diff --git a/__init__.py b/__init__.py
index 52b60e2..84adcf5 100644
--- a/__init__.py
+++ b/__init__.py
@@ -258,7 +258,7 @@ async def _run_server(cert_file, key_file):
     ssl_ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
     ssl_ctx.load_cert_chain(cert_file, key_file)
 
-    app = web.Application()
+    app = web.Application(client_max_size=512 * 1024 * 1024)  # 512MB
     app.router.add_route('*', '/',              handle_request)
     app.router.add_route('*', '/{path_info:.*}', handle_request)