diff --git a/jupyterlab/labapp.py b/jupyterlab/labapp.py
index 32bba4f524d0..4ef81e1ca8ae 100644
--- a/jupyterlab/labapp.py
+++ b/jupyterlab/labapp.py
@@ -61,8 +61,8 @@ class LabBuildApp(JupyterApp, DebugLogFileMixin):
     version = Unicode('', config=True,
         help="The version of the built application")
 
-    dev_build = Bool(True, config=True,
-        help="Whether to build in dev mode (defaults to dev mode)")
+    dev_build = Bool(False, config=True,
+        help="Whether to build in dev mode (defaults to prod mode)")
 
     pre_clean = Bool(False, config=True,
         help="Whether to clean before building (defaults to False)")
diff --git a/jupyterlab/labextensions.py b/jupyterlab/labextensions.py
index 09b6802b3b0e..54f8a654c0d9 100644
--- a/jupyterlab/labextensions.py
+++ b/jupyterlab/labextensions.py
@@ -69,8 +69,8 @@ class BaseExtensionApp(JupyterApp, DebugLogFileMixin):
     should_build = Bool(True, config=True,
         help="Whether to build the app after the action")
 
-    dev_build = Bool(True, config=True,
-        help="Whether to build in dev mode (defaults to dev mode)")
+    dev_build = Bool(False, config=True,
+        help="Whether to build in dev mode (defaults to prod mode)")
 
     should_clean = Bool(False, config=True,
         help="Whether temporary files should be cleaned up after building jupyterlab")