diff --git a/IHP/ModelSupport.hs b/IHP/ModelSupport.hs
index 9ded7cbd6..d889e3f26 100644
--- a/IHP/ModelSupport.hs
+++ b/IHP/ModelSupport.hs
@@ -129,6 +129,9 @@ instance InputValue fieldType => InputValue (Maybe fieldType) where
 instance InputValue value => InputValue [value] where
     inputValue list = list |> map inputValue |> intercalate ","
 
+instance InputValue Aeson.Value where
+    inputValue json = json |> Aeson.encode |> cs
+
 instance Default Text where
     {-# INLINE def #-}
     def = ""
diff --git a/Test/Main.hs b/Test/Main.hs
index 04b30a0da..2a63e78d6 100644
--- a/Test/Main.hs
+++ b/Test/Main.hs
@@ -31,6 +31,7 @@ import qualified Test.View.CSSFrameworkSpec
 import qualified Test.Controller.ContextSpec
 import qualified Test.Controller.ParamSpec
 import qualified Test.SchemaMigrationSpec
+import qualified Test.ModelSupportSpec
 
 main :: IO ()
 main = hspec do
@@ -48,4 +49,5 @@ main = hspec do
     Test.View.CSSFrameworkSpec.tests
     Test.Controller.ContextSpec.tests
     Test.Controller.ParamSpec.tests
-    Test.SchemaMigrationSpec.tests
\ No newline at end of file
+    Test.SchemaMigrationSpec.tests
+    Test.ModelSupportSpec.tests
\ No newline at end of file
diff --git a/Test/ModelSupportSpec.hs b/Test/ModelSupportSpec.hs
new file mode 100644
index 000000000..5acd0cf21
--- /dev/null
+++ b/Test/ModelSupportSpec.hs
@@ -0,0 +1,79 @@
+{-|
+Module: Test.HaskellSupportSpec
+Copyright: (c) digitally induced GmbH, 2020
+-}
+module Test.ModelSupportSpec where
+
+import Test.Hspec
+import IHP.Prelude
+import IHP.ModelSupport
+import qualified Data.Aeson as Aeson
+
+tests = do
+    describe "ModelSupport" do
+        describe "InputValue" do
+            describe "Text" do
+                it "should return the text" do
+                    let text :: Text = "Lorem Ipsum"
+                    (inputValue text) `shouldBe` text
+            
+            describe "Int" do
+                it "should return numeric representation" do
+                    (inputValue (1 :: Int)) `shouldBe` "1"
+            
+            describe "Integer" do
+                it "should return numeric representation" do
+                    (inputValue (1 :: Int)) `shouldBe` "1"
+            
+            describe "Double" do
+                it "should return numeric representation" do
+                    (inputValue (1.337 :: Double)) `shouldBe` "1.337"
+            
+            describe "Float" do
+                it "should return numeric representation" do
+                    (inputValue (1.337 :: Float)) `shouldBe` "1.337"
+            
+            describe "Bool" do
+                it "should deal with True and False" do
+                    (inputValue True) `shouldBe` "on"
+                    (inputValue False) `shouldBe` "off"
+            
+            describe "UUID" do
+                it "should return text representation" do
+                    let uuid :: UUID = "b9a1129e-e53a-4370-b778-0d1c28dc6ecc"
+                    (inputValue uuid) `shouldBe` "b9a1129e-e53a-4370-b778-0d1c28dc6ecc"
+            
+            describe "UTCTime" do
+                it "should return text representation" do
+                    let (Just utctime) :: Maybe UTCTime = parseTimeM True defaultTimeLocale "%Y-%m-%dT%H:%M:%S%QZ" "2020-11-08T12:03:35Z"
+                    (inputValue utctime) `shouldBe` "2020-11-08T12:03:35Z"
+            
+            describe "Day" do
+                it "should return text representation" do
+                    let (Just utctime) :: Maybe UTCTime = parseTimeM True defaultTimeLocale "%Y-%m-%dT%H:%M:%S%QZ" "2020-11-08T12:03:35Z"
+                    let day :: Day = utctDay utctime
+                    (inputValue day) `shouldBe` "2020-11-08"
+            
+            describe "Maybe" do
+                it "should return empty string on Nothing" do
+                    let value :: Maybe Int = Nothing
+                    (inputValue value) `shouldBe` ""
+                
+                it "should return the value if Just" do
+                    let value :: Maybe Int = Just 1
+                    (inputValue value) `shouldBe` "1"
+            
+            describe "[a]" do
+                it "should return CSV" do
+                    let value :: [Int] = [1, 2, 3]
+                    (inputValue value) `shouldBe` "1,2,3"
+                
+                it "should return empty string on empty list" do
+                    let value :: [Int] = []
+                    (inputValue value) `shouldBe` ""
+            
+            describe "JSON" do
+                it "should return a json string for a Aeson.Value" do
+                    let (Just value) :: Maybe Aeson.Value = Aeson.decode "{\"hello\":true}"
+                    (inputValue value) `shouldBe` "{\"hello\":true}"
+