diff --git a/account/urls/admin.py b/account/urls/admin.py
index 372ba244..b10741eb 100644
--- a/account/urls/admin.py
+++ b/account/urls/admin.py
@@ -3,5 +3,5 @@ from django.conf.urls import url
 from ..views.admin import UserAdminAPI
 
 urlpatterns = [
-    url(r"^user$", UserAdminAPI.as_view(), name="user_admin_api"),
+    url(r"^user/?$", UserAdminAPI.as_view(), name="user_admin_api"),
 ]
diff --git a/account/urls/oj.py b/account/urls/oj.py
index 1a663399..e73311f8 100644
--- a/account/urls/oj.py
+++ b/account/urls/oj.py
@@ -7,9 +7,9 @@ from ..views.oj import (UserChangePasswordAPI, UserLoginAPI, UserRegisterAPI,
                         ApplyResetPasswordAPI, ResetPasswordAPI)
 
 urlpatterns = [
-    url(r"^login$", UserLoginAPI.as_view(), name="user_login_api"),
-    url(r"^register$", UserRegisterAPI.as_view(), name="user_register_api"),
-    url(r"^change_password$", UserChangePasswordAPI.as_view(), name="user_change_password_api"),
-    url(r"^apply_reset_password$", ApplyResetPasswordAPI.as_view(), name="apply_reset_password_api"),
-    url(r"^reset_password$", ResetPasswordAPI.as_view(), name="apply_reset_password_api")
+    url(r"^login/?$", UserLoginAPI.as_view(), name="user_login_api"),
+    url(r"^register/?$", UserRegisterAPI.as_view(), name="user_register_api"),
+    url(r"^change_password/?$", UserChangePasswordAPI.as_view(), name="user_change_password_api"),
+    url(r"^apply_reset_password/?$", ApplyResetPasswordAPI.as_view(), name="apply_reset_password_api"),
+    url(r"^reset_password/?$", ResetPasswordAPI.as_view(), name="apply_reset_password_api")
 ]
diff --git a/account/urls/user.py b/account/urls/user.py
index 3eb9252c..3ec765af 100644
--- a/account/urls/user.py
+++ b/account/urls/user.py
@@ -7,9 +7,9 @@ from ..views.user import (UserInfoAPI, UserProfileAPI, AvatarUploadAPI,
                           SSOAPI, TwoFactorAuthAPI)
 
 urlpatterns = [
-    url(r"^user$", UserInfoAPI.as_view(), name="user_info_api"),
-    url(r"^profile$", UserProfileAPI.as_view(), name="user_profile_api"),
-    url(r"^avatar/upload$", AvatarUploadAPI.as_view(), name="avatar_upload_api"),
-    url(r"^sso$", SSOAPI.as_view(), name="sso_api"),
-    url(r"^two_factor_auth$", TwoFactorAuthAPI.as_view(), name="two_factor_auth_api")
+    url(r"^user/?$", UserInfoAPI.as_view(), name="user_info_api"),
+    url(r"^profile/?$", UserProfileAPI.as_view(), name="user_profile_api"),
+    url(r"^avatar/upload/?$", AvatarUploadAPI.as_view(), name="avatar_upload_api"),
+    url(r"^sso/?$", SSOAPI.as_view(), name="sso_api"),
+    url(r"^two_factor_auth/?$", TwoFactorAuthAPI.as_view(), name="two_factor_auth_api")
 ]
diff --git a/account/views/user.py b/account/views/user.py
index 7cbd7911..d3bcacfa 100644
--- a/account/views/user.py
+++ b/account/views/user.py
@@ -122,9 +122,9 @@ class TwoFactorAuthAPI(APIView):
         config = WebsiteConfig.objects.first()
         image = qrcode.make(OtpAuth(token).to_uri("totp", config.base_url, config.name))
         buf = StringIO()
-        image.save(buf, 'gif')
+        image.save(buf, "gif")
 
-        return HttpResponse(buf.getvalue(), 'image/gif')
+        return HttpResponse(buf.getvalue(), "image/gif")
 
     @login_required
     @validate_serializer(TwoFactorAuthCodeSerializer)
diff --git a/announcement/urls/admin.py b/announcement/urls/admin.py
index fefc160d..6b9ce0f8 100644
--- a/announcement/urls/admin.py
+++ b/announcement/urls/admin.py
@@ -3,5 +3,5 @@ from django.conf.urls import url
 from ..views import AnnouncementAdminAPI
 
 urlpatterns = [
-    url(r"^announcement$", AnnouncementAdminAPI.as_view(), name="announcement_admin_api"),
+    url(r"^announcement/?$", AnnouncementAdminAPI.as_view(), name="announcement_admin_api"),
 ]
diff --git a/conf/urls/admin.py b/conf/urls/admin.py
index dcb5c6fc..be242723 100644
--- a/conf/urls/admin.py
+++ b/conf/urls/admin.py
@@ -3,7 +3,7 @@ from django.conf.urls import url
 from ..views import SMTPAPI, JudgeServerAPI, WebsiteConfigAPI
 
