diff --git a/backend/spec/requests/post_imports_spec.rb b/backend/spec/requests/post_imports_spec.rb
new file mode 100644
index 0000000..b3c6ae8
--- /dev/null
+++ b/backend/spec/requests/post_imports_spec.rb
@@ -0,0 +1,112 @@
+require 'rails_helper'
+
+RSpec.describe 'Post imports API', type: :request do
+  let(:member) { create(:user, :member) }
+
+  before do
+    allow(Preview::UrlSafety).to receive(:validate) do |url|
+      [URI.parse(url), ['8.8.8.8']]
+    end
+    allow(PostMetadataFetcher).to receive(:fetch).and_return(
+      title: 'fetched title',
+      thumbnail_base: nil,
+      tags: ''
+    )
+  end
+
+  describe 'POST /posts/import/preview' do
+    it 'requires a member' do
+      sign_out
+      post '/posts/import/preview', params: { source: 'https://example.com/post' }
+      expect(response).to have_http_status(:unauthorized)
+
+      sign_in_as(create(:user, :guest))
+      post '/posts/import/preview', params: { source: 'https://example.com/post' }
+      expect(response).to have_http_status(:forbidden)
+    end
+
+    it 'parses a URL list and returns preview rows' do
+      sign_in_as(member)
+
+      post '/posts/import/preview', params: {
+        source: " https://example.com/one \r\n\r\nhttps://example.com/two"
+      }
+
+      expect(response).to have_http_status(:ok)
+      expect(json.fetch('rows').map { _1.fetch('source_row') }).to eq([1, 3])
+      expect(json.fetch('rows').map { _1.fetch('url') }).to eq([
+        'https://example.com/one',
+        'https://example.com/two'
+      ])
+    end
+
+    it 'returns a safe 400 response for an invalid source' do
+      sign_in_as(member)
+
+      post '/posts/import/preview', params: { source: '' }
+
+      expect(response).to have_http_status(:bad_request)
+      expect(json.fetch('message')).to eq('URL を入力してください．')
+    end
+  end
+
+  describe 'POST /posts/import/validate' do
+    it 'accepts camel-case row properties and returns their warnings' do
+      sign_in_as(member)
+
+      post '/posts/import/validate', params: {
+        rows: [{
+          sourceRow: '1',
+          url: 'https://example.com/post',
+          metadataUrl: 'https://example.com/post',
+          attributes: { title: 'manual title' },
+          provenance: { url: 'manual', title: 'manual' },
+          tagSources: { automatic: '', manual: '' },
+          fieldWarnings: { title: ['old warning'] },
+          baseWarnings: ['base warning']
+        }],
+        changed_row: -1
+      }
+
+      expect(response).to have_http_status(:ok)
+      result = json.fetch('rows').first
+      expect(result.fetch('source_row')).to eq(1)
+      expect(result.fetch('tag_sources')).to eq('automatic' => '', 'manual' => '')
+      expect(result.fetch('field_warnings')).to eq('title' => ['old warning'])
+      expect(result.fetch('base_warnings')).to eq(['base warning'])
+    end
+
+    it 'rejects a non-array rows value with 400' do
+      sign_in_as(member)
+
+      post '/posts/import/validate', params: { rows: { sourceRow: 1 }, changed_row: -1 }
+
+      expect(response).to have_http_status(:bad_request)
+      expect(json.fetch('message')).to eq('取込行の形式が不正です．')
+    end
+  end
+
+  describe 'POST /posts/import' do
+    it 'returns a formal skipped result for an existing post' do
+      existing = create(:post, url: 'https://example.com/existing')
+      sign_in_as(member)
+
+      post '/posts/import', params: {
+        rows: [{
+          sourceRow: 1,
+          url: existing.url,
+          attributes: { title: 'ignored' },
+          provenance: { url: 'manual', title: 'manual' },
+          tagSources: { automatic: '', manual: '' }
+        }]
+      }
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to include('created' => 0, 'skipped' => 1, 'failed' => 0)
+      expect(json.fetch('rows').first).to include(
+        'status' => 'skipped',
+        'existing_post_id' => existing.id
+      )
+    end
+  end
+end
diff --git a/backend/spec/services/post_import_previewer_spec.rb b/backend/spec/services/post_import_previewer_spec.rb
new file mode 100644
index 0000000..fc6e16b
--- /dev/null
+++ b/backend/spec/services/post_import_previewer_spec.rb
@@ -0,0 +1,187 @@
+require 'rails_helper'
+
+RSpec.describe PostImportPreviewer do
+  before do
+    allow(Preview::UrlSafety).to receive(:validate) do |url|
+      [URI.parse(url), ['8.8.8.8']]
+    end
+  end
+
+  def row(source_row:, url:, attributes: { }, provenance: { }, **values)
+    {
+      source_row:,
+      url:,
+      attributes:,
+      provenance:
+    }.merge(values)
+  end
+
+  describe '#preview_rows' do
+    it 'marks an existing post for skipping without fetching metadata' do
+      existing = create(:post, url: 'https://example.com/existing')
+      expect(PostMetadataFetcher).not_to receive(:fetch)
+
+      result = described_class.new.preview_rows(rows: [
+        row(source_row: 1, url: 'https://EXAMPLE.com/existing/')
+      ]).first
+
+      expect(result).to include(
+        url: 'https://example.com/existing',
+        skip_reason: 'existing',
+        existing_post_id: existing.id,
+        validation_errors: {}
+      )
+      expect(result.fetch(:field_warnings)).to eq({})
+    end
+
+    it 'reports list duplicates as URL errors instead of existing skips' do
+      create(:post, url: 'https://example.com/duplicate')
+      expect(PostMetadataFetcher).not_to receive(:fetch)
+
+      results = described_class.new.preview_rows(rows: [
+        row(source_row: 1, url: 'https://example.com/duplicate'),
+        row(source_row: 2, url: 'https://EXAMPLE.com/duplicate/')
+      ])
+
+      expect(results.map { _1[:validation_errors] }).to all(
+        include(url: ['URL が重複しています．'])
+      )
+      expect(results).to all(include(skip_reason: nil, existing_post_id: nil))
+    end
+
+    it 'does not fetch metadata for an unsafe URL' do
+      allow(Preview::UrlSafety).to receive(:validate)
+          .and_raise(Preview::UrlSafety::UnsafeUrl, '安全でない接続先は使用できません．')
+      expect(PostMetadataFetcher).not_to receive(:fetch)
+
+      result = described_class.new.preview_rows(rows: [
+        row(source_row: 1, url: 'https://unsafe.example/post')
+      ]).first
+
+      expect(result.fetch(:validation_errors)).to include(
+        url: ['安全でない接続先は使用できません．']
+      )
+    end
+
+    it 'applies metadata to automatic fields and recognises metadata tags' do
+      Tag.create!(name: 'known-tag', category: :general)
+      allow(PostMetadataFetcher).to receive(:fetch).and_return(
+        title: 'metadata title',
+        thumbnail_base: 'https://example.com/thumb.jpg',
+        duration: 2_000,
+        tags: 'known-tag'
+      )
+
+      result = described_class.new.preview_rows(rows: [
+        row(source_row: 1, url: 'https://example.com/new')
+      ]).first
+
+      expect(result.fetch(:attributes)).to include(
+        'title' => 'metadata title',
+        'thumbnail_base' => 'https://example.com/thumb.jpg',
+        'duration' => 2_000,
+        'tags' => 'known-tag'
+      )
+      expect(result.fetch(:field_warnings)).not_to have_key('tags')
+      expect(PostMetadataFetcher).to have_received(:fetch).once
+    end
+
+    it 'preserves manual empty values when metadata is available' do
+      allow(PostMetadataFetcher).to receive(:fetch).and_return(
+        title: 'metadata title',
+        tags: 'metadata-tag'
+      )
+
+      result = described_class.new.preview_rows(rows: [
+        row(
+          source_row: 1,
+          url: 'https://example.com/manual',
+          attributes: { title: '', tags: '' },
+          provenance: { title: 'manual', tags: 'manual' },
+          tag_sources: { automatic: 'old-tag', manual: '' }
+        )
+      ]).first
+
+      expect(result.fetch(:attributes)).to include('title' => '', 'tags' => '')
+      expect(result.fetch(:tag_sources)).to include('manual' => '')
+    end
+
+    it 'clears warnings derived from an old metadata URL' do
+      allow(PostMetadataFetcher).to receive(:fetch).and_return(
+        title: 'new title',
+        thumbnail_base: 'https://example.com/new-thumb.jpg',
+        tags: ''
+      )
+
+      result = described_class.new.preview_rows(rows: [
+        row(
+          source_row: 1,
+          url: 'https://example.com/new-url',
+          attributes: { title: 'old title', tags: 'old-tag' },
+          provenance: { title: 'automatic', tags: 'automatic' },
+          tag_sources: { automatic: 'old-tag', manual: '' },
+          metadata_url: 'https://example.com/old-url',
+          field_warnings: { tags: ['old tag warning'], url: ['old fetch warning'] },
+          base_warnings: ['old base warning']
+        )
+      ]).first
+
+      expect(result.fetch(:attributes)).to include('title' => 'new title', 'tags' => '')
+      expect(result.fetch(:base_warnings)).to eq([])
+      expect(result.fetch(:field_warnings).values.flatten)
+          .not_to include('old tag warning', 'old fetch warning')
