diff --git a/koodihaaste.cabal b/koodihaaste.cabal
index cf54248..67383e9 100644
--- a/koodihaaste.cabal
+++ b/koodihaaste.cabal
@@ -18,6 +18,7 @@ build-type:          Simple
 extra-source-files:  CHANGELOG.md
 
 executable koodihaaste
+  ghc-options:         -threaded -O2 -rtsopts
   main-is:             Main.hs
   other-modules:       Data.Language
                      , Data.NGram
@@ -45,5 +46,6 @@ executable koodihaaste
                      , lucid
                      , warp
                      , yaml
+                     , parallel
   hs-source-dirs:      src
   default-language:    Haskell2010
diff --git a/src/API.hs b/src/API.hs
index 7008ae5..830e83b 100644
--- a/src/API.hs
+++ b/src/API.hs
@@ -32,6 +32,7 @@ import           Servant.API
 import           Servant.API.Generic
 import           Servant.HTML.Lucid
 import           Servant.Server.Generic
+import Control.Parallel.Strategies
 
 import           Data.Caesar
 import           Data.Language
@@ -78,7 +79,8 @@ handler =
     _index = do
       languageModel <- asks getModel
       sentences <- map message . bullshits <$> getBullshits
-      let (bullshit, noBullshit) = partitionEithers (map (findBest languageModel) sentences)
+      let (bullshit, noBullshit) = partitionEithers best
+          best = map (findBest languageModel) sentences `using` parBuffer 10 rdeepseq
       return $ Index noBullshit bullshit
   }
   where