 urlpatterns = [
-    url(r"^smtp$", SMTPAPI.as_view(), name="smtp_admin_api"),
-    url(r"^website$", WebsiteConfigAPI.as_view(), name="website_config_api"),
-    url(r"^judge_server", JudgeServerAPI.as_view(), name="judge_server_api")
+    url(r"^smtp/?$", SMTPAPI.as_view(), name="smtp_admin_api"),
+    url(r"^website/?$", WebsiteConfigAPI.as_view(), name="website_config_api"),
+    url(r"^judge_server/?$", JudgeServerAPI.as_view(), name="judge_server_api")
 ]
diff --git a/conf/urls/oj.py b/conf/urls/oj.py
index b5a06e5b..3e6d7578 100644
--- a/conf/urls/oj.py
+++ b/conf/urls/oj.py
@@ -3,7 +3,7 @@ from django.conf.urls import url
 from ..views import JudgeServerHeartbeatAPI, LanguagesAPI, WebsiteConfigAPI
 
 urlpatterns = [
-    url(r"^website$", WebsiteConfigAPI.as_view(), name="website_info_api"),
-    url(r"^judge_server_heartbeat$", JudgeServerHeartbeatAPI.as_view(), name="judge_server_heartbeat_api"),
-    url(r"^languages$", LanguagesAPI.as_view(), name="language_list_api")
+    url(r"^website/?$", WebsiteConfigAPI.as_view(), name="website_info_api"),
+    url(r"^judge_server_heartbeat/?$", JudgeServerHeartbeatAPI.as_view(), name="judge_server_heartbeat_api"),
+    url(r"^languages/?$", LanguagesAPI.as_view(), name="language_list_api")
 ]
diff --git a/contest/urls/admin.py b/contest/urls/admin.py
index d9ea9c9d..2a7705a7 100644
--- a/contest/urls/admin.py
+++ b/contest/urls/admin.py
@@ -3,6 +3,6 @@ from django.conf.urls import url
 from ..views.admin import ContestAnnouncementAPI, ContestAPI
 
 urlpatterns = [
-    url(r"^contest$", ContestAPI.as_view(), name="contest_api"),
-    url(r"^contest/announcement$", ContestAnnouncementAPI.as_view(), name="contest_announcement_admin_api")
+    url(r"^contest/?$", ContestAPI.as_view(), name="contest_api"),
+    url(r"^contest/announcement/?$", ContestAnnouncementAPI.as_view(), name="contest_announcement_admin_api")
 ]
diff --git a/contest/urls/oj.py b/contest/urls/oj.py
index e2e48cac..bfc80b8a 100644
--- a/contest/urls/oj.py
+++ b/contest/urls/oj.py
@@ -3,5 +3,5 @@ from django.conf.urls import url
 from ..views.oj import ContestAnnouncementListAPI
 
 urlpatterns = [
-    url(r"^contest$", ContestAnnouncementListAPI.as_view(), name="contest_list_api"),
+    url(r"^contest/?$", ContestAnnouncementListAPI.as_view(), name="contest_list_api"),
 ]
diff --git a/problem/urls/admin.py b/problem/urls/admin.py
index bfd66c22..7ea423e8 100644
--- a/problem/urls/admin.py
+++ b/problem/urls/admin.py
@@ -3,7 +3,7 @@ from django.conf.urls import url
 from ..views.admin import ProblemAPI, TestCaseUploadAPI, ContestProblemAPI
 
 urlpatterns = [
-    url(r"^test_case/upload$", TestCaseUploadAPI.as_view(), name="test_case_upload_api"),
-    url(r"^problem$", ProblemAPI.as_view(), name="problem_api"),
-    url(r"^contest/problem$", ContestProblemAPI.as_view(), name="contest_problem_api")
+    url(r"^test_case/upload/?$", TestCaseUploadAPI.as_view(), name="test_case_upload_api"),
+    url(r"^problem/?$", ProblemAPI.as_view(), name="problem_api"),
+    url(r"^contest/problem/?$", ContestProblemAPI.as_view(), name="contest_problem_api")
 ]
diff --git a/problem/urls/oj.py b/problem/urls/oj.py
index d99155a6..a7613f12 100644
--- a/problem/urls/oj.py
+++ b/problem/urls/oj.py
@@ -3,5 +3,5 @@ from django.conf.urls import url
 from ..views.oj import ProblemTagAPI
 
 urlpatterns = [
-    url(r"^problem/tags$", ProblemTagAPI.as_view(), name="problem_tag_list_api")
+    url(r"^problem/tags/?$", ProblemTagAPI.as_view(), name="problem_tag_list_api")
 ]