+    end
+
+    it 'isolates an unexpected metadata failure to the affected URL' do
+      allow(PostMetadataFetcher).to receive(:fetch) do |url|
+        raise 'fetch failure' if url.include?('failure')
+
+        { title: 'successful title', tags: '' }
+      end
+      allow(Rails.logger).to receive(:error)
+
+      results = described_class.new.preview_rows(rows: [
+        row(source_row: 1, url: 'https://example.com/failure'),
+        row(source_row: 2, url: 'https://example.com/success')
+      ])
+
+      expect(results[0].fetch(:field_warnings)).to include(
+        'url' => [described_class::METADATA_FETCH_WARNING]
+      )
+      expect(results[1].fetch(:attributes)).to include('title' => 'successful title')
+    end
+
+    it 'turns an unsafe URL detected during metadata fetching into a URL error' do
+      allow(PostMetadataFetcher).to receive(:fetch)
+          .and_raise(Preview::UrlSafety::UnsafeUrl, '安全でない接続先です．')
+      allow(Rails.logger).to receive(:info)
+
+      result = described_class.new.preview_rows(rows: [
+        row(source_row: 1, url: 'https://example.com/redirects-to-private')
+      ]).first
+
+      expect(result.fetch(:validation_errors)).to include(
+        url: ['安全でない接続先です．']
+      )
+    end
+
+    it 'validates parent IDs from the preloaded set' do
+      parent = create(:post)
+
+      results = described_class.new.preview_rows(
+        rows: [
+          row(source_row: 1, url: 'https://example.com/valid-parent',
+              attributes: { parent_post_ids: parent.id.to_s }),
+          row(source_row: 2, url: 'https://example.com/missing-parent',
+              attributes: { parent_post_ids: '999999' })
+        ],
+        fetch_metadata: false
+      )
+
+      expect(results[0].fetch(:validation_errors)).not_to have_key(:parent_post_ids)
+      expect(results[1].fetch(:validation_errors)).to include(
+        parent_post_ids: ['存在しない親投稿 Id. があります．']
+      )
+    end
+  end
+end
diff --git a/backend/spec/services/post_import_row_normaliser_spec.rb b/backend/spec/services/post_import_row_normaliser_spec.rb
new file mode 100644
index 0000000..ec1a41c
--- /dev/null
+++ b/backend/spec/services/post_import_row_normaliser_spec.rb
@@ -0,0 +1,77 @@
+require 'rails_helper'
+
+RSpec.describe PostImportRowNormaliser do
+  def valid_row(overrides = { })
+    {
+      sourceRow: '1',
+      url: 'https://example.com/post',
+      metadataUrl: 'https://example.com/post',
+      attributes: { title: 'title', duration: 1_000 },
+      provenance: { url: 'manual', title: 'automatic' },
+      tagSources: { automatic: 'tag', manual: '' }
+    }.deep_merge(overrides)
+  end
+
+  describe '.normalise!' do
+    it 'normalises aliases and source rows into a permitted plain hash' do
+      row = ActionController::Parameters.new(valid_row)
+
+      expect(described_class.normalise!([row])).to eq([
+        {
+          'source_row' => 1,
+          'url' => 'https://example.com/post',
+          'metadata_url' => 'https://example.com/post',
+          'attributes' => { 'title' => 'title', 'duration' => 1_000 },
+          'provenance' => { 'url' => 'manual', 'title' => 'automatic' },
+          'tag_sources' => { 'automatic' => 'tag', 'manual' => '' }
+        }
+      ])
+    end
+
+    it 'normalises source rows before checking duplicates' do
+      rows = [valid_row, valid_row(sourceRow: 1, url: 'https://example.com/other')]
+
+      expect { described_class.normalise!(rows) }
+          .to raise_error(ArgumentError, '元行番号が重複しています．')
+    end
+
+    it 'rejects non-array batches and non-hash rows' do
+      expect { described_class.normalise!({}) }
+          .to raise_error(ArgumentError, '取込行の形式が不正です．')
+      expect { described_class.normalise!(['row']) }
+          .to raise_error(ArgumentError, '取込行の形式が不正です．')
+    end
+
+    it 'rejects unknown attributes and invalid field types' do
+      expect { described_class.normalise!([valid_row(attributes: { unknown: 'x' })]) }
+          .to raise_error(ArgumentError, '取込項目が不正です．')
+      expect { described_class.normalise!([valid_row(attributes: { title: [] })]) }
+          .to raise_error(ArgumentError, '取込項目の型が不正です．')
+      expect { described_class.normalise!([valid_row(attributes: { duration: false })]) }
+          .to raise_error(ArgumentError, '取込項目の型が不正です．')
+    end
+
+    it 'rejects unknown provenance and tag-source values' do
+      expect { described_class.normalise!([valid_row(provenance: { title: 'mapped' })]) }
+          .to raise_error(ArgumentError, '値の由来が不正です．')
+      expect { described_class.normalise!([valid_row(tagSources: { mapped: 'tag' })]) }
+          .to raise_error(ArgumentError, 'タグ由来の形式が不正です．')
+    end
+
+    it 'accepts warning fields only at the validation boundary' do
+      row = valid_row.merge(
+        fieldWarnings: { title: ['取得できませんでした．'] },
+        baseWarnings: ['確認してください．']
+      )
+
+      without_warnings = described_class.normalise!([row]).first
+      with_warnings = described_class.normalise!([row], allow_warning_fields: true).first
+
+      expect(without_warnings).not_to include('field_warnings', 'base_warnings')
+      expect(with_warnings).to include(
+        'field_warnings' => { 'title' => ['取得できませんでした．'] },
+        'base_warnings' => ['確認してください．']
+      )
+    end
+  end
+end
diff --git a/backend/spec/services/post_import_runner_spec.rb b/backend/spec/services/post_import_runner_spec.rb
new file mode 100644
index 0000000..235dabf
--- /dev/null
+++ b/backend/spec/services/post_import_runner_spec.rb
@@ -0,0 +1,133 @@
+require 'rails_helper'
+
+RSpec.describe PostImportRunner do
+  let(:actor) { create(:user, :member) }
+
+  def row(source_row: 1, url: 'https://example.com/post')
+    {
+      sourceRow: source_row,
+      url:,
+      attributes: { title: 'title', tags: '' },
+      provenance: { url: 'manual', title: 'manual', tags: 'manual' },
+      tagSources: { automatic: '', manual: '' }
+    }
+  end
+
+  def preview(source_row: 1, errors: { }, skip_reason: nil, existing_post_id: nil)
+    {
+      source_row:,
+      attributes: { 'title' => 'title', 'tags' => '' },
+      validation_errors: errors,
+      skip_reason:,
+      existing_post_id:
+    }
+  end
+
+  it 'previews the whole batch once before processing individual rows' do
+    rows = [row, row(source_row: 2, url: 'https://example.com/two')]
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    expect(previewer).to receive(:preview_rows)
+        .with(
+          rows: satisfy { _1.map { |row_value| row_value['source_row'] } == [1, 2] },
+          fetch_metadata: false
+        )
+        .and_return([preview, preview(source_row: 2)])
+    allow(PostCreator).to receive(:new).and_return(
+      instance_double(PostCreator, create!: create(:post))
+    )
+
+    result = described_class.new(actor:, rows:).run
+
+    expect(result).to include(created: 2, skipped: 0, failed: 0)
+  end
+
+  it 'treats validation errors as failures before an existing skip' do
+    existing = create(:post)
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([
+      preview(errors: { url: ['URL が重複しています．'] },
+              skip_reason: 'existing', existing_post_id: existing.id)
+    ])
+    expect(PostCreator).not_to receive(:new)
+
+    result = described_class.new(actor:, rows: [row]).run.fetch(:rows).first
+
+    expect(result).to include(
+      status: 'failed',
+      errors: { url: ['URL が重複しています．'] },
+      recoverable: true
+    )
+  end
+
+  it 'returns the existing post ID for skipped rows' do
+    existing = create(:post)
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([
+      preview(skip_reason: 'existing', existing_post_id: existing.id)
+    ])
+
+    result = described_class.new(actor:, rows: [row]).run.fetch(:rows).first
+
+    expect(result).to eq(
+      source_row: 1,
+      status: 'skipped',
+      existing_post_id: existing.id
+    )
+  end
+
+  it 'converts a URL uniqueness validation race into a skip' do
+    existing = create(:post, url: 'https://example.com/race')
+    invalid = Post.new(url: existing.url)
+    invalid.errors.add(:url, :taken)
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([preview])
+    creator = instance_double(PostCreator)
+    allow(PostCreator).to receive(:new).and_return(creator)
+    allow(creator).to receive(:create!).and_raise(ActiveRecord::RecordInvalid.new(invalid))
+
+    result = described_class.new(
+      actor:,
+      rows: [row(url: 'https://EXAMPLE.com/race/')]
+    ).run.fetch(:rows).first
+
+    expect(result).to include(status: 'skipped', existing_post_id: existing.id)
+  end
+
+  it 're-raises RecordNotUnique errors unrelated to the posts URL index' do
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([preview])
+    creator = instance_double(PostCreator)
+    allow(PostCreator).to receive(:new).and_return(creator)
+    allow(creator).to receive(:create!)
