diff --git a/src/applications/search/config/PhabricatorSearchConfigOptions.php b/src/applications/search/config/PhabricatorSearchConfigOptions.php
--- a/src/applications/search/config/PhabricatorSearchConfigOptions.php
+++ b/src/applications/search/config/PhabricatorSearchConfigOptions.php
@@ -32,6 +32,10 @@
         ->setLocked(true)
         ->setDescription(pht('Elastic Search host.'))
         ->addExample('http://elastic.example.com:9200/', pht('Valid Setting')),
+      $this->newOption('search.elastic.namespace', 'string', 'phabricator')
+        ->setLocked(true)
+        ->setDescription(pht('Elastic Search index.'))
+        ->addExample('phabricator2', pht('Valid Setting')),
     );
   }
 
diff --git a/src/applications/search/engine/PhabricatorSearchEngineElastic.php b/src/applications/search/engine/PhabricatorSearchEngineElastic.php
--- a/src/applications/search/engine/PhabricatorSearchEngineElastic.php
+++ b/src/applications/search/engine/PhabricatorSearchEngineElastic.php
@@ -2,10 +2,12 @@
 
 final class PhabricatorSearchEngineElastic extends PhabricatorSearchEngine {
   private $uri;
+  private $index;
   private $timeout;
 
-  public function __construct($uri) {
+  public function __construct($uri, $index) {
     $this->uri = $uri;
+    $this->index = $index;
   }
 
   public function setTimeout($timeout) {
@@ -51,7 +53,7 @@
     }
 
     $this->executeRequest(
-      "/phabricator/{$type}/{$phid}/",
+      "/{$type}/{$phid}/",
       $spec,
       $is_write = true);
   }
@@ -59,7 +61,7 @@
   public function reconstructDocument($phid) {
     $type = phid_get_type($phid);
 
-    $response = $this->executeRequest("/phabricator/{$type}/{$phid}", array());
+    $response = $this->executeRequest("/{$type}/{$phid}", array());
 
     if (empty($response['exists'])) {
       return null;
@@ -210,10 +212,10 @@
         PhabricatorSearchApplicationSearchEngine::getIndexableDocumentTypes());
     }
 
-    // Don't use '/phabricator/_search' for the case that there is something
+    // Don't use '/_search' for the case that there is something
     // else in the index (for example if 'phabricator' is only an alias to
-    // some bigger index).
-    $uri = '/phabricator/'.implode(',', $types).'/_search';
+    // some bigger index). Use '/$types/_search' instead.
+    $uri = '/'.implode(',', $types).'/_search';
 
     try {
       $response = $this->executeRequest($uri, $this->buildSpec($query));
@@ -238,10 +240,10 @@
 
   private function executeRequest($path, array $data, $is_write = false) {
     $uri = new PhutilURI($this->uri);
+    $uri->setPath($this->index);
+    $uri->appendPath($path);
     $data = json_encode($data);
 
-    $uri->setPath($path);
-
     $future = new HTTPSFuture($uri, $data);
     if ($is_write) {
       $future->setMethod('PUT');
diff --git a/src/applications/search/selector/PhabricatorDefaultSearchEngineSelector.php b/src/applications/search/selector/PhabricatorDefaultSearchEngineSelector.php
--- a/src/applications/search/selector/PhabricatorDefaultSearchEngineSelector.php
+++ b/src/applications/search/selector/PhabricatorDefaultSearchEngineSelector.php
@@ -6,7 +6,8 @@
   public function newEngine() {
     $elastic_host = PhabricatorEnv::getEnvConfig('search.elastic.host');
     if ($elastic_host) {
-      return new PhabricatorSearchEngineElastic($elastic_host);
+      $elastic_index = PhabricatorEnv::getEnvConfig('search.elastic.namespace');
+      return new PhabricatorSearchEngineElastic($elastic_host, $elastic_index);
     }
     return new PhabricatorSearchEngineMySQL();
   }