diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Revision history for stooq
 
+## 0.4.0.0 -- 2022-11-27
+
+* Switching to XML format, which seems more reliable than JSON.
+
 ## 0.3.1.0 -- 2022-07-07
 
 * Migrating to nixpkgs 22.05.
diff --git a/src/lib/Web/Data/Stooq/API.hs b/src/lib/Web/Data/Stooq/API.hs
--- a/src/lib/Web/Data/Stooq/API.hs
+++ b/src/lib/Web/Data/Stooq/API.hs
@@ -49,9 +49,10 @@
 
 -- | Sends a request for the specified ticker and returns its latest price.
 -- Returns "Nothing" if the response is invalid (this is most likely due to using a non-existent ticker).
-fetchPrice :: StooqSymbol -> IO (Maybe [StooqPrice])
+fetchPrice :: StooqSymbol -> IO (Either String [StooqPrice])
 fetchPrice ticker = do
-    r <- get (queryUrl ticker)
+    let url = queryUrl ticker
+    r <- get url
     return $ fmap (map toApiType . Impl.symbols) (Impl.parseResponse (r ^. responseBody))
 
     where
@@ -59,7 +60,7 @@
         baseUrl = "https://stooq.pl/q/l/?s="
 
         queryUrl :: StooqSymbol -> String
-        queryUrl (StooqSymbol ticker) = baseUrl ++ ticker ++ "&e=json"
+        queryUrl (StooqSymbol ticker) = baseUrl ++ ticker ++ "&e=xml"
 
         toApiType :: Impl.StooqRow -> StooqPrice
         toApiType row = StooqPrice {
@@ -84,12 +85,12 @@
 
 -- | Sends a request for multiple tickers at once.
 -- The function makes only a single HTTP call.
-fetchPrices :: [StooqSymbol] -> IO (Maybe [StooqPrice])
+fetchPrices :: [StooqSymbol] -> IO (Either String [StooqPrice])
 fetchPrices tickers = fetchPrice (concatTickers tickers)
     where
         concatTickers :: [StooqSymbol] -> StooqSymbol
         concatTickers = foldl1 (\(StooqSymbol t1) (StooqSymbol t2) -> StooqSymbol (t1 ++ " " ++ t2))
 
 -- | A shorthand around "fetchPrice" that allows to call the function using a plain String, without converting it to a `StooqSymbol` first.
-fetch :: String -> IO (Maybe [StooqPrice])
+fetch :: String -> IO (Either String [StooqPrice])
 fetch = fetchPrice . StooqSymbol
diff --git a/src/utils/Web/Data/Stooq/Internals.hs b/src/utils/Web/Data/Stooq/Internals.hs
--- a/src/utils/Web/Data/Stooq/Internals.hs
+++ b/src/utils/Web/Data/Stooq/Internals.hs
@@ -1,14 +1,16 @@
 {-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE FlexibleInstances #-}
 
 module Web.Data.Stooq.Internals where
 
-import Data.Aeson (FromJSON, decode)
-import Data.ByteString.Lazy (ByteString, empty)
-import Data.ByteString.Char8 (pack)
-import Data.ByteString.Lazy.Search (replace)
+import Data.ByteString.Lazy (ByteString)
+import Data.Maybe (fromMaybe, catMaybes)
 import Data.Text (Text)
 import GHC.Generics (Generic)
 
+import Data.Csv (decode, HasHeader(NoHeader), FromField, parseField, runParser)
+import qualified Data.Vector as V
+
 data StooqRow =
     StooqRow {
         symbol  :: !Text,
@@ -21,16 +23,38 @@
         volume  :: Int
     } deriving (Show, Generic)
 
-data StooqResponse =
+newtype StooqResponse =
     StooqResponse {
         symbols :: [StooqRow]
     } deriving (Show, Generic)
 
-instance FromJSON StooqRow
-instance FromJSON StooqResponse
+data TryField a = FieldValue a | NoValue
 
-parseResponse :: ByteString -> Maybe StooqResponse
-parseResponse = decode . replace searchedSubstring replacement
+instance FromField (TryField Text) where
+    parseField s = case runParser (parseField s) of
+        Left err -> pure NoValue
+        Right v  -> pure $ FieldValue v
+
+instance FromField (TryField Double) where
+    parseField s = case runParser (parseField s) of
+        Left err -> pure NoValue
+        Right v  -> pure $ FieldValue v
+
+instance FromField (TryField Int) where
+    parseField s = case runParser (parseField s) of
+        Left err -> pure NoValue
+        Right v  -> pure $ FieldValue v
+
+parseResponse :: ByteString -> Either String StooqResponse
+parseResponse input =
+    fmap (StooqResponse . catMaybes . V.toList . V.map tupleToStooqRow) (decode NoHeader input)
+
     where
-        searchedSubstring = pack ",\"openint\":}"
-        replacement = pack "}"
+        tupleToStooqRow :: (Text, TryField Int, TryField Text, TryField Double, TryField Double, TryField Double, TryField Double, TryField Int, Text) -> Maybe StooqRow
+        tupleToStooqRow (name, FieldValue date, FieldValue time, FieldValue open, FieldValue high, FieldValue low, FieldValue close, volume, _) =
+            Just $ StooqRow name date time open high low close (defaultToZero volume)
+        tupleToStooqRow (name, _, _, _, _, _, _, _, _) = Nothing
+
+        defaultToZero :: TryField Int -> Int
+        defaultToZero (FieldValue x) = x
+        defaultToZero NoValue = 0
diff --git a/stooq-api.cabal b/stooq-api.cabal
--- a/stooq-api.cabal
+++ b/stooq-api.cabal
@@ -1,7 +1,7 @@
 cabal-version:      2.0
 
 name:               stooq-api
-version:            0.3.1.0
+version:            0.4.1.0
 synopsis:           A simple wrapper around stooq.pl API for downloading market data.
 description:
   Here's a simple wrapper around API offered by Stooq.pl.
@@ -24,11 +24,11 @@
 library stooq-api-utils
   exposed-modules:    Web.Data.Stooq.Internals
   build-depends:      base,
-                      aeson,
                       bytestring,
-                      stringsearch,
+                      cassava,
                       text,
-                      time
+                      time,
+                      vector
   hs-source-dirs:     src/utils
   default-language:   Haskell2010
 
@@ -36,14 +36,13 @@
     exposed-modules:  Web.Data.Stooq.API
     build-depends:    base          >= 4.13     && < 4.16,
                       bytestring    >= 0.10.10  && < 0.11,
-                      aeson         >= 2.0      && < 2.1,
+                      cassava       >= 0.5.2    && < 0.5.3,
                       lens          >= 4.18.1   && < 5.1,
                       text          >= 1.2      && < 1.3,
                       time          >= 1.9.3    && < 1.10,
                       utf8-string   >= 1.0.2    && < 1.1,
                       vector        >= 0.12.1   && < 0.13,
                       wreq          >= 0.5.3    && < 0.6,
-                      stringsearch  >= 0.3      && < 0.4,
                       stooq-api-utils
     hs-source-dirs:   src/lib
     default-language: Haskell2010