diff --git a/backend/routes/pdf.js b/backend/routes/pdf.js
new file mode 100644
index 0000000..7ddcdde
--- /dev/null
+++ b/backend/routes/pdf.js
@@ -0,0 +1,153 @@
+const { Router } = require('express');
+const { v4: uuidv4 } = require('uuid');
+const { authMiddleware } = require('../auth');
+const { getBoard, getCollectionMember, getImage, getPdfPage, getPdfPages, createMediaJob } = require('../db');
+
+const router = Router();
+
+// All routes require auth
+router.use(authMiddleware);
+
+/**
+ * Helper: check board access for editor+
+ */
+function checkEditorAccess(req, res) {
+  const board = getBoard(req.params.boardId);
+  if (!board) {
+    res.status(404).json({ error: 'Board not found' });
+    return null;
+  }
+
+  const member = getCollectionMember(board.collection_id, req.user.id);
+  const hierarchy = { owner: 3, editor: 2, viewer: 1 };
+  if (!member || (hierarchy[member.role] || 0) < 2) {
+    res.status(403).json({ error: 'Editor or owner access required' });
+    return null;
+  }
+
+  return board;
+}
+
+/**
+ * POST /api/boards/:boardId/pdf-pages
+ * Request hi-res rendering for selected PDF pages.
+ * Body: { imageId, pages: [1, 2, 3, ...] }
+ * Max 50 pages per request.
+ */
+router.post('/:boardId/pdf-pages', async (req, res) => {
+  try {
+    const board = checkEditorAccess(req, res);
+    if (!board) return;
+
+    const { imageId, pages } = req.body;
+    if (!imageId || !Array.isArray(pages) || pages.length === 0) {
+      return res.status(400).json({ error: 'imageId and pages[] are required' });
+    }
+
+    if (pages.length > 50) {
+      return res.status(400).json({ error: 'Maximum 50 pages per request' });
+    }
+
+    const image = getImage(imageId);
+    if (!image || image.board_id !== board.id) {
+      return res.status(404).json({ error: 'Image not found on this board' });
+    }
+
+    const results = [];
+    for (const pageNum of pages) {
+      const page = getPdfPage(imageId, pageNum);
+      if (!page) continue;
+
+      // Skip if hires already done
+      if (page.hires_asset_key) {
+        results.push(page);
+        continue;
+      }
+
+      // Check for existing pending/processing hires job for this page
+      const { db } = require('../db');
+      const existingJob = db.prepare(
+        `SELECT id FROM media_jobs WHERE image_id = ? AND type = 'pdf-hires' AND result_json LIKE ? AND status IN ('queued', 'processing')`
+      ).get(imageId, `%"pageNumber":${pageNum}%`);
+
+      if (!existingJob) {
+        createMediaJob({
+          id: uuidv4(),
+          imageId,
+          boardId: board.id,
+          type: 'pdf-hires',
+          priority: 10,
+          metaJson: JSON.stringify({ pageNumber: pageNum }),
+        });
+      }
+
+      results.push(page);
+    }
+
+    return res.json({ pages: results });
+  } catch (err) {
+    console.error('[pdf] pdf-pages error:', err);
+    return res.status(500).json({ error: 'Internal server error' });
+  }
+});
+
+/**
+ * POST /api/boards/:boardId/pdf-thumbnails
+ * Lazy-load thumbnails for PDF pages not yet rendered.
+ * Body: { imageId, pages: [1, 2, 3, ...] }
+ * Idempotent — skips pages with existing thumbs or pending jobs.
+ */
+router.post('/:boardId/pdf-thumbnails', async (req, res) => {
+  try {
+    const board = checkEditorAccess(req, res);
+    if (!board) return;
+
+    const { imageId, pages } = req.body;
+    if (!imageId || !Array.isArray(pages) || pages.length === 0) {
+      return res.status(400).json({ error: 'imageId and pages[] are required' });
+    }
+
+    const image = getImage(imageId);
+    if (!image || image.board_id !== board.id) {
+      return res.status(404).json({ error: 'Image not found on this board' });
+    }
+
+    const results = [];
+    for (const pageNum of pages) {
+      const page = getPdfPage(imageId, pageNum);
+      if (!page) continue;
+
+      // Skip if thumb already exists
+      if (page.thumb_asset_key) {
+        results.push(page);
+        continue;
+      }
+
+      // Skip if job already pending
+      const { db } = require('../db');
+      const existingJob = db.prepare(
+        `SELECT id FROM media_jobs WHERE image_id = ? AND type = 'pdf-thumbnail' AND result_json LIKE ? AND status IN ('queued', 'processing')`
+      ).get(imageId, `%"pageNumber":${pageNum}%`);
+
+      if (!existingJob) {
+        createMediaJob({
+          id: uuidv4(),
+          imageId,
+          boardId: board.id,
+          type: 'pdf-thumbnail',
+          priority: 0,
+          metaJson: JSON.stringify({ pageNumber: pageNum }),
+        });
+      }
+
+      results.push(page);
+    }
+
+    return res.json({ pages: results });
+  } catch (err) {
+    console.error('[pdf] pdf-thumbnails error:', err);
+    return res.status(500).json({ error: 'Internal server error' });
+  }
+});
+
+module.exports = router;
diff --git a/backend/server.js b/backend/server.js
index 379010d..7c161c4 100644
--- a/backend/server.js
+++ b/backend/server.js
@@ -102,6 +102,7 @@ const uploadRoutes = require('./routes/upload');
 const adminRoutes = require('./routes/admin');
 const mmBridgeRoutes = require('./routes/mattermost-bridge');
 const threadRoutes = require('./routes/threads');
+const pdfRoutes = require('./routes/pdf');
 
 app.use('/api/auth', authRoutes);
 app.use('/api/auth', oauthRoutes);
@@ -111,6 +112,7 @@ app.use('/api/upload', uploadRoutes);
 app.use('/api/admin', adminRoutes);
 app.use('/api/boards', mmBridgeRoutes);
 app.use('/api/boards', threadRoutes);
+app.use('/api/boards', pdfRoutes);
 
 // Public shared collection route (no auth required)
 app.get('/api/c/:shareToken', (req, res) => {