diff --git a/aeson-value-parser.cabal b/aeson-value-parser.cabal
--- a/aeson-value-parser.cabal
+++ b/aeson-value-parser.cabal
@@ -1,5 +1,5 @@
 name: aeson-value-parser
-version: 0.16
+version: 0.17
 synopsis: API for parsing "aeson" JSON tree into Haskell types
 description:
   A flexible parser DSL of JSON AST produced by the \"aeson\" library
@@ -37,6 +37,7 @@
     attoparsec >=0.13 && <0.14,
     base >=4.9 && <5,
     bytestring >=0.10 && <0.12,
+    hashable >=1.3 && <2,
     mtl >=2.2 && <3,
     scientific ==0.3.*,
     text ==1.*,
diff --git a/library/Aeson/ValueParser.hs b/library/Aeson/ValueParser.hs
--- a/library/Aeson/ValueParser.hs
+++ b/library/Aeson/ValueParser.hs
@@ -1,7 +1,7 @@
 {-
 Parser DSL for the \"aeson\" model of JSON tree.
 
-The general model of this DSL is about switching between contexts
+The general model of this DSL is about switching between contexts.
 -}
 module Aeson.ValueParser
 (
@@ -92,6 +92,9 @@
     Aeson.Bool _ -> "Unexpected type: bool"
     Aeson.Null -> "Unexpected type: null"
 
+runString :: String a -> Text -> Either (Maybe Text) a
+runString (String a) b = runExcept (runReaderT a b)
+
 -- ** Definitions
 -------------------------
 
@@ -238,11 +241,14 @@
 oneOfFields keys valueParser = asum (fmap (flip field valueParser) keys)
 
 {-# INLINE fieldMap #-}
-fieldMap :: Value a -> Object (HashMap Text a)
-fieldMap fieldParser = Object $ ReaderT $ HashMap.traverseWithKey mapping where
-  mapping key ast = case run fieldParser ast of
-    Right parsedField -> return parsedField
-    Left error -> lift (throwE (Error.named key error))
+fieldMap :: (Eq a, Hashable a) => String a -> Value b -> Object (HashMap a b)
+fieldMap keyParser fieldParser = Object $ ReaderT $ fmap HashMap.fromList . traverse mapping . HashMap.toList where
+  mapping (keyText, ast) = 
+    case runString keyParser keyText of
+      Right parsedKey -> case run fieldParser ast of
+        Right parsedField -> return (parsedKey, parsedField)
+        Left error -> lift (throwE (Error.named keyText error))
+      Left error -> lift (throwE (maybe mempty Error.message error))
 
 {-# INLINE foldlFields #-}
 foldlFields :: (state -> Text -> field -> state) -> state -> Value field -> Object state
diff --git a/library/Aeson/ValueParser/Prelude.hs b/library/Aeson/ValueParser/Prelude.hs
--- a/library/Aeson/ValueParser/Prelude.hs
+++ b/library/Aeson/ValueParser/Prelude.hs
@@ -105,6 +105,10 @@
 -------------------------
 import Data.Scientific as Exports (Scientific)
 
+-- hashable
+-------------------------
+import Data.Hashable as Exports (Hashable)
+
 
 showText :: Show a => a -> Text
 showText = fromString . show