diff --git a/packages/xo-server-auth-ldap/package.json b/packages/xo-server-auth-ldap/package.json
index c6add5845..d50357213 100644
--- a/packages/xo-server-auth-ldap/package.json
+++ b/packages/xo-server-auth-ldap/package.json
@@ -27,7 +27,6 @@
   ],
   "dependencies": {
     "babel-runtime": "^6.3.19",
-    "bluebird": "^3.1.1",
     "event-to-promise": "^0.6.0",
     "exec-promise": "^0.5.1",
     "fs-promise": "^0.3.1",
diff --git a/packages/xo-server-auth-ldap/src/index.js b/packages/xo-server-auth-ldap/src/index.js
index 856a2be56..4a8721de0 100644
--- a/packages/xo-server-auth-ldap/src/index.js
+++ b/packages/xo-server-auth-ldap/src/index.js
@@ -3,7 +3,6 @@
 import eventToPromise from 'event-to-promise'
 import { createClient } from 'ldapjs'
 import { escape } from 'ldapjs/lib/filters/escape'
-import { promisify } from 'bluebird'
 import { readFile } from 'fs-promise'
 
 // ===================================================================
@@ -14,6 +13,22 @@ const bind = (fn, thisArg) => function () {
 
 const noop = () => {}
 
+export const promisify = (fn, thisArg) => function () {
+  const { length } = arguments
+  const args = new Array(length + 1)
+  for (let i = 0; i < length; ++i) {
+    args[i] = arguments[i]
+  }
+
+  return new Promise((resolve, reject) => {
+    args[length] = (error, result) => error
+      ? reject(error)
+      : resolve(result)
+
+    fn.apply(thisArg || this, args)
+  })
+}
+
 // -------------------------------------------------------------------
 
 const VAR_RE = /\{\{([^}]+)\}\}/g