+        .and_raise(ActiveRecord::RecordNotUnique, 'other_unique_index')
+
+    expect {
+      described_class.new(actor:, rows: [row]).run
+    }.to raise_error(ActiveRecord::RecordNotUnique)
+  end
+
+  it 'converts a posts URL index race into a skip' do
+    existing = create(:post, url: 'https://example.com/index-race')
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([preview])
+    creator = instance_double(PostCreator)
+    allow(PostCreator).to receive(:new).and_return(creator)
+    allow(creator).to receive(:create!).and_raise(
+      ActiveRecord::RecordNotUnique,
+      'duplicate key index_posts_on_url'
+    )
+
+    result = described_class.new(
+      actor:,
+      rows: [row(url: 'https://EXAMPLE.com/index-race/')]
+    ).run.fetch(:rows).first
+
+    expect(result).to include(status: 'skipped', existing_post_id: existing.id)
+  end
+end
diff --git a/backend/spec/services/post_import_url_list_parser_spec.rb b/backend/spec/services/post_import_url_list_parser_spec.rb
new file mode 100644
index 0000000..0704abc
--- /dev/null
+++ b/backend/spec/services/post_import_url_list_parser_spec.rb
@@ -0,0 +1,40 @@
+require 'rails_helper'
+
+RSpec.describe PostImportUrlListParser do
+  describe '.parse' do
+    it 'trims URLs, ignores blank lines, and preserves source line numbers' do
+      source = "  https://example.com/one  \r\n\r\nhttps://example.com/two\n"
+
+      expect(described_class.parse(source)).to eq([
+        { source_row: 1, url: 'https://example.com/one' },
+        { source_row: 3, url: 'https://example.com/two' }
+      ])
+    end
+
+    it 'rejects an empty URL list' do
+      expect { described_class.parse(" \n\r\n") }
+          .to raise_error(ArgumentError, 'URL を入力してください．')
+    end
+
+    it 'rejects more than 100 non-empty rows' do
+      source = 101.times.map { |index| "https://example.com/#{ index }" }.join("\n")
+
+      expect { described_class.parse(source) }
+          .to raise_error(ArgumentError, '取込件数は 100 件までです．')
+    end
+
+    it 'includes the original line number in an oversized URL error' do
+      source = "\n#{ 'a' * (described_class::MAX_URL_BYTES + 1) }"
+
+      expect { described_class.parse(source) }
+          .to raise_error(ArgumentError, '2 行目: URL が長すぎます．')
+    end
+
+    it 'rejects an oversized request before parsing rows' do
+      source = 'a' * (described_class::MAX_BYTES + 1)
+
+      expect { described_class.parse(source) }
+          .to raise_error(ArgumentError, '入力が大きすぎます．')
+    end
+  end
+end
diff --git a/backend/spec/services/post_metadata_fetcher_spec.rb b/backend/spec/services/post_metadata_fetcher_spec.rb
new file mode 100644
index 0000000..38e5d53
--- /dev/null
+++ b/backend/spec/services/post_metadata_fetcher_spec.rb
@@ -0,0 +1,64 @@
+require 'rails_helper'
+
+RSpec.describe PostMetadataFetcher do
+  Response = Struct.new(:body)
+
+  def fetch_with_published_time(value, url: 'https://example.com/video')
+    html = <<~HTML
+      <html><head>
+        <meta property="article:published_time" content="#{ value }">
+      </head></html>
+    HTML
+    uri = URI.parse(url)
+    allow(Preview::UrlSafety).to receive(:validate).with(url).and_return([uri, ['8.8.8.8']])
+    allow(Preview::HttpFetcher).to receive(:fetch).and_return(Response.new(html))
+    allow(Preview::HtmlMetadataExtractor).to receive(:extract)
+        .and_return(title: 'title', image_url: nil)
+
+    described_class.fetch(url)
+  end
+
+  it 'builds ranges explicitly for year, month, and day precision' do
+    year = fetch_with_published_time('2024')
+    month = fetch_with_published_time('2024-02')
+    day = fetch_with_published_time('2024-02-03')
+
+    expect(year).to include(
+      original_created_from: Time.zone.local(2024, 1, 1).iso8601,
+      original_created_before: Time.zone.local(2025, 1, 1).iso8601
+    )
+    expect(month).to include(
+      original_created_from: Time.zone.local(2024, 2, 1).iso8601,
+      original_created_before: Time.zone.local(2024, 3, 1).iso8601
+    )
+    expect(day).to include(
+      original_created_from: Time.zone.local(2024, 2, 3).iso8601,
+      original_created_before: Time.zone.local(2024, 2, 4).iso8601
+    )
+  end
+
+  it 'preserves an input offset and fractional-second precision' do
+    result = fetch_with_published_time('2024-02-03T12:34:56.123+02:30')
+
+    expect(Time.iso8601(result.fetch(:original_created_from)))
+        .to eq(Time.iso8601('2024-02-03T12:34:56.123+02:30'))
+    expect(
+      Time.iso8601(result.fetch(:original_created_before)) -
+      Time.iso8601(result.fetch(:original_created_from))
+    ).to eq(0.001)
+    expect(result.fetch(:original_created_from)).to include('.123000000')
+  end
+
+  it 'adds platform tags for known video URLs' do
+    result = fetch_with_published_time('2024', url: 'https://youtu.be/abc123')
+
+    expect(result.fetch(:tags)).to eq('動画 YouTube')
+  end
+
+  it 'returns nil dates for an invalid timestamp' do
+    result = fetch_with_published_time('not-a-time')
+
+    expect(result.fetch(:original_created_from)).to be_nil
+    expect(result.fetch(:original_created_before)).to be_nil
+  end
+end
diff --git a/backend/spec/services/post_url_normaliser_spec.rb b/backend/spec/services/post_url_normaliser_spec.rb
new file mode 100644
index 0000000..dafcdb2
--- /dev/null
+++ b/backend/spec/services/post_url_normaliser_spec.rb
@@ -0,0 +1,27 @@
+require 'rails_helper'
+
+RSpec.describe PostUrlNormaliser do
+  before do
+    PostUrlSanitisationRule.unscoped.delete_all
+  end
+
+  describe '.normalise' do
+    it 'normalises the host and trailing slash before applying sanitisation rules' do
+      PostUrlSanitisationRule.create!(
+        priority: 10,
+        source_pattern: '\\Ahttps://example\\.com/source\\z',
+        replacement: 'https://example.com/canonical'
+      )
+
+      result = described_class.normalise('  https://EXAMPLE.com/source/  ')
+
+      expect(result).to eq('https://example.com/canonical')
+    end
+
+    it 'returns nil for unsupported or malformed URLs' do
+      expect(described_class.normalise('ftp://example.com/file')).to be_nil
+      expect(described_class.normalise('https://[')).to be_nil
+      expect(described_class.normalise('https:/path')).to be_nil
+    end
+  end
+end
diff --git a/frontend/src/components/TopNav.test.tsx b/frontend/src/components/TopNav.test.tsx
new file mode 100644
index 0000000..4d41dcd
--- /dev/null
+++ b/frontend/src/components/TopNav.test.tsx
@@ -0,0 +1,36 @@
+import { describe, expect, it } from 'vitest'
+
+import { menuOutline } from '@/components/TopNav'
+import { buildUser } from '@/test/factories'
+
+const submenuItem = (role: 'guest' | 'member' | 'admin', section: string, item: string) => {
+  const menu = menuOutline ({
+    user: buildUser ({ role }),
+    wikiId: section === 'Wiki' ? 10 : null,
+    pathName: section === 'Wiki' ? '/wiki/page' : '/posts' })
+  return menu.find (_1 => _1.name === section)?.subMenu.find (_1 => _1.name === item)
+}
+
+describe ('menuOutline', () => {
+  it ('uses content-edit permission for post, material, and Wiki actions', () => {
