diff --git a/app/Main.hs b/app/Main.hs
index 4509d5726..3ddfdee23 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -13,6 +13,7 @@ arguments :: Parser Arguments
 arguments = Arguments
   <$> (flag DO.Split DO.Unified (long "unified" <> help "output a unified diff")
   <|> flag DO.Split DO.Patch (long "patch" <> help "output a patch(1)-compatible diff")
+  <|> flag DO.Split DO.JSON (long "json" <> help "output a json diff")
   <|> flag' DO.Split (long "split" <> help "output a split diff"))
   <*> optional (strOption (long "output" <> short 'o' <> help "output directory for split diffs, defaulting to stdout if unspecified"))
   <*> strArgument (metavar "FILE a")