diff --git a/frontends/ycdl_flask/backend/endpoints/channel_endpoints.py b/frontends/ycdl_flask/backend/endpoints/channel_endpoints.py
index 7d97768..0725958 100644
--- a/frontends/ycdl_flask/backend/endpoints/channel_endpoints.py
+++ b/frontends/ycdl_flask/backend/endpoints/channel_endpoints.py
@@ -147,6 +147,7 @@ def post_refresh_all_channels():
     common.ycdldb.refresh_all_channels(force=force, skip_failures=True, commit=True)
     return flasktools.json_response({})
 
+@flasktools.required_fields(['state'], forbid_whitespace=True)
 @site.route('/channel/<channel_id>/set_automark', methods=['POST'])
 def post_set_automark(channel_id):
     state = request.form['state']
@@ -173,6 +174,7 @@ def post_set_autorefresh(channel_id):
 
     return flasktools.json_response({})
 
+@flasktools.required_fields(['download_directory'], forbid_whitespace=False)
 @site.route('/channel/<channel_id>/set_download_directory', methods=['POST'])
 def post_set_download_directory(channel_id):
     download_directory = request.form['download_directory']
@@ -202,6 +204,7 @@ def post_set_name(channel_id):
     response = {'name': channel.name}
     return flasktools.json_response(response)
 
+@flasktools.required_fields(['extension'], forbid_whitespace=False)
 @site.route('/channel/<channel_id>/set_queuefile_extension', methods=['POST'])
 def post_set_queuefile_extension(channel_id):
     extension = request.form['extension']
diff --git a/frontends/ycdl_flask/backend/endpoints/video_endpoints.py b/frontends/ycdl_flask/backend/endpoints/video_endpoints.py
index 64fdf33..3eaa248 100644
--- a/frontends/ycdl_flask/backend/endpoints/video_endpoints.py
+++ b/frontends/ycdl_flask/backend/endpoints/video_endpoints.py
@@ -8,10 +8,9 @@ from .. import common
 
 site = common.site
 
+@flasktools.required_fields(['video_ids', 'state'], forbid_whitespace=True)
 @site.route('/mark_video_state', methods=['POST'])
 def post_mark_video_state():
-    if 'video_ids' not in request.form or 'state' not in request.form:
-        flask.abort(400)
     video_ids = request.form['video_ids']
     state = request.form['state']
     try:
@@ -31,10 +30,9 @@ def post_mark_video_state():
 
     return flasktools.json_response({'video_ids': video_ids, 'state': state})
 
+@flasktools.required_fields(['video_ids'], forbid_whitespace=True)
 @site.route('/start_download', methods=['POST'])
 def post_start_download():
-    if 'video_ids' not in request.form:
-        flask.abort(400)
     video_ids = request.form['video_ids']
     try:
         video_ids = video_ids.split(',')