << "\r\n"
+      end
+
+      parts << "--#{boundary}--\r\n"
+
+      parts.join
+    end
+
+    def connection
+      Faraday.new(url: ENV['PAPERLESS_NGX_URL']) do |f| # rubocop:disable Style/FetchEnvVar
+        f.adapter Faraday.default_adapter
+      end
+    end
+  end
+end
diff --git a/spec/integration/paperless_ngx_upload_spec.rb b/spec/integration/paperless_ngx_upload_spec.rb
new file mode 100644
index 00000000..390f4d34
--- /dev/null
+++ b/spec/integration/paperless_ngx_upload_spec.rb
@@ -0,0 +1,97 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+# rubocop:disable RSpec/DescribeClass, RSpec/InstanceVariable, RSpec/ExpectInHook
+
+# Run with: docker compose -f docker-compose.e2e.yml up
+# This spec requires a running paperless-ngx instance.
+# It acquires a token from paperless-ngx, uploads a document, and verifies it was received.
+RSpec.describe 'Paperless-ngx document upload', type: :integration do
+  let(:paperless_url) { ENV.fetch('PAPERLESS_NGX_URL', 'http://paperless-ngx:8000') }
+  let(:account) { create(:account) }
+  let(:user) { create(:user, account:) }
+  let(:template) { create(:template, account:, author: user, name: 'Integration Test Contract') }
+  let(:submission) { create(:submission, :with_submitters, template:, created_by_user: user) }
+
+  # Generate a unique PDF per test by appending a random trailer comment.
+  # This ensures paperless-ngx does not deduplicate uploads across tests.
+  def unique_pdf_io
+    base_pdf = Rails.root.join('spec/fixtures/sample-document.pdf').binread
+    unique_pdf = base_pdf + "\n% #{SecureRandom.uuid}\n"
+    StringIO.new(unique_pdf)
+  end
+
+  before do
+    # Skip if paperless-ngx is not reachable
+    WebMock.allow_net_connect!
+
+    begin
+      health = Faraday.get("#{paperless_url}/api/") { |req| req.options.open_timeout = 5 }
+      skip "Paperless-ngx not available (HTTP #{health.status})" unless health.status < 400
+    rescue Faraday::Error
+      skip 'Paperless-ngx not available (connection failed)'
+    end
+
+    # Acquire a token from paperless-ngx
+    token_response = Faraday.post("#{paperless_url}/api/token/") do |req|
+      req.headers['Content-Type'] = 'application/json'
+      req.body = { username: 'admin', password: 'admin' }.to_json
+    end
+
+    expect(token_response.status).to eq(200), "Failed to get paperless-ngx token: #{token_response.body}"
+    @paperless_token = JSON.parse(token_response.body)['token']
+
+    # Configure ENV for the upload module
+    allow(ENV).to receive(:fetch).and_call_original
+    allow(ENV).to receive(:[]).and_call_original
+    allow(ENV).to receive(:[]).with('PAPERLESS_NGX_URL').and_return(paperless_url)
+    allow(ENV).to receive(:[]).with('PAPERLESS_NGX_TOKEN').and_return(@paperless_token)
+
+    # Mark all submitters as completed
+    submission.submitters.each_with_index do |submitter, i|
+      submitter.update!(completed_at: i.hours.ago, name: "Test Signer #{i + 1}")
+    end
+
+    # Attach a combined document with unique content per test
+    blob = ActiveStorage::Blob.create_and_upload!(
+      io: unique_pdf_io,
+      filename: "integration-test-#{SecureRandom.hex(4)}.pdf",
+      content_type: 'application/pdf'
+    )
+    ActiveStorage::Attachment.create!(blob:, name: 'combined_document', record: submission)
+  end
+
+  after do
+    WebMock.disable_net_connect!(allow_localhost: true)
+  end
+
+  it 'uploads a signed document to paperless-ngx and receives a task UUID' do
+    result = Submissions::UploadToPaperless.call(submission)
+
+    expect(result).to be_present
+    expect(result.first).to match(/\A[0-9a-f-]+\z/)
+  end
+
+  it 'uploads via the background job without error' do
+    expect do
+      UploadToPaperlessJob.new.perform('submission_id' => submission.id)
+    end.not_to raise_error
+  end
+
+  it 'document is consumable by paperless-ngx' do
+    result = Submissions::UploadToPaperless.call(submission)
+    task_id = result.first
+
+    # Poll the tasks API to verify consumption started
+    response = Faraday.get("#{paperless_url}/api/tasks/?task_id=#{task_id}") do |req|
+      req.headers['Authorization'] = "Token #{@paperless_token}"
+    end
+
+    expect(response.status).to eq(200)
+    tasks = JSON.parse(response.body)
+    expect(tasks).to be_present
+  end
+end
+
+# rubocop:enable RSpec/DescribeClass, RSpec/InstanceVariable, RSpec/ExpectInHook
diff --git a/spec/jobs/upload_to_paperless_job_spec.rb b/spec/jobs/upload_to_paperless_job_spec.rb
new file mode 100644
index 00000000..51ea789b
--- /dev/null
+++ b/spec/jobs/upload_to_paperless_job_spec.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe UploadToPaperlessJob do
+  let(:account) { create(:account) }
+  let(:user) { create(:user, account:) }
+  let(:template) { create(:template, account:, author: user) }
+  let(:submission) { create(:submission, :with_submitters, template:, created_by_user: user) }
+
+  let(:paperless_url) { 'http://paperless:8000' }
+  let(:paperless_token) { 'test-token-abc123' }
+
+  before do
+    submission.submitters.each_with_index do |submitter, i|
