diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+### 1.13.1
+
+* Add `Applicative` and `Monad` instances for `Reason`.
+* Add `Eq`, `Ord` and `Read` instances for `Void`.
+
 ## 1.13
 
 * Change the type of `Reason_` from `Reason ()` to `Reason Void`
diff --git a/rest-types.cabal b/rest-types.cabal
--- a/rest-types.cabal
+++ b/rest-types.cabal
@@ -1,5 +1,5 @@
 name:                rest-types
-version:             1.13
+version:             1.13.1
 description:         Silk Rest Framework Types
 synopsis:            Silk Rest Framework Types
 maintainer:          code@silk.co
diff --git a/src/Rest/Types/Error.hs b/src/Rest/Types/Error.hs
--- a/src/Rest/Types/Error.hs
+++ b/src/Rest/Types/Error.hs
@@ -23,6 +23,8 @@
   , ToResponseCode (..)
   ) where
 
+import Control.Applicative (Applicative (..))
+import Control.Monad (ap)
 import Data.Aeson hiding (Success)
 import Data.Foldable (Foldable)
 import Data.JSON.Schema (JSONSchema (..), gSchema)
@@ -109,6 +111,28 @@
   -- Custom domain reasons.
   | CustomReason (DomainReason a)
   deriving (Eq, Generic, Show, Typeable, Functor, Foldable, Traversable)
+
+instance Applicative Reason where
+  pure = return
+  (<*>) = ap
+
+instance Monad Reason where
+  return a = CustomReason (DomainReason a)
+  r >>= f = case r of
+    CustomReason (DomainReason a) -> f a
+    UnsupportedRoute              -> UnsupportedRoute
+    UnsupportedMethod             -> UnsupportedMethod
+    UnsupportedVersion            -> UnsupportedVersion
+    IdentError   e                -> IdentError   e
+    HeaderError  e                -> HeaderError  e
+    ParamError   e                -> ParamError   e
+    InputError   e                -> InputError   e
+    OutputError  e                -> OutputError  e
+    NotFound                      -> NotFound
+    NotAllowed                    -> NotAllowed
+    AuthenticationFailed          -> AuthenticationFailed
+    Busy                          -> Busy
+    Gone                          -> Gone
 
 deriveAll ''DataError "PFDataError"
 deriveAll ''Reason    "PFReason"
diff --git a/src/Rest/Types/Void.hs b/src/Rest/Types/Void.hs
--- a/src/Rest/Types/Void.hs
+++ b/src/Rest/Types/Void.hs
@@ -38,6 +38,15 @@
 instance Show Void where
   show = magic
 
+instance Eq Void where
+  x == _ = magic x
+
+instance Ord Void where
+  compare x _ = magic x
+
+instance Read Void where
+  readsPrec _ _ = []
+
 -- | Generic. Can't derive it, sadly.
 
 instance Generic Void where