diff --git a/client/pages/SubscriptionsPage.jsx b/client/pages/SubscriptionsPage.jsx
index d38cf6a..f8322a0 100644
--- a/client/pages/SubscriptionsPage.jsx
+++ b/client/pages/SubscriptionsPage.jsx
@@ -48,6 +48,8 @@ import BillModal from '@/components/BillModal';
 import BillHistoricalImportDialog from '@/components/BillHistoricalImportDialog';
 import { getLinkImportPref } from '@/pages/SettingsPage';
 import { useSearchPanelPreference } from '@/hooks/useSearchPanelPreference';
+import { useOptimistic } from '@/hooks/useOptimistic';
+import { useVirtualizer } from '@tanstack/react-virtual';
 import { moveInArray, movedItemId, reorderPayload } from '@/lib/reorder';
 
 const TYPE_LABELS = {
@@ -1100,15 +1102,14 @@ export default function SubscriptionsPage() {
   }
 
   async function toggleSubscription(item) {
-    setBusyId(`toggle-${item.id}`);
+    const newActive = !item.active;
+    addOptimisticSub({ id: item.id, active: newActive }); // instant — no spinner
     try {
-      await api.updateSubscription(item.id, { active: !item.active });
-      toast.success(item.active ? 'Subscription paused' : 'Subscription resumed');
-      await load();
+      await api.updateSubscription(item.id, { active: newActive });
+      await load(); // reconciles optimistic state
     } catch (err) {
       toast.error(err.message || 'Subscription could not be updated.');
-    } finally {
-      setBusyId(null);
+      await load(); // revert via useOptimistic reconciliation
     }
   }
 
@@ -1245,15 +1246,23 @@ export default function SubscriptionsPage() {
 
   const summary = data.summary || {};
   const subscriptions = data.subscriptions || [];
+
+  const [optimisticSubs, addOptimisticSub] = useOptimistic(
+    subscriptions,
+    useCallback((state, { id, active }) => state.map(s => s.id === id ? { ...s, active } : s), []),
+  );
+
   const filteredSubscriptions = useMemo(() => {
     const q = subSearch.trim().toLowerCase();
-    if (!q) return subscriptions;
-    return subscriptions.filter(item =>
-      String(item.name || '').toLowerCase().includes(q) ||
-      String(item.subscription_type || '').toLowerCase().includes(q) ||
-      String(item.category_name || '').toLowerCase().includes(q)
-    );
-  }, [subscriptions, subSearch]);
+    const base = q
+      ? optimisticSubs.filter(item =>
+          String(item.name || '').toLowerCase().includes(q) ||
+          String(item.subscription_type || '').toLowerCase().includes(q) ||
+          String(item.category_name || '').toLowerCase().includes(q)
+        )
+      : optimisticSubs;
+    return base;
+  }, [optimisticSubs, subSearch]);
   const active = filteredSubscriptions.filter(item => item.active);
   const paused = filteredSubscriptions.filter(item => !item.active);
   const sortedActive = useMemo(
@@ -1266,18 +1275,59 @@ export default function SubscriptionsPage() {
   );
   const reorderEnabled = !loading && bills.length > 0 && subscriptionSort === 'custom';
 
