diff --git a/ddportfolioservice/model/urlbuilder.py b/ddportfolioservice/model/urlbuilder.py
index 462f241..72db643 100644
--- a/ddportfolioservice/model/urlbuilder.py
+++ b/ddportfolioservice/model/urlbuilder.py
@@ -50,9 +50,16 @@ def build_urls(fields):
     """Build personalized URLs using the developer information in
     fields."""
     data = []
-    qfields = dict([(key, quote_plus(fields[key].encode('utf8'))) \
-                        for key in fields \
-                        if fields[key] is not None and isinstance(fields[key], unicode)])
+    qfields = {}
+    for key, value in fields.iteritems():
+        if value is not None:
+            if isinstance(value, unicode):
+                qfields[key] = quote_plus(value.encode('utf8'))
+            elif isinstance(value, str):
+                qfields[key] = quote_plus(value)
+            else:
+                qfields[key] = value
+
     if 'gpgfp' not in qfields:
         fpr = keyfinder.getFingerprintByEmail(fields['email'].encode('utf8'))
         if fpr: