diff --git a/scraper/internal/server/ui.go b/scraper/internal/server/ui.go
index daa318c..f4e471c 100644
--- a/scraper/internal/server/ui.go
+++ b/scraper/internal/server/ui.go
@@ -1769,7 +1769,7 @@ const bookTmpl = `
     </div>
   </div>
 
-  <!-- Resume reading button — populated by JS from localStorage -->
+  <!-- Resume reading button — populated by JS from /api/progress -->
   <div id="resume-bar" class="mb-4 hidden">
     <a id="resume-link"
        hx-target="#main-content"
@@ -1874,16 +1874,8 @@ const bookTmpl = `
 
 (function () {
   var SLUG = '{{.Slug}}';
-  var LS_KEY = 'reading_progress';
-
-  function getProgress() {
-    try { return JSON.parse(localStorage.getItem(LS_KEY) || '{}'); } catch(_) { return {}; }
-  }
-
-  window.applyProgress = function(slug) {
-    var progress = getProgress();
-    var saved = progress[slug];
 
+  function applyProgressData(slug, saved) {
     // Show/hide latest bar (only when no progress recorded for this book).
     var latestBar = document.getElementById('latest-bar');
     if (latestBar) {
@@ -1918,6 +1910,13 @@ const bookTmpl = `
       htmx.process(link);
       bar.classList.remove('hidden');
     }
+  }
+
+  window.applyProgress = function(slug) {
+    fetch('/api/progress')
+      .then(function(r) { return r.ok ? r.json() : {}; })
+      .then(function(data) { applyProgressData(slug, data[slug] || null); })
+      .catch(function() { applyProgressData(slug, null); });
   };
 
   applyProgress(SLUG);
@@ -2471,14 +2470,11 @@ const chapterTmpl = `
 
   // ── reading progress ──────────────────────────────────────────────────────
   (function saveProgress() {
-    try {
-      var p = JSON.parse(localStorage.getItem('reading_progress') || '{}');
-      p[SLUG] = CHAPTER_N;
-      localStorage.setItem('reading_progress', JSON.stringify(p));
-      var ts = JSON.parse(localStorage.getItem('reading_progress_ts') || '{}');
-      ts[SLUG] = Date.now();
-      localStorage.setItem('reading_progress_ts', JSON.stringify(ts));
-    } catch(_) {}
+    fetch('/api/progress/' + encodeURIComponent(SLUG), {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ chapter: CHAPTER_N })
+    }).catch(function() {});
   })();
 
   // ── generation counter (stale-closure guard) ──────────────────────────────