diff --git a/src/main/scala/net/kemitix/s3thorp/S3Client.scala b/src/main/scala/net/kemitix/s3thorp/S3Client.scala
new file mode 100644
index 0000000..7ce20cf
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/S3Client.scala
@@ -0,0 +1,9 @@
+package net.kemitix.s3thorp
+
+import net.kemitix.s3thorp.Sync.{Hash, LastModified}
+
+trait S3Client {
+
+  def objectHead(bucket: String, key: String): (Hash, LastModified)
+
+}