+    for (const role of ['member', 'admin'] as const)
+      {
+	expect (submenuItem (role, '広場', '追加')?.visible).toBe (true)
+	expect (submenuItem (role, '広場', '取込')?.visible).toBe (true)
+	expect (submenuItem (role, '素材', '追加')?.visible).toBe (true)
+	expect (submenuItem (role, 'Wiki', '新規')?.visible).toBe (true)
+	expect (submenuItem (role, 'Wiki', '編輯')?.visible).toBe (true)
+      }
+
+    expect (submenuItem ('guest', '広場', '追加')?.visible).toBe (false)
+    expect (submenuItem ('guest', '広場', '取込')?.visible).toBe (false)
+    expect (submenuItem ('guest', '素材', '追加')?.visible).toBe (false)
+    expect (submenuItem ('guest', 'Wiki', '新規')?.visible).toBe (false)
+    expect (submenuItem ('guest', 'Wiki', '編輯')?.visible).toBe (false)
+  })
+
+  it ('keeps material suppression admin-only', () => {
+    expect (submenuItem ('member', '素材', '抑止')?.visible).toBe (false)
+    expect (submenuItem ('admin', '素材', '抑止')?.visible).toBe (true)
+  })
+})
diff --git a/frontend/src/components/dialogues/DialogueProvider.test.tsx b/frontend/src/components/dialogues/DialogueProvider.test.tsx
new file mode 100644
index 0000000..d2bc4f8
--- /dev/null
+++ b/frontend/src/components/dialogues/DialogueProvider.test.tsx
@@ -0,0 +1,114 @@
+import { useCallback, useEffect } from 'react'
+import { fireEvent, render, screen, waitFor } from '@testing-library/react'
+import { describe, expect, it, vi } from 'vitest'
+
+import DialogueProvider from '@/components/dialogues/DialogueProvider'
+import useDialogue from '@/lib/dialogues/useDialogue'
+
+import type { DialogueFormControls } from '@/lib/dialogues/useDialogue'
+
+const FormBody = (
+    { controls,
+      onSelect }: { controls: DialogueFormControls
+		    onSelect: () => Promise<boolean> | boolean },
+) => {
+  useEffect (() => {
+    controls.setActions ([{
+      label: '左操作',
+      placement: 'start',
+      onSelect }, {
+      label: '保存',
+      onSelect: () => true }])
+  }, [controls, onSelect])
+
+  return <div>長いフォーム本文</div>
+}
+
+const NestedConfirmFormBody = ({ controls }: { controls: DialogueFormControls }) => {
+  const reset = useCallback (async () => {
+    await controls.confirm ({
+      title: '変更をリセットしますか?',
+      confirmText: 'リセット' })
+    return false
+  }, [controls])
+
+  return <FormBody controls={controls} onSelect={reset}/>
+}
+
+describe ('DialogueProvider', () => {
+  it ('keeps ordinary dialogues in FIFO order', async () => {
+    const Launcher = () => {
+      const dialogue = useDialogue ()
+      return (
+	  <button
+	      onClick={() => {
+		void dialogue.confirm ({ title: '一件目' })
+		void dialogue.confirm ({ title: '二件目' })
+	      }}>
+	    開く
+	  </button>)
+    }
+
+    render (<DialogueProvider><Launcher/></DialogueProvider>)
+    fireEvent.click (screen.getByRole ('button', { name: '開く' }))
+
+    expect (screen.getByText ('一件目')).toBeInTheDocument ()
+    expect (screen.queryByText ('二件目')).not.toBeInTheDocument ()
+    fireEvent.click (screen.getByRole ('button', { name: '確定' }))
+    expect (await screen.findByText ('二件目')).toBeInTheDocument ()
+  })
+
+  it ('keeps a large form open when an action returns false', async () => {
+    const action = vi.fn ().mockResolvedValue (false)
+    const Launcher = () => {
+      const dialogue = useDialogue ()
+      return (
+	  <button
+	      onClick={() => void dialogue.form ({
+		title: '投稿を編輯',
+		description: '説明',
+		size: 'large',
+		body: controls => <FormBody controls={controls} onSelect={action}/> })}>
+	    開く
+	  </button>)
+    }
+
+    render (<DialogueProvider><Launcher/></DialogueProvider>)
+    fireEvent.click (screen.getByRole ('button', { name: '開く' }))
+
+    const dialogue = screen.getByRole ('dialog')
+    expect (dialogue).toHaveClass ('max-h-[calc(100dvh-1rem)]', 'flex-col', 'max-w-3xl')
+    await waitFor (() => expect (screen.getByRole ('button', { name: '左操作' }))
+	.toBeInTheDocument ())
+    expect (screen.getByRole ('button', { name: '左操作' })).toHaveClass ('w-full', 'sm:w-auto')
+    fireEvent.click (screen.getByRole ('button', { name: '左操作' }))
+
+    await waitFor (() => expect (action).toHaveBeenCalledTimes (1))
+    expect (screen.getByText ('投稿を編輯')).toBeInTheDocument ()
+  })
+
+  it ('opens a nested confirmation over a form and returns to the same form', async () => {
+    const Launcher = () => {
+      const dialogue = useDialogue ()
+      return (
+	  <button
+	      onClick={() => void dialogue.form ({
+		title: '投稿を編輯',
+		body: controls => <NestedConfirmFormBody controls={controls}/> })}>
+	    開く
+	  </button>)
+    }
+
+    render (<DialogueProvider><Launcher/></DialogueProvider>)
+    fireEvent.click (screen.getByRole ('button', { name: '開く' }))
+    const action = await screen.findByRole ('button', { name: '左操作' })
+    fireEvent.click (action)
+
+    expect (await screen.findByText ('変更をリセットしますか?')).toBeInTheDocument ()
+    fireEvent.click (screen.getByRole ('button', { name: 'リセット' }))
+    await waitFor (() => {
+      expect (screen.queryByText ('変更をリセットしますか?')).not.toBeInTheDocument ()
+    })
+    expect (screen.getByText ('投稿を編輯')).toBeInTheDocument ()
+  })
+})
diff --git a/frontend/src/components/posts/import/PostImportRowForm.test.tsx b/frontend/src/components/posts/import/PostImportRowForm.test.tsx
new file mode 100644
index 0000000..26b3c79
--- /dev/null
+++ b/frontend/src/components/posts/import/PostImportRowForm.test.tsx
@@ -0,0 +1,91 @@
+import { act, render, screen, waitFor } from '@testing-library/react'
+import { describe, expect, it, vi } from 'vitest'
+
+import PostImportRowForm from '@/components/posts/import/PostImportRowForm'
+import { buildPostImportRow } from '@/test/postImportFactories'
+
+import type { DialogueFormAction, DialogueFormControls } from '@/lib/dialogues/useDialogue'
+
+describe ('PostImportRowForm', () => {
+  it ('resets only the draft, then saves with resetRequested', async () => {
+    const row = buildPostImportRow ()
+    row.attributes.title = 'manual title'
+    row.provenance.title = 'manual'
+    const actions: DialogueFormAction[][] = []
+    const controls: DialogueFormControls = {
+      close: vi.fn (),
+      confirm: vi.fn ().mockResolvedValue (true),
+      setActions: next => actions.push (next) }
+    const invalidRow = buildPostImportRow ({
+      validationErrors: { title: ['タイトルを確認してください．'] } })
+    const onSave = vi.fn ().mockResolvedValue ({ saved: false, row: invalidRow })
+
+    render (<PostImportRowForm row={row} controls={controls} onSave={onSave}/>)
+    const titleInput = screen.getByDisplayValue ('manual title')
+
+    await waitFor (() => expect (actions.at (-1)?.length).toBe (2))
+    const reset = actions.at (-1)?.find (_1 => _1.label === '変更をリセット')
+    expect (reset).toMatchObject ({ placement: 'start', variant: 'danger', disabled: false })
+    await act (async () => {
+      await reset?.onSelect ()
+    })
+
+    expect (controls.confirm).toHaveBeenCalled ()
+    expect (titleInput).toHaveValue ('')
+    expect (onSave).not.toHaveBeenCalled ()
+
+    const save = actions.at (-1)?.find (_1 => _1.label === '編輯内容を保存')
