diff --git a/Network/Wai/Middleware/Gzip.hs b/Network/Wai/Middleware/Gzip.hs
--- a/Network/Wai/Middleware/Gzip.hs
+++ b/Network/Wai/Middleware/Gzip.hs
@@ -19,6 +19,7 @@
     , GzipSettings
     , gzipFiles
     , GzipFiles (..)
+    , gzipCheckMime
     , def
     , defaultCheckMime
     ) where
@@ -51,7 +52,7 @@
     def = GzipSettings GzipIgnore defaultCheckMime
 
 defaultCheckMime :: S.ByteString -> Bool
-defaultCheckMime = S8.isPrefixOf "text/"
+defaultCheckMime bs = S8.isPrefixOf "text/" bs || S8.isPrefixOf "application/json" bs
 
 -- | Use gzip to compress the body of the response.
 --
diff --git a/wai-extra.cabal b/wai-extra.cabal
--- a/wai-extra.cabal
+++ b/wai-extra.cabal
@@ -1,5 +1,5 @@
 Name:                wai-extra
-Version:             1.3.2.4
+Version:             1.3.3
 Synopsis:            Provides some basic WAI handlers and middleware.
 Description:         The goal here is to provide common features without many dependencies.
 License:             MIT