diff --git a/furumi-agent/src/web/admin.html b/furumi-agent/src/web/admin.html
index 35f9637..fd0117e 100644
--- a/furumi-agent/src/web/admin.html
+++ b/furumi-agent/src/web/admin.html
@@ -323,7 +323,11 @@ tr:hover td { background: var(--bg-hover); }
 </div>
 
 <script>
-const API = '/api';
+// Derive API base from current page path so it works behind any reverse-proxy prefix
+// e.g. page at "/admin" or "/admin/" → API = "/admin/api"
+// e.g. page at "/" → API = "/api"
+const _base = location.pathname.replace(/\/+$/, '');
+const API = _base + '/api';
 let currentTab = 'queue';
 let currentFilter = null;
 
diff --git a/furumi-web-player/src/web/player.html b/furumi-web-player/src/web/player.html
index 631297c..3aa8b63 100644
--- a/furumi-web-player/src/web/player.html
+++ b/furumi-web-player/src/web/player.html
@@ -250,8 +250,10 @@ audio.addEventListener('pause', () => document.getElementById('btnPlayPause').in
 audio.addEventListener('error', () => { showToast('Playback error'); nextTrack(); });
 
 // --- API helper ---
+const _base = location.pathname.replace(/\/+$/, '');
+const API = _base + '/api';
 async function api(path) {
-  const r = await fetch('/api' + path);
+  const r = await fetch(API + path);
   if (!r.ok) return null;
   return r.json();
 }
@@ -323,7 +325,7 @@ async function showAlbumTracks(albumSlug, albumName, artistSlug, artistName) {
   allBtn.onclick = () => addAlbumToQueue(albumSlug, true);
   el.appendChild(allBtn);
 
-  const coverUrl = '/api/albums/' + albumSlug + '/cover';
+  const coverUrl = API + '/albums/' + albumSlug + '/cover';
 
   tracks.forEach(t => {
     const div = document.createElement('div');
@@ -392,7 +394,7 @@ function playIndex(i) {
   if (i < 0 || i >= queue.length) return;
   queueIndex = i;
   const track = queue[i];
-  audio.src = '/api/stream/' + track.slug;
+  audio.src = API + '/stream/' + track.slug;
   audio.play().catch(() => {});
   updateNowPlaying(track);
   renderQueue();
@@ -407,7 +409,7 @@ function updateNowPlaying(track) {
   document.title = track.title + ' \u2014 Furumi';
 
   const cover = document.getElementById('npCover');
-  const coverUrl = '/api/tracks/' + track.slug + '/cover';
+  const coverUrl = API + '/tracks/' + track.slug + '/cover';
   cover.innerHTML = `<img src="${coverUrl}" alt="" onerror="this.parentElement.innerHTML='&#127925;'">`;
 
   if ('mediaSession' in navigator) {
@@ -434,7 +436,7 @@ function renderQueue() {
     const div = document.createElement('div');
     div.className = 'queue-item' + (isPlaying ? ' playing' : '');
 
-    const coverSrc = t.album_slug ? `/api/tracks/${t.slug}/cover` : '';
+    const coverSrc = t.album_slug ? `${API}/tracks/${t.slug}/cover` : '';
     const coverHtml = coverSrc
       ? `<img src="${coverSrc}" alt="" onerror="this.parentElement.innerHTML='&#127925;'">`
       : '&#127925;';