+    await act (async () => {
+      await save?.onSelect ()
+    })
+
+    expect (onSave).toHaveBeenCalledWith ({
+      draft: expect.objectContaining ({ title: '' }),
+      resetRequested: true })
+    expect (screen.getByText ('タイトルを確認してください．')).toBeInTheDocument ()
+  })
+
+  it ('does not reset the draft when confirmation is cancelled', async () => {
+    const row = buildPostImportRow ({ attributes: { title: 'manual title' } })
+    let actions: DialogueFormAction[] = []
+    const controls: DialogueFormControls = {
+      close: vi.fn (),
+      confirm: vi.fn ().mockResolvedValue (false),
+      setActions: next => {
+	actions = next
+      } }
+
+    render (
+	<PostImportRowForm
+	    row={row}
+	    controls={controls}
+	    onSave={vi.fn ()}/>)
+    await waitFor (() => expect (actions.length).toBe (2))
+
+    await act (async () => {
+      await actions.find (_1 => _1.label === '変更をリセット')?.onSelect ()
+    })
+
+    expect (screen.getByDisplayValue ('manual title')).toBeInTheDocument ()
+  })
+
+  it ('marks edited fields and areas invalid from field errors', () => {
+    const row = buildPostImportRow ({
+      validationErrors: { url: ['URL error'], tags: ['tag error'] },
+      importErrors: { duration: ['duration error'] },
+      fieldWarnings: { title: ['title warning'] } })
+
+    render (
+	<PostImportRowForm
+	    row={row}
+	    controls={{ close: vi.fn (), confirm: vi.fn (), setActions: vi.fn () }}
+	    onSave={vi.fn ()}/>)
+
+    expect (screen.getByText ('URL error')).toBeInTheDocument ()
+    expect (screen.getByText ('tag error')).toBeInTheDocument ()
+    expect (screen.getByText ('duration error')).toBeInTheDocument ()
+    expect (screen.getByText ('title warning')).toBeInTheDocument ()
+    expect (screen.getAllByRole ('textbox').filter (
+	_1 => _1.getAttribute ('aria-invalid') === 'true')).toHaveLength (3)
+  })
+})
diff --git a/frontend/src/components/posts/import/postImportRowStatus.test.ts b/frontend/src/components/posts/import/postImportRowStatus.test.ts
new file mode 100644
index 0000000..30e78fa
--- /dev/null
+++ b/frontend/src/components/posts/import/postImportRowStatus.test.ts
@@ -0,0 +1,27 @@
+import { describe, expect, it } from 'vitest'
+
+import { displayPostImportStatus } from '@/components/posts/import/postImportRowStatus'
+import { buildPostImportRow } from '@/test/postImportFactories'
+
+describe ('displayPostImportStatus', () => {
+  it ('shows only ready, warning, and skipped states', () => {
+    expect (displayPostImportStatus (buildPostImportRow ())).toBe ('ready')
+    expect (displayPostImportStatus (buildPostImportRow ({
+      status: 'warning',
+      fieldWarnings: { title: ['warning'] } }))).toBe ('warning')
+    expect (displayPostImportStatus (buildPostImportRow ({
+      skipReason: 'existing',
+      existingPostId: 2 }))).toBe ('skipped')
+  })
+
+  it ('does not expose validation, failure, or created states as badges', () => {
+    expect (displayPostImportStatus (buildPostImportRow ({
+      status: 'error',
+      validationErrors: { title: ['invalid'] } }))).toBeNull ()
+    expect (displayPostImportStatus (buildPostImportRow ({
+      importStatus: 'failed' }))).toBeNull ()
+    expect (displayPostImportStatus (buildPostImportRow ({
+      importStatus: 'created',
+      createdPostId: 3 }))).toBeNull ()
+  })
+})
diff --git a/frontend/src/lib/postImportRows.test.ts b/frontend/src/lib/postImportRows.test.ts
new file mode 100644
index 0000000..b1aeb01
--- /dev/null
+++ b/frontend/src/lib/postImportRows.test.ts
@@ -0,0 +1,147 @@
+import { describe, expect, it } from 'vitest'
+
+import { creatableImportRows,
+	 initialisePreviewRows,
+	 mergeImportResults,
+	 mergeValidatedImportRows,
+	 processableImportRows,
+	 resultSummaryCounts,
+	 retryImportRow,
+	 reviewSummaryCounts } from '@/lib/postImportSession'
+import { buildPostImportRow } from '@/test/postImportFactories'
+
+describe ('post import row state', () => {
+  it ('separates processable existing rows from creatable rows', () => {
+    const ready = buildPostImportRow ({ sourceRow: 1 })
+    const existing = buildPostImportRow ({
+      sourceRow: 2,
+      skipReason: 'existing',
+      existingPostId: 20 })
+    const invalid = buildPostImportRow ({
+      sourceRow: 3,
+      status: 'error',
+      validationErrors: { url: ['invalid'] } })
+    const created = buildPostImportRow ({
+      sourceRow: 4,
+      importStatus: 'created',
+      createdPostId: 40 })
+    const rows = [ready, existing, invalid, created]
+
+    expect (processableImportRows (rows)).toEqual ([ready, existing])
+    expect (creatableImportRows (rows)).toEqual ([ready])
+    expect (reviewSummaryCounts (rows)).toEqual ({
+      total: 4,
+      submittable: 1,
+      skipPlanned: 1 })
+  })
+
+  it ('preserves terminal rows while merging validation results', () => {
+    const created = buildPostImportRow ({
+      sourceRow: 1,
+      importStatus: 'created',
+      createdPostId: 10,
+      attributes: { title: 'created title' } })
+    const pending = buildPostImportRow ({
+      sourceRow: 2,
+      fieldWarnings: { title: ['old warning'] },
+      provenance: { title: 'manual' },
+      attributes: { title: 'manual title' } })
+    const validated = [
+      buildPostImportRow ({ sourceRow: 1, attributes: { title: 'changed' } }),
+      buildPostImportRow ({
+	sourceRow: 2,
+	fieldWarnings: { title: ['fetch warning'], tags: ['tag warning'] },
+	provenance: { title: 'manual' },
+	attributes: { title: 'manual title' } })]
+
+    const result = mergeValidatedImportRows ([created, pending], validated)
+
+    expect (result[0]).toBe (created)
+    expect (result[1]?.fieldWarnings).toEqual ({ tags: ['tag warning'] })
+  })
+
+  it ('updates the reset snapshot only after metadata URL changes', () => {
+    const current = buildPostImportRow ({
+      attributes: { title: 'manual title' },
+      metadataUrl: 'https://example.com/old' })
+    const validated = buildPostImportRow ({
+      attributes: { title: 'new metadata title' },
+      metadataUrl: 'https://example.com/new',
+      fieldWarnings: { title: ['warning'] },
+      baseWarnings: ['base warning'] })
+
+    const result = mergeValidatedImportRows ([current], [validated])[0]
+
+    expect (result?.resetSnapshot).toMatchObject ({
+      attributes: { title: 'new metadata title' },
+      fieldWarnings: { title: ['warning'] },
+      baseWarnings: ['base warning'],
+      metadataUrl: 'https://example.com/new' })
+  })
+
+  it ('merges result states and clears incompatible post identifiers', () => {
+    const created = mergeImportResults ([buildPostImportRow ({
+      skipReason: 'existing',
+      existingPostId: 2 })], [{
+      sourceRow: 1,
+      status: 'created',
+      post: { id: 3 } }])[0]
+    const skipped = mergeImportResults ([buildPostImportRow ({
+      createdPostId: 3,
+      importStatus: 'created' })], [{
+      sourceRow: 1,
+      status: 'skipped',
+      existingPostId: 4 }])[0]
+    const failed = mergeImportResults ([buildPostImportRow ({
