diff --git a/extension/src/popup/components/item-list.ts b/extension/src/popup/components/item-list.ts
index f46b7ba..ae15f9d 100644
--- a/extension/src/popup/components/item-list.ts
+++ b/extension/src/popup/components/item-list.ts
@@ -3,6 +3,7 @@
 /// to the detail view.
 
 import { getState, setState, sendMessage, navigate, escapeHtml, openVaultTab } from '../../shared/state';
+import { showToast } from '../../shared/toast';
 import {
   GLYPH_VAULT_TAB,
   GLYPH_DEVICES, GLYPH_LOCK,
@@ -130,11 +131,14 @@ export function renderItemList(app: HTMLElement): void {
       if (listResp.ok) {
         const data = listResp.data as { items: Array<[ItemId, ManifestEntry]> };
         setState({ entries: data.items, loading: false });
+        showToast('Synced', 'success');
         return;
       }
       setState({ loading: false, error: listResp.error });
+      showToast(listResp.error ?? 'Sync failed', 'error');
     } else {
       setState({ loading: false, error: resp.error });
+      showToast(resp.error ?? 'Sync failed', 'error');
     }
   });
 
diff --git a/extension/src/popup/styles.css b/extension/src/popup/styles.css
index ad64c1c..ee28b08 100644
--- a/extension/src/popup/styles.css
+++ b/extension/src/popup/styles.css
@@ -1660,4 +1660,42 @@ textarea {
 
 .type-card__icon  { font-size: 20px; margin-bottom: 4px; }
 .type-card__label { font-size: 12px; font-weight: 600; }
+
+/* Toast notifications */
+.relicario-toast-container {
+  position: fixed;
+  bottom: 16px;
+  left: 50%;
+  transform: translateX(-50%);
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  pointer-events: none;
+  z-index: 9999;
+}
+
+.vault-shell .relicario-toast-container {
+  left: auto;
+  right: 24px;
+  transform: none;
+}
+
+.relicario-toast {
+  padding: 8px 16px;
+  border-radius: 6px;
+  font-size: 12px;
+  opacity: 0;
+  transform: translateY(8px);
+  transition: opacity 0.2s, transform 0.2s;
+  pointer-events: none;
+}
+
+.relicario-toast--visible {
+  opacity: 1;
+  transform: translateY(0);
+}
+
+.relicario-toast--success { background: #1f4a24; color: #aff0b5; border: 1px solid #238636; }
+.relicario-toast--error   { background: #4a1f1f; color: #f0afaf; border: 1px solid #ab2b20; }
+.relicario-toast--info    { background: #1f2d4a; color: #afc8f0; border: 1px solid #1f6feb; }
 .type-card__desc  { font-size: 10px; color: var(--text-muted, #8b949e); margin-top: 2px; }
diff --git a/extension/src/shared/toast.ts b/extension/src/shared/toast.ts
new file mode 100644
index 0000000..943ea09
--- /dev/null
+++ b/extension/src/shared/toast.ts
@@ -0,0 +1,26 @@
+export function showToast(
+  message: string,
+  type: 'success' | 'error' | 'info' = 'info',
+  durationMs = 2500,
+): void {
+  let container = document.querySelector<HTMLElement>('.relicario-toast-container');
+  if (!container) {
+    container = document.createElement('div');
+    container.className = 'relicario-toast-container';
+    document.body.appendChild(container);
+  }
+
+  const toast = document.createElement('div');
+  toast.className = `relicario-toast relicario-toast--${type}`;
+  toast.textContent = message;
+  container.appendChild(toast);
+
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => toast.classList.add('relicario-toast--visible'));
+  });
+
+  setTimeout(() => {
+    toast.classList.remove('relicario-toast--visible');
+    toast.addEventListener('transitionend', () => toast.remove(), { once: true });
+  }, durationMs);
+}
diff --git a/extension/src/vault/vault.css b/extension/src/vault/vault.css
index c1d1639..270b73b 100644
--- a/extension/src/vault/vault.css
+++ b/extension/src/vault/vault.css
@@ -1719,3 +1719,41 @@ textarea {
   background: linear-gradient(to top, rgba(17, 22, 30, 0.7), transparent);
   pointer-events: none;
 }
+
+/* Toast notifications */
+.relicario-toast-container {
+  position: fixed;
+  bottom: 16px;
+  left: 50%;
+  transform: translateX(-50%);
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  pointer-events: none;
+  z-index: 9999;
+}
+
+.vault-shell .relicario-toast-container {
+  left: auto;
+  right: 24px;
+  transform: none;
+}
+
+.relicario-toast {
+  padding: 8px 16px;
+  border-radius: 6px;
+  font-size: 12px;
+  opacity: 0;
+  transform: translateY(8px);
+  transition: opacity 0.2s, transform 0.2s;
+  pointer-events: none;
+}
+
+.relicario-toast--visible {
+  opacity: 1;
+  transform: translateY(0);
+}
+
+.relicario-toast--success { background: #1f4a24; color: #aff0b5; border: 1px solid #238636; }
+.relicario-toast--error   { background: #4a1f1f; color: #f0afaf; border: 1px solid #ab2b20; }
+.relicario-toast--info    { background: #1f2d4a; color: #afc8f0; border: 1px solid #1f6feb; }