diff --git a/requirements.txt b/requirements.txt
index 5ce17b531461a9ef9bfb805f27a842517643156a..973c4bd23ac031b8044a321beee265f8e0b4b122 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -50,6 +50,7 @@ requests==2.22.0
 scipy==1.4.1
 seaborn==0.10.0
 setproctitle==1.1.10
+simplejson==3.17.5
 six==1.13.0
 snowballstemmer==2.0.0
 Sphinx==2.2.1
diff --git a/setup.py b/setup.py
index 820ff8a4c22b97f519552bc7e67fa5c4d300a1ad..a99a68f126546d4fa1d36442ececcc061a49d7d8 100644
--- a/setup.py
+++ b/setup.py
@@ -249,22 +249,23 @@ setup(
         "binarycpython.tests",
     ],
     install_requires=[
-        "numpy",
-        "pytest",
-        "h5py",
-        "pathos",
-        "pandas",
         "astropy",
+        "colorama",
+        "h5py",
+        "halo",
+        "humanize",
         "matplotlib",
-        "seaborn",
+        "msgpack",
+        "numpy",
+        "pandas",
+        "pathos",
+        "psutil",
+        "pytest",
         "py_rinterpolate",
+        "seaborn",
         "setproctitle",
-        "psutil",
-        "colorama",
+        "simplejson"
         "strip-ansi",
-        "humanize",
-        "halo",
-        "msgpack"
     ],
     include_package_data=True,
     ext_modules=[BINARY_C_PYTHON_API_MODULE],  # binary_c must be loaded