diff --git a/tools/make-chromium-meta.py b/tools/make-chromium-meta.py
index 319b7a1d7..5388e50f5 100644
--- a/tools/make-chromium-meta.py
+++ b/tools/make-chromium-meta.py
@@ -23,7 +23,7 @@ with open(manifest_out_file) as f:
 manifest_out['version'] = version
 
 # Development build? If so, modify name accordingly.
-match = re.search('^\d+\.\d+\.\d+\.\d+$', version)
+match = re.search(r'^\d+\.\d+\.\d+\.\d+$', version)
 if match:
     manifest_out['name'] += ' development build'
     manifest_out['short_name'] += ' dev build'
diff --git a/tools/make-firefox-meta.py b/tools/make-firefox-meta.py
index fa4ed7107..e10f91065 100644
--- a/tools/make-firefox-meta.py
+++ b/tools/make-firefox-meta.py
@@ -21,7 +21,7 @@ with open(firefox_manifest_file) as f2:
     firefox_manifest = json.load(f2)
 
 if 'sidebar_action' in firefox_manifest:
-    match = re.search('^(\d+\.\d+\.\d+)(\.\d+)$', version)
+    match = re.search(r'^(\d+\.\d+\.\d+)(\.\d+)$', version)
     if not match:
         # https://bugzilla.mozilla.org/show_bug.cgi?id=1459007
         # By design Firefox opens the sidebar with new installation of