diff --git a/src/PostgREST/Auth.hs b/src/PostgREST/Auth.hs
index 5c1f029da..d14c50ff4 100644
--- a/src/PostgREST/Auth.hs
+++ b/src/PostgREST/Auth.hs
@@ -20,9 +20,10 @@ module PostgREST.Auth
 
 import qualified Crypto.JWT                      as JWT
 import qualified Data.Aeson                      as JSON
+import qualified Data.Aeson.Key                  as K
+import qualified Data.Aeson.KeyMap               as KM
 import qualified Data.Aeson.Types                as JSON
 import qualified Data.ByteString.Lazy.Char8      as LBS
-import qualified Data.HashMap.Strict             as HM
 import qualified Data.Text.Encoding              as T
 import qualified Data.Vault.Lazy                 as Vault
 import qualified Data.Vector                     as V
@@ -45,7 +46,7 @@ import Protolude
 
 
 data AuthResult = AuthResult
-  { authClaims :: HM.HashMap Text JSON.Value
+  { authClaims :: KM.KeyMap JSON.Value
   , authRole   :: Text
   }
 
@@ -78,13 +79,13 @@ parseClaims AppConfig{..} jclaims@(JSON.Object mclaims) = do
   role <- liftEither . maybeToRight JwtTokenRequired $
     unquoted <$> walkJSPath (Just jclaims) configJwtRoleClaimKey <|> configDbAnonRole
   return AuthResult
-           { authClaims = mclaims & HM.insert "role" (JSON.toJSON role)
+           { authClaims = mclaims & KM.insert "role" (JSON.toJSON role)
            , authRole = role
            }
   where
     walkJSPath :: Maybe JSON.Value -> JSPath -> Maybe JSON.Value
     walkJSPath x                      []                = x
-    walkJSPath (Just (JSON.Object o)) (JSPKey key:rest) = walkJSPath (HM.lookup key o) rest
+    walkJSPath (Just (JSON.Object o)) (JSPKey key:rest) = walkJSPath (KM.lookup (K.fromText key) o) rest
     walkJSPath (Just (JSON.Array ar)) (JSPIdx idx:rest) = walkJSPath (ar V.!? idx) rest
     walkJSPath _                      _                 = Nothing
 
@@ -92,7 +93,7 @@ parseClaims AppConfig{..} jclaims@(JSON.Object mclaims) = do
     unquoted (JSON.String t) = t
     unquoted v = T.decodeUtf8 . LBS.toStrict $ JSON.encode v
 -- impossible case - just added to please -Wincomplete-patterns
-parseClaims _ _ = return AuthResult { authClaims = HM.empty, authRole = mempty }
+parseClaims _ _ = return AuthResult { authClaims = KM.empty, authRole = mempty }
 
 -- | Validate authorization header.
 --   Parse and store JWT claims for future use in the request.
diff --git a/src/PostgREST/GucHeader.hs b/src/PostgREST/GucHeader.hs
index 5b8b5ebd5..2deba6999 100644
--- a/src/PostgREST/GucHeader.hs
+++ b/src/PostgREST/GucHeader.hs
@@ -5,8 +5,9 @@ module PostgREST.GucHeader
   ) where
 
 import qualified Data.Aeson           as JSON
+import qualified Data.Aeson.Key       as K
+import qualified Data.Aeson.KeyMap    as KM
 import qualified Data.CaseInsensitive as CI
-import qualified Data.HashMap.Strict  as HM
 
 import Network.HTTP.Types.Header (Header)
 
@@ -21,8 +22,8 @@ newtype GucHeader = GucHeader (CI.CI ByteString, ByteString)
 
 instance JSON.FromJSON GucHeader where
   parseJSON (JSON.Object o) =
-    case HM.toList o of
-      [(k, JSON.String s)] -> pure $ GucHeader (CI.mk $ toUtf8 k, toUtf8 s)
+    case KM.toList o of
+      [(k, JSON.String s)] -> pure $ GucHeader (CI.mk $ toUtf8 $ K.toText k, toUtf8 s)
       _ -> mzero
   parseJSON _ = mzero
 
diff --git a/src/PostgREST/Middleware.hs b/src/PostgREST/Middleware.hs
index 359bd1180..507202d22 100644
--- a/src/PostgREST/Middleware.hs
+++ b/src/PostgREST/Middleware.hs
@@ -10,6 +10,8 @@ module PostgREST.Middleware
   ) where
 
 import qualified Data.Aeson                        as JSON
+import qualified Data.Aeson.Key                    as K
+import qualified Data.Aeson.KeyMap                 as KM
 import qualified Data.ByteString.Lazy.Char8        as LBS
 import qualified Data.HashMap.Strict               as HM
 import qualified Data.Text                         as T
@@ -38,7 +40,7 @@ import PostgREST.Request.Preferences
 import Protolude
 
