diff --git a/src/pyff/api.py b/src/pyff/api.py
index eb49e805..db1c5fb3 100644
--- a/src/pyff/api.py
+++ b/src/pyff/api.py
@@ -4,7 +4,7 @@
 from datetime import datetime, timedelta
 from json import dumps
 from typing import Any, Optional
-from urllib.parse import quote_plus
+from urllib.parse import quote
 
 import pyramid.httpexceptions as exc
 import pytz
@@ -394,7 +394,7 @@ def _links(url: str, title: Any = None) -> None:
     aliases = request.registry.aliases
     for a in aliases.keys():
         for v in request.registry.md.store.attribute(aliases[a]):
-            _links(f'{a}/{quote_plus(v)}')
+            _links(f'{a}/{quote(v)}')
 
     response = Response(dumps(jrd, default=json_serializer))
     response.headers['Content-Type'] = 'application/json'
diff --git a/src/pyff/builtins.py b/src/pyff/builtins.py
index 9c560956..3b52fc86 100644
--- a/src/pyff/builtins.py
+++ b/src/pyff/builtins.py
@@ -15,7 +15,7 @@
 from datetime import datetime
 from io import BytesIO
 from typing import Optional
-from urllib.parse import quote_plus, urlparse
+from urllib.parse import quote, urlparse
 
 import xmlsec
 from lxml import etree
@@ -539,7 +539,7 @@ def _nop(x):
 
     enc = _nop
     if req.args.get('urlencode_filenames'):
-        enc = quote_plus
+        enc = quote
 
     if output_file is None:
         return req.t