diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,8 @@
+0.1.1:
+
+  + Server certificate validator can be specified for confTransport.
+  * Re-export default validator from X509.
+
 0.1:
 
   + Initial version.
diff --git a/soap-tls.cabal b/soap-tls.cabal
--- a/soap-tls.cabal
+++ b/soap-tls.cabal
@@ -1,5 +1,5 @@
 name:                soap-tls
-version:             0.1.0.0
+version:             0.1.1.0
 synopsis:            TLS-enabled SOAP transport (using tls package)
 description:         TLS-enabled SOAP transport (using tls package)
 homepage:            https://bitbucket.org/dpwiz/haskell-soap
@@ -19,9 +19,12 @@
   exposed-modules:     Network.SOAP.Transport.HTTP.TLS
   build-depends:       base >=4.6 && <5
                      , soap >= 0.2.2 && < 0.3
+                     , http-client >= 0.2 && < 0.3
                      , http-client-tls >= 0.2 && < 0.3
                      , tls >= 1.2 && < 2
                      , connection >= 0.2 && < 0.3
+                     , x509
+                     , x509-store
                      , x509-validation
                      , text
                      , configurator
diff --git a/src/Network/SOAP/Transport/HTTP/TLS.hs b/src/Network/SOAP/Transport/HTTP/TLS.hs
--- a/src/Network/SOAP/Transport/HTTP/TLS.hs
+++ b/src/Network/SOAP/Transport/HTTP/TLS.hs
@@ -1,13 +1,21 @@
 -- | SSL-enabled http transport with support for https requests and client certificates.
 
-module Network.SOAP.Transport.HTTP.TLS where
+module Network.SOAP.Transport.HTTP.TLS
+    ( confTransport
+    , makeSettings
+    -- * Certificate validation
+    , ServerCertCallback, validateDefault
+    ) where
 
+import Network.HTTP.Client (ManagerSettings)
 import Network.SOAP.Transport (Transport)
 import Network.SOAP.Transport.HTTP (confTransportWith)
 
 import Network.HTTP.Client.TLS
 import Network.TLS
-import Data.X509.Validation as X509
+import Data.X509
+import Data.X509.CertificateStore
+import Data.X509.Validation
 import Network.Connection (TLSSettings(..))
 
 import           Data.Monoid
@@ -16,13 +24,27 @@
 import qualified Data.Configurator as Conf
 import           Data.Configurator.Types (Config)
 
-confTransport :: Text -> Config -> IO Transport
-confTransport section conf = do
+type ServerCertCallback = CertificateStore
+                       -> ValidationCache
+                       -> ServiceID
+                       -> CertificateChain
+                       -> IO [FailedReason]
+
+-- | Initialize a SOAP HTTP transport with HTTPS support using tls.
+confTransport :: Text   -- ^ Section name containing transport settings.
+              -> Config
+              -> ServerCertCallback
+              -> IO Transport
+confTransport section conf onSC = do
     cert <- Conf.lookup conf (section <> ".client_cert")
     key <- Conf.lookup conf (section <> ".client_key")
-    settings <- makeSettings cert key X509.validateDefault
+    settings <- makeSettings cert key onSC
     confTransportWith settings section conf id id
 
+makeSettings :: Maybe FilePath
+             -> Maybe FilePath
+             -> ServerCertCallback
+             -> IO ManagerSettings
 makeSettings (Just certFile) (Just keyFile) onSC = do
     creds <- either error Just `fmap` credentialLoadX509 certFile keyFile