+      skipReason: 'existing',
+      existingPostId: 4 })], [{
+      sourceRow: 1,
+      status: 'failed',
+      errors: { base: ['failure'] } }])[0]
+
+    expect (created).toMatchObject ({
+      importStatus: 'created',
+      createdPostId: 3,
+      existingPostId: undefined,
+      skipReason: undefined })
+    expect (skipped).toMatchObject ({
+      importStatus: 'skipped',
+      existingPostId: 4,
+      createdPostId: undefined,
+      skipReason: 'existing' })
+    expect (failed).toMatchObject ({
+      importStatus: 'failed',
+      createdPostId: undefined,
+      existingPostId: undefined,
+      skipReason: undefined,
+      importErrors: { base: ['failure'] } })
+  })
+
+  it ('retries only the selected failed row and counts results exclusively', () => {
+    const rows = [
+      buildPostImportRow ({ sourceRow: 1, importStatus: 'created', createdPostId: 1 }),
+      buildPostImportRow ({ sourceRow: 2, importStatus: 'skipped',
+	existingPostId: 2, skipReason: 'existing' }),
+      buildPostImportRow ({ sourceRow: 3, importStatus: 'failed',
+	importErrors: { base: ['failed'] } })]
+
+    expect (resultSummaryCounts (rows)).toEqual ({ created: 1, skipped: 1, failed: 1 })
+    expect (retryImportRow (rows, 3)[2]).toMatchObject ({
+      importStatus: 'pending',
+      importErrors: undefined })
+  })
+
+  it ('copies reset snapshot values instead of sharing mutable records', () => {
+    const row = buildPostImportRow ({ fieldWarnings: { title: ['warning'] } })
+    const initialised = initialisePreviewRows ([row])[0]
+    expect (initialised).toBeDefined ()
+    if (initialised == null)
+      return
+
+    initialised.attributes.title = 'changed'
+    initialised.fieldWarnings.title?.push ('another')
+
+    expect (initialised.resetSnapshot.attributes.title).toBe ('')
+    expect (initialised.resetSnapshot.fieldWarnings.title).toEqual (['warning'])
+  })
+})
diff --git a/frontend/src/lib/postImportSourceValidation.test.ts b/frontend/src/lib/postImportSourceValidation.test.ts
new file mode 100644
index 0000000..2f565f5
--- /dev/null
+++ b/frontend/src/lib/postImportSourceValidation.test.ts
@@ -0,0 +1,49 @@
+import { describe, expect, it } from 'vitest'
+
+import { countImportSourceLines, validateImportSource } from '@/lib/postImportSession'
+
+describe ('post import source validation', () => {
+  it ('counts trimmed non-empty CRLF and LF rows', () => {
+    expect (countImportSourceLines (' one \r\n\r\n two\n')).toBe (2)
+  })
+
+  it ('reports invalid protocols and malformed URLs with original line numbers', () => {
+    const issues = validateImportSource (
+        '\nftp://example.com/file\nhttps://exa mple.com/path')
+
+    expect (issues).toEqual ([
+      {
+	sourceRow: 2,
+	message: 'HTTP または HTTPS の URL ではありません．',
+	url: 'ftp://example.com/file' },
+      {
+	sourceRow: 3,
+	message: 'URL の形式が不正です．',
+	url: 'https://exa mple.com/path' }])
+  })
+
+  it ('detects duplicates after frontend URL normalisation', () => {
+    const issues = validateImportSource (
+        'https://EXAMPLE.com/path/\nhttps://example.com/path')
+
+    expect (issues).toEqual ([{
+      sourceRow: 2,
+      message: '1 行目と同じ URL です．',
+      url: 'https://example.com/path' }])
+  })
+
+  it ('rejects oversized URLs and rows beyond the maximum count', () => {
+    const oversized = `https://example.com/${ 'a'.repeat (20 * 1024) }`
+    const tooMany = Array.from (
+        { length: 101 },
+        (_, index) => `https://example.com/${ index }`).join ('\n')
+
+    expect (validateImportSource (oversized)[0]).toMatchObject ({
+      sourceRow: 1,
+      message: 'URL が長すぎます．' })
+    expect (validateImportSource (tooMany).at (-1)).toEqual ({
+      sourceRow: 101,
+      message: '取込件数は 100 件までです．',
+      url: 'https://example.com/100' })
+  })
+})
diff --git a/frontend/src/lib/postImportStorage.test.ts b/frontend/src/lib/postImportStorage.test.ts
new file mode 100644
index 0000000..9bed899
--- /dev/null
+++ b/frontend/src/lib/postImportStorage.test.ts
@@ -0,0 +1,114 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { cleanupExpiredPostImportSessions,
+	 clearPostImportSourceDraft,
+	 loadPostImportSession,
+	 loadPostImportSourceDraft,
+	 savePostImportSession,
+	 savePostImportSourceDraft } from '@/lib/postImportSession'
+import { buildPostImportRow } from '@/test/postImportFactories'
+
+describe ('post import storage', () => {
+  beforeEach (() => {
+    sessionStorage.clear ()
+    vi.useRealTimers ()
+  })
+
+  it ('round-trips a valid session and source draft', () => {
+    const row = buildPostImportRow ({
+      importStatus: 'skipped',
+      skipReason: 'existing',
+      existingPostId: 10 })
+
+    expect (savePostImportSession ('session', {
+      source: row.url,
+      rows: [row],
+      repairMode: 'all' })).toBe (true)
+    expect (loadPostImportSession ('session')).toMatchObject ({
+      version: 2,
+      source: row.url,
+      rows: [{
+	importStatus: 'skipped',
+	skipReason: 'existing',
+	existingPostId: 10 }] })
+
+    expect (savePostImportSourceDraft ('https://example.com')).toBe (true)
+    expect (loadPostImportSourceDraft ()).toEqual ({ source: 'https://example.com' })
+    clearPostImportSourceDraft ()
+    expect (loadPostImportSourceDraft ()).toEqual ({ source: '' })
+  })
+
+  it ('rejects inconsistent post IDs and terminal statuses', () => {
+    const session = {
+      version: 2,
+      savedAt: new Date ().toISOString (),
+      source: '',
+      repairMode: 'all',
+      rows: [buildPostImportRow ()] }
+    const invalidRows = [
+      { ...session.rows[0], skipReason: 'existing', existingPostId: undefined },
+      { ...session.rows[0], existingPostId: 2, skipReason: undefined },
+      { ...session.rows[0], importStatus: 'created', createdPostId: undefined },
+      { ...session.rows[0], importStatus: 'failed', createdPostId: 3 }]
+
+    for (const [index, row] of invalidRows.entries ())
+      {
+	sessionStorage.setItem (`post-import-session:invalid-${ index }`, JSON.stringify ({
+	  ...session,
+	  rows: [row] }))
+	expect (loadPostImportSession (`invalid-${ index }`)).toBeNull ()
+      }
+  })
+
+  it ('rejects invalid attribute, provenance, tag-source, and snapshot data', () => {
+    const row = buildPostImportRow ()
+    const invalidRows = [
+      { ...row, attributes: { title: [] } },
+      { ...row, attributes: { unknown: 'value' } },
+      { ...row, provenance: { title: 'mapped' } },
+      { ...row, tagSources: { mapped: 'tag' } },
+      { ...row, resetSnapshot: { ...row.resetSnapshot,
+	fieldWarnings: { title: 'warning' } } }]
+
+    invalidRows.forEach ((invalidRow, index) => {
+      sessionStorage.setItem (`post-import-session:shape-${ index }`, JSON.stringify ({
+	version: 2,
+	savedAt: new Date ().toISOString (),
+	source: '',
+	rows: [invalidRow],
+	repairMode: 'all' }))
+      expect (loadPostImportSession (`shape-${ index }`)).toBeNull ()
+    })
+  })
+
+  it ('removes expired and malformed sessions without touching current sessions', () => {
+    const current = {
+      version: 2,
