diff --git a/app/Controllers/Home.php b/app/Controllers/Home.php
index 95e2d98..05a6d8a 100644
--- a/app/Controllers/Home.php
+++ b/app/Controllers/Home.php
@@ -259,8 +259,33 @@ class Home extends BaseController
         }
 
         $file = $this->request->getFile('audio');
-        if ($file === null || ! $file->isValid()) {
-            return $this->response->setStatusCode(400)->setJSON(['error' => 'No valid audio file received']);
+        if ($file === null) {
+            // Fallback key for compatibility with alternate STT clients.
+            $file = $this->request->getFile('file');
+        }
+
+        if ($file === null) {
+            return $this->response->setStatusCode(400)->setJSON([
+                'error' => 'No audio file received',
+                'expected_field' => 'audio',
+            ]);
+        }
+
+        if (! $file->isValid()) {
+            return $this->response->setStatusCode(400)->setJSON([
+                'error' => 'Invalid uploaded audio file',
+                'upload_error_code' => $file->getError(),
+                'upload_error' => $file->getErrorString(),
+                'upload_max_filesize' => (string) ini_get('upload_max_filesize'),
+                'post_max_size' => (string) ini_get('post_max_size'),
+            ]);
+        }
+
+        $fileSize = (int) $file->getSize();
+        if ($fileSize <= 0) {
+            return $this->response->setStatusCode(400)->setJSON([
+                'error' => 'Empty audio received',
+            ]);
         }
 
         $lang    = (string) ($this->request->getPost('lang') ?? 'en-IN');
@@ -294,7 +319,7 @@ class Home extends BaseController
                 ->setJSON(['error' => 'STT server unreachable', 'detail' => $curlErr]);
         }
 
-        $decoded = json_decode($body, true);
+        $decoded = json_decode((string) $body, true);
         if ($decoded === null) {
             return $this->response->setStatusCode(502)
                 ->setJSON(['error' => 'Invalid response from STT server']);
diff --git a/app/Views/billing/opd_prescription_basic.php b/app/Views/billing/opd_prescription_basic.php
index 2532835..eb44cd2 100644
--- a/app/Views/billing/opd_prescription_basic.php
+++ b/app/Views/billing/opd_prescription_basic.php
@@ -1207,6 +1207,11 @@
                 medicalSttTarget = '';
                 setMedicalMicButtonState('');
 
+                if (!blob || !blob.size || blob.size < 1024) {
+                    $('.jsError').removeClass('text-success text-muted').addClass('text-danger').text('Recording too short. Please record for at least 1-2 seconds.');
+                    return;
+                }
+
                 sendMedicalAudioToServer(blob, targetForTranscript).then(function(transcript) {
                     appendTranscriptToField(targetForTranscript, transcript);
                     $('.jsError').removeClass('text-danger text-muted').addClass('text-success').text('Medical speech text added.');
@@ -1361,6 +1366,11 @@
                 stopComplaintsMediaStream();
                 setComplaintsMicListening(false);
 
+                if (!blob || !blob.size || blob.size < 1024) {
+                    $('.jsError').removeClass('text-success text-muted').addClass('text-danger').text('Recording too short. Please record for at least 1-2 seconds.');
+                    return;
+                }
+
                 sendComplaintsAudioToServer(blob).then(function(transcript) {
                     appendTranscriptToComplaints(transcript);
                     $('.jsError').removeClass('text-danger text-muted').addClass('text-success').text('Complaints speech text added.');