diff --git a/librefi/utils.py b/librefi/utils.py
index c1234ea..2e1c043 100644
--- a/librefi/utils.py
+++ b/librefi/utils.py
@@ -1,7 +1,7 @@
 # flake8: noqa: E501
 
 import re
-from urllib.parse import parse_qs, quote
+from urllib.parse import parse_qs, quote as qs_quote
 
 
 def get_user_agent():
@@ -20,11 +20,33 @@ def regex_search_string(regexes, string, default=None):
 
 
 def dump_qs(obj):
-    qs = ""
+    old_qs = []
+    qs = []
     for key in obj:
-        if isinstance(obj[key], (str, int, float)):
-            qs += quote(key) + "=" + quote(str(obj[key]))
-        else:
-            # TODO: support nested dicts and lists
-            raise TypeError("unknown types in dump_qs")
-    return qs
+        old_qs.append((key, obj[key]))
+    not_flat = True
+    while not_flat:
+        not_flat = False
+        for old_qs_element in old_qs:
+            if isinstance(old_qs_element[1], (str, int, float)):
+                qs.append((old_qs_element[0], old_qs_element[1]))
+            elif isinstance(old_qs_element[1], (dict)):
+                for subkey in old_qs_element[1]:
+                    qs.append(
+                        (old_qs_element[0] + "[" + subkey + "]", old_qs_element[1][subkey]))
+                    if isinstance(old_qs_element[1][subkey], (dict, list)):
+                        not_flat = True
+            elif isinstance(old_qs_element[1], (list)):
+                for element in old_qs_element[1]:
+                    qs.append(
+                        (old_qs_element[0] + "[]", element))
+                    if isinstance(element, (dict, list)):
+                        not_flat = True
+        if not_flat:
+            old_qs = qs
+            qs = []
+    strng = ""
+    for el in qs:
+        strng += qs_quote(str(el[0]), encoding="utf8") + "=" + \
+            qs_quote(str(el[1]), encoding="utf8") + "&"
+    return strng[:-1]