diff --git a/lib/index.js b/lib/index.js
index 0026236..10bd513 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -60,6 +60,7 @@ module.exports = function (config, log, since) {
 
     var doc = change.doc
     var es_doc_url = config.elasticsearch + '/' + change.id
+    if (config.key) es_doc_url = config.elasticsearch + '/' + doc[config.key]
     if (config.urlTemplate) es_doc_url = run_compile(es_doc_url, doc, log)
     if (doc._deleted) return handle_delete(config, es_doc_url, change, log, onDone, endTask)