diff --git a/hledger-web/hledger-web.hs b/hledger-web/hledger-web.hs
index fb4ab676a..8d27110a0 100644
--- a/hledger-web/hledger-web.hs
+++ b/hledger-web/hledger-web.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE CPP #-}
+{-# LANGUAGE CPP, OverloadedStrings #-}
 {-|
 
 hledger-web - a hledger add-on providing a web interface.