+      submitter.update!(completed_at: i.hours.ago, name: "Signer #{i + 1}")
+    end
+
+    allow(ENV).to receive(:fetch).and_call_original
+    allow(ENV).to receive(:[]).and_call_original
+    allow(ENV).to receive(:[]).with('PAPERLESS_NGX_URL').and_return(paperless_url)
+    allow(ENV).to receive(:[]).with('PAPERLESS_NGX_TOKEN').and_return(paperless_token)
+
+    stub_request(:post, "#{paperless_url}/api/documents/post_document/")
+      .to_return(status: 200, body: '"task-uuid-123"')
+  end
+
+  describe '#perform' do
+    context 'when paperless-ngx is configured' do
+      before do
+        blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'combined-result.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob:, name: 'combined_document', record: submission)
+      end
+
+      it 'uploads documents to paperless-ngx' do
+        described_class.new.perform('submission_id' => submission.id)
+
+        expect(WebMock).to have_requested(:post, "#{paperless_url}/api/documents/post_document/")
+          .at_least_once
+      end
+    end
+
+    context 'when paperless-ngx is not configured' do
+      before do
+        allow(ENV).to receive(:[]).with('PAPERLESS_NGX_URL').and_return(nil)
+        allow(ENV).to receive(:[]).with('PAPERLESS_NGX_TOKEN').and_return(nil)
+      end
+
+      it 'does nothing' do
+        described_class.new.perform('submission_id' => submission.id)
+
+        expect(WebMock).not_to have_requested(:post, /paperless/)
+      end
+    end
+
+    context 'when submission does not exist' do
+      it 'does nothing' do
+        described_class.new.perform('submission_id' => -1)
+
+        expect(WebMock).not_to have_requested(:post, /paperless/)
+      end
+    end
+
+    context 'when upload fails with a retryable error' do
+      before do
+        stub_request(:post, "#{paperless_url}/api/documents/post_document/")
+          .to_return(status: 500, body: 'Internal Server Error')
+
+        blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'combined-result.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob:, name: 'combined_document', record: submission)
+      end
+
+      it 'enqueues a retry with incremented attempt' do
+        expect do
+          described_class.new.perform('submission_id' => submission.id, 'attempt' => 0)
+        end.to change(described_class.jobs, :size).by(1)
+
+        args = described_class.jobs.last['args'].first
+        expect(args['attempt']).to eq(1)
+        expect(args['submission_id']).to eq(submission.id)
+      end
+    end
+
+    context 'when max attempts is reached' do
+      before do
+        stub_request(:post, "#{paperless_url}/api/documents/post_document/")
+          .to_return(status: 500, body: 'Internal Server Error')
+
+        blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'combined-result.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob:, name: 'combined_document', record: submission)
+      end
+
+      it 'does not enqueue another retry' do
+        expect do
+          described_class.new.perform('submission_id' => submission.id, 'attempt' => 11)
+        end.not_to change(described_class.jobs, :size)
+      end
+    end
+  end
+end
diff --git a/spec/lib/submissions/upload_to_paperless_spec.rb b/spec/lib/submissions/upload_to_paperless_spec.rb
new file mode 100644
index 00000000..1dcd49b4
--- /dev/null
+++ b/spec/lib/submissions/upload_to_paperless_spec.rb
@@ -0,0 +1,208 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Submissions::UploadToPaperless do
+  let(:account) { create(:account) }
+  let(:user) { create(:user, account:) }
+  let(:template) { create(:template, account:, author: user, name: 'Employment Contract') }
+  let(:submission) { create(:submission, :with_submitters, template:, created_by_user: user) }
+
+  let(:paperless_url) { 'http://paperless:8000' }
+  let(:paperless_token) { 'test-token-abc123' }
+
+  before do
+    submission.submitters.each_with_index do |submitter, i|
+      submitter.update!(completed_at: i.hours.ago, name: "Signer #{i + 1}")
+    end
+
+    allow(ENV).to receive(:fetch).and_call_original
+    allow(ENV).to receive(:[]).and_call_original
+    allow(ENV).to receive(:[]).with('PAPERLESS_NGX_URL').and_return(paperless_url)
+    allow(ENV).to receive(:[]).with('PAPERLESS_NGX_TOKEN').and_return(paperless_token)
+
+    stub_request(:post, "#{paperless_url}/api/documents/post_document/")
+      .to_return(status: 200, body: '"550e8400-e29b-41d4-a716-446655440000"')
+  end
+
+  describe '.call' do
+    context 'when submission has a combined document' do
+      before do
+        blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'combined-result.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob:, name: 'combined_document', record: submission)
+      end
+
+      it 'uploads the combined document to paperless-ngx' do
+        described_class.call(submission)
+
+        expect(WebMock).to have_requested(:post, "#{paperless_url}/api/documents/post_document/")
+          .with(headers: { 'Authorization' => "Token #{paperless_token}" })
+          .once
+      end
+
