diff --git a/mathics_pygments/builtins.py b/mathics_pygments/builtins.py
index 09af80b..099b847 100644
--- a/mathics_pygments/builtins.py
+++ b/mathics_pygments/builtins.py
@@ -4,7 +4,10 @@
 # Licensed under the MIT License (https://opensource.org/licenses/MIT)
 
 import os.path as osp
-import ujson
+try:
+    import ujson
+except ImportError:
+    import json as ujson
 
 def get_datadir():
     datadir = osp.normcase(osp.join(osp.dirname(osp.abspath(__file__)), "data"))
diff --git a/requirements-dev.txt b/requirements-dev.txt
index e079f8a..77b540c 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1 +1,3 @@
+# ujson is really just optional
+ujson
 pytest
diff --git a/setup.py b/setup.py
index 3ed2239..afff34c 100644
--- a/setup.py
+++ b/setup.py
@@ -83,7 +83,7 @@ def read(*rnames):
             "data/mma-tables.json",
         ],
     },
-    install_requires=["Pygments >= 2", "Mathics_Scanner>=1.2.0", "ujson"],
+    install_requires=["Pygments >= 2", "Mathics_Scanner>=1.2.0"],
     include_package_data=False,
     platforms=["any"],
     entry_points={