+  // Flat item list for virtualizer — cadence mode only (custom mode needs DOM order for drag-reorder)
+  const flatVirtualItems = useMemo(() => {
+    if (subscriptionSort !== 'cadence') return null;
+    const items = [];
+    const buildGroup = (group, activeState) => {
+      GROUP_ORDER.forEach(groupKey => {
+        const groupItems = group.filter(item => subscriptionGroup(item) === groupKey);
+        if (!groupItems.length) return;
+        const sectionKey = `${activeState ? 'active' : 'paused'}-${groupKey}`;
+        const monthlySum = groupItems.reduce((s, i) => s + (Number(i.monthly_equivalent) || 0), 0);
+        items.push({ type: 'group-header', sectionKey, groupKey, activeState, groupItems, monthlySum });
+        if (!collapsedGroups.has(sectionKey)) {
+          groupItems.forEach((item, i) => items.push({ type: 'row', item, groupItems, activeState, i }));
+        }
+      });
+    };
+    buildGroup(sortedActive, true);
+    if (sortedPaused.length > 0) {
+      items.push({ type: 'paused-divider', count: sortedPaused.length });
+      buildGroup(sortedPaused, false);
+    }
+    return items;
+  }, [sortedActive, sortedPaused, subscriptionSort, collapsedGroups]);
+
+  const listRef = useRef(null);
+  const virtualizer = useVirtualizer({
+    count: flatVirtualItems?.length ?? 0,
+    getScrollElement: () => listRef.current,
+    estimateSize: i => {
+      if (!flatVirtualItems) return 96;
+      const it = flatVirtualItems[i];
+      if (it?.type === 'group-header') return 40;
+      if (it?.type === 'paused-divider') return 32;
+      return 96;
+    },
+    overscan: 5,
+    enabled: !!flatVirtualItems,
+  });
+
   async function persistSubscriptionOrder(nextSubscriptions, nextBills, movedId) {
+    const prevData = data;
+    const prevBills = bills;
     setData(prev => ({ ...prev, subscriptions: nextSubscriptions }));
     setBills(nextBills);
     setMovingBillId(movedId);
     try {
       await api.reorderBills(reorderPayload(nextBills));
-      toast.success('Subscription order saved');
       await load();
-      api.allBills().then(b => setBills(Array.isArray(b) ? b : [])).catch(err => console.error('[SubscriptionsPage] failed to refresh bills after reorder', err));
+      api.allBills().then(b => setBills(Array.isArray(b) ? b : [])).catch(() => {});
     } catch (err) {
       toast.error(err.message || 'Failed to save subscription order');
-      await load();
+      setData(prevData);
+      setBills(prevBills);
     } finally {
       setMovingBillId(null);
     }
@@ -1357,64 +1407,75 @@ export default function SubscriptionsPage() {
     return q ? highConfidenceRecs.filter(r => r.name?.toLowerCase().includes(q)) : highConfidenceRecs;
   }, [highConfidenceRecs, recSearch]);
 
-  function renderSubscriptionRows(group, activeState) {
-    if (subscriptionSort !== 'cadence') {
-      return group.map((item, index) => (
-        <SubscriptionRow
-          key={item.id}
-          item={item}
-          onEdit={bill => setModal({ bill })}
-          onToggle={toggleSubscription}
-          busy={busyId === `toggle-${item.id}`}
-          moveControls={moveControlsForGroup(group, activeState)(item, index)}
-          dragProps={dragPropsForGroup(group, activeState)(item, index)}
-        />
-      ));
-    }
-
-    return GROUP_ORDER.flatMap(groupKey => {
-      const groupItems = group.filter(item => subscriptionGroup(item) === groupKey);
-      if (groupItems.length === 0) return [];
-      const sectionKey = `${activeState ? 'active' : 'paused'}-${groupKey}`;
-      const isCollapsed = collapsedGroups.has(sectionKey);
-      const monthlySum = groupItems.reduce((s, i) => s + (Number(i.monthly_equivalent) || 0), 0);
-      return [
-        <button
-          key={`${sectionKey}-heading`}
-          type="button"
-          onClick={() => setCollapsedGroups(prev => {
-            const next = new Set(prev);
-            next.has(sectionKey) ? next.delete(sectionKey) : next.add(sectionKey);
-            return next;
-          })}
-          style={{ top: cardHeaderHeight }}
-          className="sticky z-10 w-full border-b border-t border-border/40 bg-card/95 backdrop-blur-sm px-4 py-2 text-left transition-colors hover:bg-muted/30"
-        >
-          <div className="flex items-center justify-between gap-3">
-            <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">
-              {GROUP_LABELS[groupKey]}
-            </p>
-            <div className="flex items-center gap-3">
-              <span className="text-[11px] font-medium text-muted-foreground tabular-nums">
-                {fmt(monthlySum)}/mo · {groupItems.length}
-              </span>
-              <ChevronDown className={cn('h-3.5 w-3.5 text-muted-foreground/60 transition-transform duration-150', isCollapsed && '-rotate-90')} />
-            </div>
+  function renderGroupHeader(sectionKey, groupKey, groupItems, monthlySum) {
+    const isCollapsed = collapsedGroups.has(sectionKey);
+    return (
+      <button
+        type="button"
+        onClick={() => setCollapsedGroups(prev => {
+          const next = new Set(prev);
+          next.has(sectionKey) ? next.delete(sectionKey) : next.add(sectionKey);
+          return next;
+        })}
+        style={{ top: cardHeaderHeight }}
+        className="sticky z-10 w-full border-b border-t border-border/40 bg-card/95 backdrop-blur-sm px-4 py-2 text-left transition-colors hover:bg-muted/30"
+      >
+        <div className="flex items-center justify-between gap-3">
+          <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">
+            {GROUP_LABELS[groupKey]}
+          </p>
+          <div className="flex items-center gap-3">
+            <span className="text-[11px] font-medium text-muted-foreground tabular-nums">
+              {fmt(monthlySum)}/mo · {groupItems.length}
+            </span>
+            <ChevronDown className={cn('h-3.5 w-3.5 text-muted-foreground/60 transition-transform duration-150', isCollapsed && '-rotate-90')} />
           </div>
-        </button>,
-        ...(!isCollapsed ? groupItems.map((item, index) => (
-          <SubscriptionRow
-            key={item.id}
-            item={item}
-            onEdit={bill => setModal({ bill })}
-            onToggle={toggleSubscription}
-            busy={busyId === `toggle-${item.id}`}
-            moveControls={moveControlsForGroup(groupItems, activeState)(item, index)}
-            dragProps={dragPropsForGroup(groupItems, activeState)(item, index)}
-          />
-        )) : []),
-      ];
-    });
+        </div>
+      </button>
+    );
+  }
+
+  // Custom sort: normal DOM rendering (drag-reorder needs DOM order)
+  function renderCustomRows(group, activeState) {
+    return group.map((item, index) => (
+      <SubscriptionRow
+        key={item.id}
+        item={item}
+        onEdit={bill => setModal({ bill })}
+        onToggle={toggleSubscription}
+        busy={false}
+        moveControls={moveControlsForGroup(group, activeState)(item, index)}
+        dragProps={dragPropsForGroup(group, activeState)(item, index)}
+      />
+    ));
+  }
+
+  // Cadence sort: virtualizer renders from flatVirtualItems
+  function renderVirtualItem(vRow) {
+    const it = flatVirtualItems[vRow.index];
+    if (!it) return null;
+    if (it.type === 'paused-divider') {
+      return (
+        <div className="border-t-2 border-border/60 bg-muted/20 px-4 py-1.5">
+          <p className="text-[10px] font-bold uppercase tracking-widest text-muted-foreground/60">
+            Paused · {it.count}
+          </p>
+        </div>
+      );
+    }
+    if (it.type === 'group-header') {
+      return renderGroupHeader(it.sectionKey, it.groupKey, it.groupItems, it.monthlySum);
+    }
+    return (
+      <SubscriptionRow
+        item={it.item}
+        onEdit={bill => setModal({ bill })}
+        onToggle={toggleSubscription}
+        busy={false}
+        moveControls={moveControlsForGroup(it.groupItems, it.activeState)(it.item, it.i)}
+        dragProps={dragPropsForGroup(it.groupItems, it.activeState)(it.item, it.i)}
+      />
+    );
   }
 
