diff --git a/Dockerfile b/Dockerfile
index 82249ad..556e65e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -35,3 +35,8 @@ EXPOSE 8030
 # Single worker: the in-memory JOBS registry must live in one process.
 # Threads give concurrency while conversions run in their own worker threads.
 CMD ["sh", "-c", "gunicorn app:app --bind 0.0.0.0:${PORT} --workers 1 --threads 8 --timeout 1200 --graceful-timeout 30 --access-logfile - --error-logfile -"]
+
+# Health probe: pure-python urllib (slim image has no curl/wget).
+# Coolify detects this and skips its own curl/wget-based check. Kept as the final line
+# because Coolify's parser appends the following line to the HEALTHCHECK command.
+HEALTHCHECK --interval=30s --timeout=10s --start-period=30s --retries=3 CMD python -c "import urllib.request,sys; sys.exit(0 if urllib.request.urlopen('http://127.0.0.1:8030/health', timeout=5).status==200 else 1)"