diff --git a/src/PostgREST/Config.hs b/src/PostgREST/Config.hs
index 8c60ef553..5aaccf9a7 100644
--- a/src/PostgREST/Config.hs
+++ b/src/PostgREST/Config.hs
@@ -47,7 +47,7 @@ data AppConfig = AppConfig {
 
 argParser :: Parser AppConfig
 argParser = AppConfig
-  <$> argument str (help "(REQUIRED) database connection string" <> metavar "DB_URL")
+  <$> argument str (help "(REQUIRED) database connection string, e.g. postgres://user:pass@host:port/db" <> metavar "DB_URL")
   <*> strOption    (long "anonymous"  <> short 'a' <> help "(REQUIRED) postgres role to use for non-authenticated requests" <> metavar "ROLE")
   <*> strOption    (long "schema"     <> short 's' <> help "schema to use for API routes" <> metavar "NAME" <> value "public" <> showDefault)
   <*> option auto  (long "port"       <> short 'p' <> help "port number on which to run HTTP server" <> metavar "PORT" <> value 3000 <> showDefault)