   return (
@@ -1513,7 +1574,7 @@ export default function SubscriptionsPage() {
               </div>
             </SearchFilterPanel>
           </CardHeader>
-          <CardContent className="p-0">
+          <CardContent className={cn('p-0', subscriptionSort === 'cadence' && 'max-h-[70vh] overflow-y-auto')}>
             {loading ? (
               <div className="p-4">
                 {Array.from({ length: 4 }).map((_, index) => (
@@ -1526,17 +1587,33 @@ export default function SubscriptionsPage() {
                 <p className="mt-3 text-sm font-medium">No subscriptions tracked yet.</p>
                 <p className="mt-1 text-sm text-muted-foreground">Add one manually or accept a SimpleFIN recommendation.</p>
               </div>
-            ) : (
-              <>
-                {renderSubscriptionRows(sortedActive, true)}
-                {sortedPaused.length > 0 && subscriptionSort === 'cadence' && (
-                  <div className="border-t-2 border-border/60 bg-muted/20 px-4 py-1.5">
-                    <p className="text-[10px] font-bold uppercase tracking-widest text-muted-foreground/60">
-                      Paused · {sortedPaused.length}
-                    </p>
+            ) : subscriptionSort === 'cadence' ? (
+              // Cadence mode: virtualised from flatVirtualItems
+              <div
+                ref={listRef}
+                style={{ height: virtualizer.getTotalSize(), position: 'relative' }}
+              >
+                {virtualizer.getVirtualItems().map(vRow => (
+                  <div
+                    key={vRow.key}
+                    data-index={vRow.index}
+                    ref={virtualizer.measureElement}
+                    style={{
+                      position: 'absolute',
+                      top: 0,
+                      width: '100%',
+                      transform: `translateY(${vRow.start}px)`,
+                    }}
+                  >
+                    {renderVirtualItem(vRow)}
                   </div>
-                )}
-                {renderSubscriptionRows(sortedPaused, false)}
+                ))}
+              </div>
+            ) : (
+              // Custom mode: normal DOM rendering so drag-reorder works
+              <>
+                {renderCustomRows(sortedActive, true)}
+                {renderCustomRows(sortedPaused, false)}
               </>
             )}
           </CardContent>