 -- | Runs local(transaction scoped) GUCs for every request, plus the pre-request function
-runPgLocals :: AppConfig   -> HM.HashMap Text JSON.Value -> Text ->
+runPgLocals :: AppConfig   -> KM.KeyMap JSON.Value -> Text ->
                (ApiRequest -> ExceptT Error SQL.Transaction Wai.Response) ->
                ApiRequest  -> ByteString -> PgVersion -> ExceptT Error SQL.Transaction Wai.Response
 runPgLocals conf claims role app req jsonDbS actualPgVersion = do
@@ -57,7 +59,7 @@ runPgLocals conf claims role app req jsonDbS actualPgVersion = do
                    then setConfigLocal "request.cookie." <$> iCookies req
                    else setConfigLocalJson "request.cookies" (iCookies req)
     claimsSql = if usesLegacyGucs
-                  then setConfigLocal "request.jwt.claim." <$> [(toUtf8 c, toUtf8 $ unquoted v) | (c,v) <- HM.toList claims]
+                  then setConfigLocal "request.jwt.claim." <$> [(toUtf8 $ K.toText c, toUtf8 $ unquoted v) | (c,v) <- KM.toList claims]
                   else [setConfigLocal mempty ("request.jwt.claims", LBS.toStrict $ JSON.encode claims)]
     roleSql = [setConfigLocal mempty ("role", toUtf8 role)]
     appSettingsSql = setConfigLocal mempty <$> (join bimap toUtf8 <$> configAppSettings conf)
diff --git a/src/PostgREST/Request/ApiRequest.hs b/src/PostgREST/Request/ApiRequest.hs
index 2cd2f309a..8dc4c5d89 100644
--- a/src/PostgREST/Request/ApiRequest.hs
+++ b/src/PostgREST/Request/ApiRequest.hs
@@ -18,6 +18,8 @@ module PostgREST.Request.ApiRequest
   ) where
 
 import qualified Data.Aeson            as JSON
+import qualified Data.Aeson.Key        as K
+import qualified Data.Aeson.KeyMap     as KM
 import qualified Data.ByteString.Char8 as BS
 import qualified Data.ByteString.Lazy  as LBS
 import qualified Data.CaseInsensitive  as CI
@@ -25,6 +27,7 @@ import qualified Data.Csv              as CSV
 import qualified Data.HashMap.Strict   as HM
 import qualified Data.List             as L
 import qualified Data.List.NonEmpty    as NonEmptyList
+import qualified Data.Map.Strict       as M
 import qualified Data.Set              as S
 import qualified Data.Text.Encoding    as T
 import qualified Data.Vector           as V
@@ -357,7 +360,7 @@ mutuallyAgreeable sProduces cAccepts =
      then listToMaybe sProduces
      else exact
 
-type CsvData = V.Vector (HM.HashMap Text LBS.ByteString)
+type CsvData = V.Vector (M.Map Text LBS.ByteString)
 
 {-|
   Converts CSV like
@@ -375,8 +378,8 @@ csvToJson :: (CSV.Header, CsvData) -> JSON.Value
 csvToJson (_, vals) =
   JSON.Array $ V.map rowToJsonObj vals
  where
-  rowToJsonObj = JSON.Object .
-    HM.map (\str ->
+  rowToJsonObj = JSON.Object . KM.fromMapText .
+    M.map (\str ->
         if str == "NULL"
           then JSON.Null
           else JSON.String . T.decodeUtf8 $ LBS.toStrict str
@@ -389,9 +392,9 @@ payloadAttributes raw json =
     JSON.Array arr ->
       case arr V.!? 0 of
         Just (JSON.Object o) ->
-          let canonicalKeys = S.fromList $ HM.keys o
+          let canonicalKeys = S.fromList $ K.toText <$> KM.keys o
               areKeysUniform = all (\case
-                JSON.Object x -> S.fromList (HM.keys x) == canonicalKeys
+                JSON.Object x -> S.fromList (K.toText <$> KM.keys x) == canonicalKeys
                 _ -> False) arr in
           if areKeysUniform
             then Just $ ProcessedJSON raw canonicalKeys
@@ -399,7 +402,7 @@ payloadAttributes raw json =
         Just _ -> Nothing
         Nothing -> Just emptyPJArray
 
-    JSON.Object o -> Just $ ProcessedJSON raw (S.fromList $ HM.keys o)
+    JSON.Object o -> Just $ ProcessedJSON raw (S.fromList $ K.toText <$> KM.keys o)
 
     -- truncate everything else to an empty array.
     _ -> Just emptyPJArray