diff --git a/web/ui/app.js b/web/ui/app.js
index 3edeffe..9a4cac1 100644
--- a/web/ui/app.js
+++ b/web/ui/app.js
@@ -199,14 +199,20 @@ async function browseWavs() {
   const dir = document.getElementById('wav-dir').value;
   const list = document.getElementById('wav-list');
   list.innerHTML = 'Loading...';
+  console.log('browseWavs: dir =', dir);
 
   try {
-    const resp = await fetch(`${API}/list-wavs?dir=${encodeURIComponent(dir)}`);
+    const url = `${API}/list-wavs?dir=${encodeURIComponent(dir)}`;
+    console.log('browseWavs: fetching', url);
+    const resp = await fetch(url);
+    console.log('browseWavs: response status', resp.status, 'ok', resp.ok);
+
     if (!resp.ok) {
       list.innerHTML = '<span class="no-files">HTTP ' + resp.status + '</span>';
       return;
     }
     const data = await resp.json();
+    console.log('browseWavs: parsed data', data, 'type', typeof data, 'isArray', Array.isArray(data));
     if (!data || data.error) {
       list.innerHTML = '<span class="no-files">Error: ' + (data && data.error ? data.error : 'server error') + '</span>';
       return;
@@ -215,6 +221,7 @@ async function browseWavs() {
       list.innerHTML = '<span class="no-files">No WAV files found</span>';
       return;
     }
+    console.log('browseWavs: found', data.length, 'wavs');
     list.innerHTML = data.map(f => `
       <div class="wav-item" data-file="${esc(f)}">
         <span class="wav-name" title="${esc(f)}">${esc(f)}</span>
@@ -222,13 +229,16 @@ async function browseWavs() {
       </div>
     `).join('');
   } catch (e) {
+    console.error('browseWavs: error', e);
     list.innerHTML = 'Failed: ' + e.message;
   }
 }
 
 async function playWav(filename) {
+  console.log('playWav:', filename);
   if (!audioCtx) {
     audioCtx = new AudioContext();
+    console.log('playWav: created AudioContext');
   }
 
   if (currentSource) {