+      savedAt: new Date ().toISOString (),
+      source: '',
+      rows: [buildPostImportRow ()],
+      repairMode: 'all' }
+    const expired = {
+      ...current,
+      savedAt: new Date (Date.now () - 25 * 60 * 60 * 1000).toISOString () }
+    sessionStorage.setItem ('post-import-session:current', JSON.stringify (current))
+    sessionStorage.setItem ('post-import-session:expired', JSON.stringify (expired))
+    sessionStorage.setItem ('post-import-session:malformed', '{')
+
+    cleanupExpiredPostImportSessions ()
+
+    expect (sessionStorage.getItem ('post-import-session:current')).not.toBeNull ()
+    expect (sessionStorage.getItem ('post-import-session:expired')).toBeNull ()
+    expect (sessionStorage.getItem ('post-import-session:malformed')).toBeNull ()
+  })
+
+  it ('reports storage access failures without throwing', () => {
+    const onError = vi.fn ()
+    vi.spyOn (Storage.prototype, 'setItem').mockImplementation (() => {
+      throw new DOMException ('quota')
+    })
+
+    expect (savePostImportSourceDraft ('source', onError)).toBe (false)
+    expect (onError).toHaveBeenCalledWith ('ブラウザへ保存できませんでした．')
+  })
+})
diff --git a/frontend/src/pages/posts/PostImportResultPage.test.tsx b/frontend/src/pages/posts/PostImportResultPage.test.tsx
new file mode 100644
index 0000000..4a07415
--- /dev/null
+++ b/frontend/src/pages/posts/PostImportResultPage.test.tsx
@@ -0,0 +1,82 @@
+import { fireEvent, screen } from '@testing-library/react'
+import { Route, Routes, useLocation } from 'react-router-dom'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { savePostImportSession } from '@/lib/postImportSession'
+import PostImportResultPage from '@/pages/posts/PostImportResultPage'
+import { buildUser } from '@/test/factories'
+import { buildPostImportRow } from '@/test/postImportFactories'
+import { renderWithProviders } from '@/test/render'
+
+const api = vi.hoisted (() => ({ apiPost: vi.fn () }))
+const toastApi = vi.hoisted (() => ({ toast: vi.fn () }))
+
+vi.mock ('@/lib/api', () => api)
+vi.mock ('@/components/ui/use-toast', () => toastApi)
+
+const ReviewLocation = () => {
+  const location = useLocation ()
+  return <div>{`review route ${ location.search }`}</div>
+}
+
+const renderPage = () => renderWithProviders (
+    <Routes>
+      <Route
+	  path="/posts/import/:sessionId/result"
+	  element={<PostImportResultPage user={buildUser ()}/>}/>
+      <Route path="/posts/import/:sessionId/review" element={<ReviewLocation/>}/>
+    </Routes>,
+    { route: '/posts/import/session/result' })
+
+describe ('PostImportResultPage', () => {
+  beforeEach (() => {
+    sessionStorage.clear ()
+    vi.clearAllMocks ()
+  })
+
+  it ('shows exclusive result counts, post links, and failed-row actions', async () => {
+    const rows = [
+      buildPostImportRow ({ sourceRow: 1, importStatus: 'created', createdPostId: 11 }),
+      buildPostImportRow ({ sourceRow: 2, importStatus: 'skipped',
+	skipReason: 'existing', existingPostId: 22 }),
+      buildPostImportRow ({ sourceRow: 3, importStatus: 'failed',
+	importErrors: { base: ['登録中に失敗しました．'] } })]
+    savePostImportSession ('session', { source: '', rows, repairMode: 'all' })
+
+    renderPage ()
+
+    expect (await screen.findByText (
+	/登録成功\s*1件.*スキップ\s*1件.*失敗\s*1件/)).toBeInTheDocument ()
+    expect (screen.getAllByRole ('link', { name: '投稿を開く' })
+	.map (_1 => _1.getAttribute ('href'))).toEqual (['/posts/11', '/posts/22'])
+    expect (screen.getByText ('登録中に失敗しました．')).toBeInTheDocument ()
+    expect (screen.getByRole ('button', { name: '編輯' })).toBeInTheDocument ()
+    expect (screen.getByRole ('button', { name: '再試行' })).toBeInTheDocument ()
+  })
+
+  it ('returns a retry validation error to the review dialogue route', async () => {
+    const failed = buildPostImportRow ({
+      importStatus: 'failed',
+      importErrors: { base: ['old error'] } })
+    const invalid = buildPostImportRow ({
+      importStatus: 'pending',
+      status: 'error',
+      validationErrors: { title: ['タイトルを確認してください．'] } })
+    savePostImportSession ('session', {
+      source: failed.url,
+      rows: [failed],
+      repairMode: 'all' })
+    api.apiPost.mockResolvedValue ({ rows: [invalid] })
+
+    renderPage ()
+    fireEvent.click (await screen.findByRole ('button', { name: '再試行' }))
+
+    expect (await screen.findByText ('review route ?edit=1')).toBeInTheDocument ()
+    expect (api.apiPost).toHaveBeenCalledTimes (1)
+    const saved = JSON.parse (
+	sessionStorage.getItem ('post-import-session:session') ?? '{}')
+    expect (saved.rows[0]).toMatchObject ({
+      importStatus: 'pending',
+      validationErrors: { title: ['タイトルを確認してください．'] } })
+  })
+})
diff --git a/frontend/src/pages/posts/PostImportReviewPage.test.tsx b/frontend/src/pages/posts/PostImportReviewPage.test.tsx
new file mode 100644
index 0000000..3e6d409
--- /dev/null
+++ b/frontend/src/pages/posts/PostImportReviewPage.test.tsx
@@ -0,0 +1,78 @@
+import { fireEvent, screen, waitFor } from '@testing-library/react'
+import { Route, Routes } from 'react-router-dom'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { savePostImportSession } from '@/lib/postImportSession'
+import PostImportReviewPage from '@/pages/posts/PostImportReviewPage'
+import { buildUser } from '@/test/factories'
+import { buildPostImportRow } from '@/test/postImportFactories'
+import { renderWithProviders } from '@/test/render'
+
+const api = vi.hoisted (() => ({ apiPost: vi.fn () }))
+const toastApi = vi.hoisted (() => ({ toast: vi.fn () }))
+
+vi.mock ('@/lib/api', () => api)
+vi.mock ('@/components/ui/use-toast', () => toastApi)
+
+const renderPage = () => renderWithProviders (
+    <Routes>
+      <Route
+	  path="/posts/import/:sessionId/review"
+	  element={<PostImportReviewPage user={buildUser ()}/>}/>
+      <Route path="/posts/import/:sessionId/result" element={<div>result route</div>}/>
+    </Routes>,
+    { route: '/posts/import/session/review' })
+
+describe ('PostImportReviewPage', () => {
+  beforeEach (() => {
+    sessionStorage.clear ()
+    vi.clearAllMocks ()
+  })
+
+  it ('keeps the review route and opens the first invalid row dialogue', async () => {
+    const row = buildPostImportRow ({ attributes: { title: 'title' } })
+    savePostImportSession ('session', { source: row.url, rows: [row], repairMode: 'all' })
+    api.apiPost.mockResolvedValue ({ rows: [buildPostImportRow ({
+      attributes: { title: 'title' },
+      status: 'error',
+      validationErrors: { title: ['タイトルを確認してください．'] } })] })
+
+    renderPage ()
+    fireEvent.click (await screen.findByRole ('button', { name: '取込実行' }))
+
+    expect (await screen.findByText ('投稿を編輯')).toBeInTheDocument ()
+    expect (screen.getByText ('タイトルを確認してください．')).toBeInTheDocument ()
+    expect (api.apiPost).toHaveBeenCalledTimes (1)
+    expect (screen.queryByText ('result route')).not.toBeInTheDocument ()
+  })
+
+  it ('submits existing rows for a formal skipped result and opens result route', async () => {
+    const row = buildPostImportRow ({
+      skipReason: 'existing',
+      existingPostId: 10 })