+      it 'sends the correct title with template name and submitter names' do
+        described_class.call(submission)
+
+        expect(WebMock).to(have_requested(:post, "#{paperless_url}/api/documents/post_document/")
+          .with { |req| req.body.include?('Employment Contract') && req.body.include?('Signer') })
+      end
+
+      it 'sends the created date' do
+        described_class.call(submission)
+
+        expect(WebMock).to(have_requested(:post, "#{paperless_url}/api/documents/post_document/")
+          .with { |req| req.body.include?('created') })
+      end
+
+      it 'returns the task UUIDs from paperless-ngx' do
+        result = described_class.call(submission)
+
+        expect(result).to include('550e8400-e29b-41d4-a716-446655440000')
+      end
+    end
+
+    context 'when submission has an audit trail' do
+      before do
+        blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'audit-trail.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob:, name: 'audit_trail', record: submission)
+      end
+
+      it 'uploads the audit trail to paperless-ngx' do
+        described_class.call(submission)
+
+        expect(WebMock).to(have_requested(:post, "#{paperless_url}/api/documents/post_document/")
+          .with { |req| req.body.include?('Audit') }
+          .once)
+      end
+    end
+
+    context 'when submission has both combined document and audit trail' do
+      before do
+        combined_blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'combined-result.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob: combined_blob, name: 'combined_document', record: submission)
+
+        audit_blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'audit-trail.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob: audit_blob, name: 'audit_trail', record: submission)
+      end
+
+      it 'uploads both documents to paperless-ngx' do
+        described_class.call(submission)
+
+        expect(WebMock).to have_requested(:post, "#{paperless_url}/api/documents/post_document/").twice
+      end
+    end
+
+    context 'when submission has no combined document but has submitter documents' do
+      before do
+        submitter = submission.submitters.first
+        blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'signed-result.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob:, name: 'documents', record: submitter)
+      end
+
+      it 'uploads the submitter documents to paperless-ngx' do
+        described_class.call(submission)
+
+        expect(WebMock).to have_requested(:post, "#{paperless_url}/api/documents/post_document/")
+          .at_least_once
+      end
+    end
+
+    context 'when paperless-ngx env vars are not configured' do
+      before do
+        allow(ENV).to receive(:[]).with('PAPERLESS_NGX_URL').and_return(nil)
+        allow(ENV).to receive(:[]).with('PAPERLESS_NGX_TOKEN').and_return(nil)
+      end
+
+      it 'does nothing and returns nil' do
+        result = described_class.call(submission)
+
+        expect(result).to be_nil
+        expect(WebMock).not_to have_requested(:post, /paperless/)
+      end
+    end
+
+    context 'when paperless-ngx returns an error' do
+      before do
+        stub_request(:post, "#{paperless_url}/api/documents/post_document/")
+          .to_return(status: 500, body: 'Internal Server Error')
+
+        blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'combined-result.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob:, name: 'combined_document', record: submission)
+      end
+
+      it 'raises an UploadError' do
+        expect { described_class.call(submission) }.to raise_error(Submissions::UploadToPaperless::UploadError)
+      end
+    end
+
+    context 'when paperless-ngx connection fails' do
+      before do
+        stub_request(:post, "#{paperless_url}/api/documents/post_document/")
+          .to_timeout
+
+        blob = ActiveStorage::Blob.create_and_upload!(
+          io: Rails.root.join('spec/fixtures/sample-document.pdf').open,
+          filename: 'combined-result.pdf',
+          content_type: 'application/pdf'
+        )
+        ActiveStorage::Attachment.create!(blob:, name: 'combined_document', record: submission)
+      end
+
+      it 'raises a connection error' do
+        expect { described_class.call(submission) }.to raise_error(Faraday::ConnectionFailed)
+      end
+    end
+  end
+
+  describe '.configured?' do
+    context 'when both env vars are set' do
+      it 'returns true' do
+        expect(described_class.configured?).to be true
+      end
+    end
+
+    context 'when URL is missing' do
+      before do
+        allow(ENV).to receive(:[]).with('PAPERLESS_NGX_URL').and_return(nil)
+      end
+
+      it 'returns false' do
+        expect(described_class.configured?).to be false
+      end
+    end
+
+    context 'when token is missing' do
+      before do
+        allow(ENV).to receive(:[]).with('PAPERLESS_NGX_TOKEN').and_return(nil)
+      end
+
+      it 'returns false' do
+        expect(described_class.configured?).to be false
+      end
+    end
+  end
+end