diff --git a/datasette/app.py b/datasette/app.py
index fe461d42..cdfcb11d 100644
--- a/datasette/app.py
+++ b/datasette/app.py
@@ -468,7 +468,7 @@ class Datasette:
         self.jinja_env.filters["escape_sqlite"] = escape_sqlite
         self.jinja_env.filters["to_css_class"] = to_css_class
         pm.hook.prepare_jinja2_environment(env=self.jinja_env)
-        app.add_route(IndexView.as_view(self), "/<as_format:(\.jsono?)?$>")
+        app.add_route(IndexView.as_view(self), r"/<as_format:(\.jsono?)?$>")
         # TODO: /favicon.ico and /-/static/ deserve far-future cache expires
         app.add_route(favicon, "/favicon.ico")
         app.static("/-/static/", str(app_root / "datasette" / "static"))
@@ -481,37 +481,37 @@ class Datasette:
                 app.static(modpath, plugin["static_path"])
         app.add_route(
             JsonDataView.as_view(self, "inspect.json", self.inspect),
-            "/-/inspect<as_format:(\.json)?$>",
+            r"/-/inspect<as_format:(\.json)?$>",
         )
         app.add_route(
             JsonDataView.as_view(self, "metadata.json", lambda: self._metadata),
-            "/-/metadata<as_format:(\.json)?$>",
+            r"/-/metadata<as_format:(\.json)?$>",
         )
         app.add_route(
             JsonDataView.as_view(self, "versions.json", self.versions),
-            "/-/versions<as_format:(\.json)?$>",
+            r"/-/versions<as_format:(\.json)?$>",
         )
         app.add_route(
             JsonDataView.as_view(self, "plugins.json", self.plugins),
-            "/-/plugins<as_format:(\.json)?$>",
+            r"/-/plugins<as_format:(\.json)?$>",
         )
         app.add_route(
             JsonDataView.as_view(self, "config.json", lambda: self._config),
-            "/-/config<as_format:(\.json)?$>",
+            r"/-/config<as_format:(\.json)?$>",
         )
         app.add_route(
-            DatabaseDownload.as_view(self), "/<db_name:[^/]+?><as_db:(\.db)$>"
+            DatabaseDownload.as_view(self), r"/<db_name:[^/]+?><as_db:(\.db)$>"
         )
         app.add_route(
-            DatabaseView.as_view(self), "/<db_name:[^/]+?><as_format:(\.jsono?|\.csv)?$>"
+            DatabaseView.as_view(self), r"/<db_name:[^/]+?><as_format:(\.jsono?|\.csv)?$>"
         )
         app.add_route(
             TableView.as_view(self),
-            "/<db_name:[^/]+>/<table_and_format:[^/]+?$>",
+            r"/<db_name:[^/]+>/<table_and_format:[^/]+?$>",
         )
         app.add_route(
             RowView.as_view(self),
-            "/<db_name:[^/]+>/<table:[^/]+?>/<pk_path:[^/]+?><as_format:(\.jsono?)?$>",
+            r"/<db_name:[^/]+>/<table:[^/]+?>/<pk_path:[^/]+?><as_format:(\.jsono?)?$>",
         )
         self.register_custom_units()
         # On 404 with a trailing slash redirect to path without that slash:
diff --git a/tests/test_html.py b/tests/test_html.py
index 41af9b25..913eac94 100644
--- a/tests/test_html.py
+++ b/tests/test_html.py
@@ -687,7 +687,7 @@ def test_allow_download_on(app_client):
         "/fixtures"
     )
     soup = Soup(response.body, 'html.parser')
-    assert len(soup.findAll('a', {'href': re.compile('\.db$')}))
+    assert len(soup.findAll('a', {'href': re.compile(r'\.db$')}))
 
 
 def test_allow_download_off():
@@ -699,7 +699,7 @@ def test_allow_download_off():
 
         )
         soup = Soup(response.body, 'html.parser')
-        assert not len(soup.findAll('a', {'href': re.compile('\.db$')}))
+        assert not len(soup.findAll('a', {'href': re.compile(r'\.db$')}))
         # Accessing URL directly should 403
         response = client.get(
             "/fixtures.db",