+    savePostImportSession ('session', { source: row.url, rows: [row], repairMode: 'all' })
+    api.apiPost
+	.mockResolvedValueOnce ({ rows: [row] })
+	.mockResolvedValueOnce ({
+	  created: 0,
+	  skipped: 1,
+	  failed: 0,
+	  rows: [{ sourceRow: 1, status: 'skipped', existingPostId: 10 }] })
+
+    renderPage ()
+    fireEvent.click (await screen.findByRole ('button', { name: '取込実行' }))
+
+    expect (await screen.findByText ('result route')).toBeInTheDocument ()
+    expect (api.apiPost).toHaveBeenCalledTimes (2)
+    expect (api.apiPost.mock.calls[1]?.[1]).toMatchObject ({
+      rows: [expect.objectContaining ({ sourceRow: 1, url: row.url })] })
+    await waitFor (() => {
+      const saved = JSON.parse (
+	  sessionStorage.getItem ('post-import-session:session') ?? '{}')
+      expect (saved.rows[0]).toMatchObject ({
+	importStatus: 'skipped',
+	existingPostId: 10,
+	skipReason: 'existing' })
+    })
+  })
+})
diff --git a/frontend/src/pages/posts/PostImportSourcePage.test.tsx b/frontend/src/pages/posts/PostImportSourcePage.test.tsx
new file mode 100644
index 0000000..a8d5af5
--- /dev/null
+++ b/frontend/src/pages/posts/PostImportSourcePage.test.tsx
@@ -0,0 +1,92 @@
+import { fireEvent, screen, waitFor } from '@testing-library/react'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import PostImportSourcePage from '@/pages/posts/PostImportSourcePage'
+import { buildUser } from '@/test/factories'
+import { buildPostImportRow } from '@/test/postImportFactories'
+import { renderWithProviders } from '@/test/render'
+
+const api = vi.hoisted (() => ({
+  apiPost: vi.fn (),
+  isApiError: vi.fn () }))
+
+const router = vi.hoisted (() => ({ navigate: vi.fn () }))
+
+const toastApi = vi.hoisted (() => ({ toast: vi.fn () }))
+
+vi.mock ('@/lib/api', () => api)
+vi.mock ('@/components/ui/use-toast', () => toastApi)
+vi.mock ('react-router-dom', async importOriginal => ({
+  ...await importOriginal<typeof import('react-router-dom')> (),
+  useNavigate: () => router.navigate }))
+
+describe ('PostImportSourcePage', () => {
+  beforeEach (() => {
+    sessionStorage.clear ()
+    vi.clearAllMocks ()
+    api.isApiError.mockReturnValue (false)
+  })
+
+  it ('shows no empty error initially and validates only after Next is pressed', () => {
+    renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
+
+    expect (screen.queryByText ('URL を入力してください．')).not.toBeInTheDocument ()
+    fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
+    expect (screen.getByText ('URL を入力してください．')).toBeInTheDocument ()
+    expect (api.apiPost).not.toHaveBeenCalled ()
+  })
+
+  it ('shows frontend URL issues with line numbers without requesting preview', () => {
+    renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
+    const input = screen.getByRole ('textbox', { name: '' })
+
+    fireEvent.change (input, {
+      target: { value: '\nftp://example.com/file\nhttps://example.com/valid' } })
+    expect (screen.queryByText (/2 行目/)).not.toBeInTheDocument ()
+    fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
+
+    expect (screen.getByText (/2 行目: HTTP または HTTPS/)).toBeInTheDocument ()
+    expect (screen.getByText ('ftp://example.com/file')).toBeInTheDocument ()
+    expect (input).toHaveAttribute ('aria-invalid', 'true')
+    expect (input.getAttribute ('aria-describedby')).toContain ('post-import-source-issues')
+    expect (api.apiPost).not.toHaveBeenCalled ()
+  })
+
+  it ('shows backend URL errors against original input without a session', async () => {
+    api.apiPost.mockResolvedValue ({
+      rows: [buildPostImportRow ({
+	sourceRow: 2,
+	url: 'https://example.com/canonical',
+	status: 'error',
+	validationErrors: { url: ['URL が重複しています．'] } })] })
+    renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
+
+    fireEvent.change (screen.getByRole ('textbox', { name: '' }), {
+      target: { value: '\nhttps://example.com/original' } })
+    fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
+
+    expect (await screen.findByText ('2 行目: URL が重複しています．')).toBeInTheDocument ()
+    expect (screen.getAllByText ('https://example.com/original')).toHaveLength (2)
+    expect (router.navigate).not.toHaveBeenCalled ()
+    expect (Array.from ({ length: sessionStorage.length }, (_, index) =>
+	sessionStorage.key (index))).not.toContainEqual(
+	    expect.stringMatching (/^post-import-session:/))
+  })
+
+  it ('stores a successful preview before navigating to the review route', async () => {
+    api.apiPost.mockResolvedValue ({ rows: [buildPostImportRow ()] })
+    renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
+
+    fireEvent.change (screen.getByRole ('textbox', { name: '' }), {
+      target: { value: 'https://example.com/post' } })
+    fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
+
+    await waitFor (() => {
+      expect (router.navigate).toHaveBeenCalledWith (
+	  expect.stringMatching (/^\/posts\/import\/[^/]+\/review$/))
+    })
+    const sessionKeys = Array.from ({ length: sessionStorage.length }, (_, index) =>
+	sessionStorage.key (index)).filter (_1 => _1?.startsWith ('post-import-session:'))
+    expect (sessionKeys).toHaveLength (1)
+  })
+})
diff --git a/frontend/src/test/postImportFactories.ts b/frontend/src/test/postImportFactories.ts
new file mode 100644
index 0000000..cc6a10a
--- /dev/null
+++ b/frontend/src/test/postImportFactories.ts
@@ -0,0 +1,52 @@
+import type { PostImportRow } from '@/lib/postImportSession'
+
+export const buildPostImportRow = (
+    overrides: Partial<PostImportRow> = {},
+): PostImportRow => {
+  const attributes = {
+    title: '',
+    thumbnailBase: '',
+    originalCreatedFrom: '',
+    originalCreatedBefore: '',
+    duration: '',
+    tags: '',
+    parentPostIds: '',
+    ...overrides.attributes }
+  const provenance = {
+    url: 'manual' as const,
+    title: 'automatic' as const,
+    thumbnailBase: 'automatic' as const,
+    originalCreatedFrom: 'automatic' as const,
+    originalCreatedBefore: 'automatic' as const,
+    duration: 'automatic' as const,
+    tags: 'automatic' as const,
+    parentPostIds: 'automatic' as const,
+    ...overrides.provenance }
+  const fieldWarnings = { ...overrides.fieldWarnings }
+  const baseWarnings = [...(overrides.baseWarnings ?? [])]
+  const tagSources = {
+    automatic: overrides.tagSources?.automatic ?? '',
+    manual: overrides.tagSources?.manual ?? '' }
+  const url = overrides.url ?? 'https://example.com/post'
+
+  return {
+    ...overrides,
+    sourceRow: overrides.sourceRow ?? 1,
+    url,
+    attributes,
+    fieldWarnings,
+    baseWarnings,
+    validationErrors: overrides.validationErrors ?? {},
+    provenance,
+    tagSources,
+    status: overrides.status ?? 'ready',
+    resetSnapshot: overrides.resetSnapshot ?? {
+	url,
+	attributes: { ...attributes },
+	provenance: { ...provenance },
+	tagSources: { ...tagSources },
+	fieldWarnings: Object.fromEntries (
+	    Object.entries (fieldWarnings).map (([key, values]) => [key, [...values]])),
+	baseWarnings: [...baseWarnings],
+	metadataUrl: overrides.metadataUrl } }
+}