diff --git a/lib/spack/spack/util/spack_json.py b/lib/spack/spack/util/spack_json.py
index 232852fd229..579d0469851 100644
--- a/lib/spack/spack/util/spack_json.py
+++ b/lib/spack/spack/util/spack_json.py
@@ -11,7 +11,7 @@
 
 __all__ = ["load", "dump", "SpackJSONError"]
 
-_json_dump_args = {"indent": 2, "separators": (",", ": ")}
+_json_dump_args = {"indent": None, "separators": (",", ":")}
 
 
 def load(stream: Any) -> Dict: