diff --git a/worker.php b/worker.php
index ea5a11d..d8f3a0c 100644
--- a/worker.php
+++ b/worker.php
@@ -51,7 +51,14 @@ $generator = new \Web2Print\Services\PdfGenerator($config);
 $pdfPath = $jobs->pdfPath($jobId);
 
 $pageCount = 0;
-$onProgress = function (string $line) use ($jobs, $jobId, &$pageCount) {
+$debugLog = $config['log_file'];
+$logLine = function (string $msg) use ($debugLog, $jobId) {
+    @file_put_contents($debugLog, '[' . date('Y-m-d H:i:s.u') . '] [job ' . $jobId . '] ' . $msg . "\n", FILE_APPEND);
+};
+$logLine('worker start, url=' . ($request['url'] ?? '?'));
+
+$onProgress = function (string $line) use ($jobs, $jobId, &$pageCount, $logLine) {
+    $logLine('stdout: ' . $line);
     // pagedjs-cli utilise ora qui peut émettre via \r ; on a déjà découpé.
     // Lignes typiques : "- Loading: ...", "✔ Loaded", "- Rendering: Page X"
     if (preg_match('/Rendering:\s*Page\s*(\d+)/i', $line, $m)) {