diff --git a/src/PaymentServer/Main.hs b/src/PaymentServer/Main.hs
index f439a4e419be143af28d974888005d9feeeddea8..941d4c245cc13a5b6f9a76aaaccf75cf2a405122 100644
--- a/src/PaymentServer/Main.hs
+++ b/src/PaymentServer/Main.hs
@@ -204,7 +204,7 @@ logEndpoint endpoint =
 getApp :: ServerConfig -> IO Application
 getApp config =
   let
-    getIssuer ServerConfig{ issuer, signingKeyPath } = do
+    getIssuer ServerConfig{ issuer, signingKeyPath } =
       case (issuer, signingKeyPath) of
         (Trivial, Nothing) -> return $ Right trivialIssue
         (Ristretto, Just keyPath) -> do
diff --git a/src/PaymentServer/Processors/Stripe.hs b/src/PaymentServer/Processors/Stripe.hs
index 36cc53519cdda3ad4b1b08717efedad7a1f66811..8caef6e85bda6313da43e98ab577e2a63fc73a10 100644
--- a/src/PaymentServer/Processors/Stripe.hs
+++ b/src/PaymentServer/Processors/Stripe.hs
@@ -174,7 +174,7 @@ charge d key (Charges token voucher amount currency) = do
     Left StripeError {} -> throwError err400 { errBody = "Stripe charge didn't succeed" }
     where
       getCurrency :: Text -> Handler Currency
-      getCurrency maybeCurrency = do
+      getCurrency maybeCurrency =
         case readMaybe (unpack currency) of
           Just currency' -> return currency'
           Nothing -> throwError err400 { errBody = "Invalid currency specified" }
diff --git a/src/PaymentServer/Server.hs b/src/PaymentServer/Server.hs
index 1dd455723151a5b922edd42c286721e469f9ae27..feef0b051330a58568fa88ded64667b74719049a 100644
--- a/src/PaymentServer/Server.hs
+++ b/src/PaymentServer/Server.hs
@@ -1,6 +1,5 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE TypeOperators #-}
-{-# LANGUAGE OverloadedStrings #-}
 
 -- | This module exposes a Servant-based Network.Wai server for payment
 -- interactions.