diff --git a/requirements.txt b/requirements.txt
index 8c1766b..a7ca0c4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -18,3 +18,4 @@ sncosmo>=2.1.0
 pytest-randomly>=2.1.1
 pytest>=4.3.1
 astroquery>=0.3
+simplejson