diff --git a/lib/includes.polyfill.js b/lib/includes.polyfill.js
new file mode 100644
index 0000000..6a50b25
--- /dev/null
+++ b/lib/includes.polyfill.js
@@ -0,0 +1,51 @@
+// https://tc39.github.io/ecma262/#sec-array.prototype.includes
+if (!Array.prototype.includes) {
+    Object.defineProperty(Array.prototype, 'includes', {
+      value: function(searchElement, fromIndex) {
+  
+        if (this == null) {
+          throw new TypeError('"this" is null or not defined');
+        }
+  
+        // 1. Let O be ? ToObject(this value).
+        var o = Object(this);
+  
+        // 2. Let len be ? ToLength(? Get(O, "length")).
+        var len = o.length >>> 0;
+  
+        // 3. If len is 0, return false.
+        if (len === 0) {
+          return false;
+        }
+  
+        // 4. Let n be ? ToInteger(fromIndex).
+        //    (If fromIndex is undefined, this step produces the value 0.)
+        var n = fromIndex | 0;
+  
+        // 5. If n ≥ 0, then
+        //  a. Let k be n.
+        // 6. Else n < 0,
+        //  a. Let k be len + n.
+        //  b. If k < 0, let k be 0.
+        var k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);
+  
+        function sameValueZero(x, y) {
+          return x === y || (typeof x === 'number' && typeof y === 'number' && isNaN(x) && isNaN(y));
+        }
+  
+        // 7. Repeat, while k < len
+        while (k < len) {
+          // a. Let elementK be the result of ? Get(O, ! ToString(k)).
+          // b. If SameValueZero(searchElement, elementK) is true, return true.
+          if (sameValueZero(o[k], searchElement)) {
+            return true;
+          }
+          // c. Increase k by 1. 
+          k++;
+        }
+  
+        // 8. Return false
+        return false;
+      }
+    });
+  }
diff --git a/lib/ovh.es5.js b/lib/ovh.es5.js
index 98c51af..00e75a7 100644
--- a/lib/ovh.es5.js
+++ b/lib/ovh.es5.js
@@ -26,6 +26,9 @@
  */
 'use strict';
 
+// String.includes polyfill
+require('./includes.polyfill');
+
 var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol" ? function (obj) { return typeof obj; } : function (obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol ? "symbol" : typeof obj; };
 
 var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();
@@ -51,6 +54,7 @@ var Ovh = function () {
     this.timeout = params.timeout;
     this.apiTimeDiff = params.apiTimeDiff || null;
     this.endpoint = params.endpoint || null;
+    this.noAuthPaths = params.noAuthPaths || ['/auth/credential', '/auth/time'];
 
     // Preconfigured API endpoints
     if (this.endpoint) {
@@ -363,7 +367,7 @@ var Ovh = function () {
         }
       }
 
-      if (path.indexOf('/auth') < 0) {
+      if (!this.noAuthPaths.includes(path)) {
         options.headers['X-Ovh-Timestamp'] = Math.round(Date.now() / 1000) + this.apiTimeDiff;
 
         // Sign request
diff --git a/lib/ovh.es6.js b/lib/ovh.es6.js
index 3d0013b..bc3fe34 100644
--- a/lib/ovh.es6.js
+++ b/lib/ovh.es6.js
@@ -26,6 +26,9 @@
  */
 'use strict';
 
+// String.includes polyfill
+require('./includes.polyfill');
+
 let https = require('https'),
   Bluebird = require('bluebird'),
   querystring = require('querystring'),
@@ -43,6 +46,7 @@ class Ovh {
     this.timeout = params.timeout;
     this.apiTimeDiff = params.apiTimeDiff || null;
     this.endpoint = params.endpoint || null;
+    this.noAuthPaths = params.noAuthPaths || ['/auth/credential', '/auth/time'];
 
     // Preconfigured API endpoints
     if (this.endpoint) {
@@ -356,7 +360,7 @@ class Ovh {
       }
     }
 
-    if (path.indexOf('/auth') < 0) {
+    if (!this.noAuthPaths.includes(path)) {
       options.headers['X-Ovh-Timestamp'] = Math.round(Date.now() / 1000) + this.apiTimeDiff;
 
       // Sign request
@@ -487,4 +491,4 @@ class Ovh {
 
 module.exports = function (params) {
   return new Ovh(params || {});
-};
\ No newline at end of file
+};