diff --git a/common.py b/common.py
index 8a9c30a..bc8ff6c 100644
--- a/common.py
+++ b/common.py
@@ -93,7 +93,8 @@ DOMAINS = (PRIMARY_DOMAIN,) + OTHER_DOMAINS
 
 
 def not_5xx(resp):
-    return isinstance(resp, tuple) and resp[1] // 100 != 5
+    return (isinstance(resp, tuple) and len(resp) > 1 and util.is_int(resp[1]) and
+            resp[1] // 100 != 5)
 
 
 def requests_get(url, **kwargs):
diff --git a/tests/test_models.py b/tests/test_models.py
index b977729..14f42c4 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -1,5 +1,6 @@
 # coding=utf-8
 """Unit tests for models.py."""
+from app import app
 from models import MagicKey, Response
 from . import testutil
 
@@ -52,9 +53,10 @@ class ResponseTest(testutil.TestCase):
         self.assertEqual('abc__1 xyz__Z', resp.key.id())
 
     def test_proxy_url(self):
-        resp = Response.get_or_create('abc', 'xyz')
-        self.assertIsNone(resp.proxy_url(self.handler))
+        with app.test_request_context('/'):
+            resp = Response.get_or_create('abc', 'xyz')
+            self.assertIsNone(resp.proxy_url())
 
-        resp.source_as2 = 'as2'
-        self.assertEqual('http://localhost/render?source=abc&target=xyz',
-                          resp.proxy_url(self.handler))
+            resp.source_as2 = 'as2'
+            self.assertEqual('http://localhost/render?source=abc&target=xyz',
+                             resp.proxy_url())
diff --git a/tests/test_webfinger.py b/tests/test_webfinger.py
index 56e5a6a..7787dc1 100644
--- a/tests/test_webfinger.py
+++ b/tests/test_webfinger.py
@@ -94,8 +94,7 @@ class WebfingerTest(testutil.TestCase):
     def test_host_meta_handler_xrds(self):
         got = client.get('/.well-known/host-meta.xrds')
         self.assertEqual(200, got.status_code)
-        self.assertEqual('application/xrds+xml; charset=utf-8',
-                          got.headers['Content-Type'])
+        self.assertEqual('application/xrds+xml', got.headers['Content-Type'])
         body = got.get_data(as_text=True)
         self.assertTrue(body.startswith('<XRDS'), body)
 
diff --git a/webfinger.py b/webfinger.py
index e1a9f02..5cbbac3 100644
--- a/webfinger.py
+++ b/webfinger.py
@@ -174,5 +174,29 @@ class Webfinger(User):
         return super().template_vars(domain=domain, url=url)
 
 
+class HostMeta(common.XrdOrJrd):
+    """Renders and serves the /.well-known/host-meta file.
+
+    Supports both JRD and XRD; defaults to XRD.
+    https://tools.ietf.org/html/rfc6415#section-3
+    """
+    DEFAULT_TYPE = common.XrdOrJrd.XRD
+
+    def template_prefix(self):
+        return 'host-meta'
+
+    def template_vars(self):
+        return {'host_uri': request.host_url}
+
+
+@app.get('/.well-known/host-meta.xrds')
+def host_meta_xrds():
+    """Renders and serves the /.well-known/host-meta.xrds XRDS-Simple file."""
+    return (render_template('host-meta.xrds', host_uri=request.host_url),
+            {'Content-Type': 'application/xrds+xml'})
+
+
 app.add_url_rule('/acct:<domain>', view_func=User.as_view('user'))
 app.add_url_rule('/.well-known/webfinger', view_func=Webfinger.as_view('webfinger'))
+app.add_url_rule('/.well-known/host-meta', view_func=HostMeta.as_view('hostmeta'))
+app.add_url_rule('/.well-known/host-meta.json', view_func=HostMeta.as_view('hostmeta-json'))