diff --git a/lib/file.js b/lib/file.js
index 55d11967..e7b4ca77 100644
--- a/lib/file.js
+++ b/lib/file.js
@@ -25,6 +25,15 @@ var file = {
         });
       });
     });
+  },  
+  /**
+   * isZippedBuffer return callback(true) if the buffer is zipped
+   * @param  {Buffer}   buffer file path
+   * @param  {Function} callback(err, isZipped)
+   */
+  isZippedBuffer : function (buffer, callback) {
+    var _buf = buffer;
+    callback(null, (buffer.slice(0, 2).toString() === 'PK'));
   },
 
   /**
@@ -47,7 +56,7 @@ var file = {
 
   /**
    * Unzip a file
-   * @param  {String}   filePath              file to unzip
+   * @param  {String}   filePath              file or buffer to unzip
    * @param  {Function} callback(err, files)  files is an array of files ['name':'filename', 'buffer':Buffer]
    */
   unzip : function (filePath, callback) {
@@ -130,9 +139,44 @@ var file = {
     _zip.end();
   },
 
+  /**
+   * 
+   * @param {Buffer} buffer document as a buffer
+   * @param {*} callback 
+   * @returns 
+   */
+  openTemplateBuffer : function (buffer, callback) {
+    file.isZippedBuffer(buffer, function(err, isZipped) {
+      if (err) return callback(err);
+      var _template = {
+        isZipped,
+        filename   : 'template-from-buffer',
+        embeddings : [],
+        files      : []
+      };
+      if (isZipped === true) {
+        var _filesToUnzip = [{
+          name : '',
+          data : buffer
+        }];
+        return unzipFiles(_template, _filesToUnzip, callback);
+      }
+      else {
+        var _file = {
+          name     : 'file-from-buffer',
+          data     : buffer,
+          isMarked : true,
+          parent   : ''
+        };
+        _template.files.push(_file);
+        return callback(err, _template);
+      }    
+    })
+  },
+
   /**
    * Open a template  (zipped or not). It will find the template and convert the buffer into strings if it contains xml
-   * @param  {String}   templateId               template name (with or without the path)
+   * @param  {String}   templateId               template name (with or without the path) or buffer. When buffer is used, extension option must be provided
    * @param  {Function} callback(err, template)
    */
   openTemplate : function (templateId, callback) {
@@ -142,6 +186,9 @@ var file = {
       embeddings : [],
       files      : []
     };
+    if(Buffer.isBuffer(templateId)){
+      return file.openTemplateBuffer(templateId, callback)
+    }
     if (templateId instanceof Object) {
       // accept already dezipped files (for test purpose)
       return callback(null, templateId);
diff --git a/lib/index.js b/lib/index.js
index 9819bd57..8a8ec490 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -194,9 +194,8 @@ var carbone = {
           return callback(err, null);
         }
         // Determine the template extension.
-        var _extension = file.detectType(template);
         // It takes the user defined one, or use the file type.
-        options.extension = optionsRaw.extension || _extension;
+        options.extension = optionsRaw.extension || file.detectType(template);
         if (options.extension === null) {
           return callback('Unknown input file type. It should be a docx, xlsx, pptx, odt, ods, odp, xhtml, html or an xml file');
         }
diff --git a/test/test.file.js b/test/test.file.js
index bcbf09dc..f1c44678 100644
--- a/test/test.file.js
+++ b/test/test.file.js
@@ -138,6 +138,24 @@ describe('file', function () {
       });
     });
   });
+  
+  describe('isZippedBuffer', function () {
+    it('should return true if the file is zipped', function (done) {
+      var buffer = fs.readFileSync(path.resolve('./test/datasets/test_word_render_A.docx'));
+      file.isZippedBuffer(buffer, function (err, isZipped) {
+        helper.assert(isZipped, true);
+        done();
+      });
+    });
+    it('should return false if the file is not zipped', function (done) {
+      var buffer = fs.readFileSync(path.resolve('./test/datasets/test_word_render_2003_XML.xml'));
+      file.isZippedBuffer(buffer, function (err, isZipped) {
+        helper.assert(isZipped, false);
+        done();
+      });
+    });
+  });
+  
 
   describe('unzip', function () {
     it('should unzip a file and return a array which contain its content', function (done) {
@@ -493,6 +511,31 @@ describe('file', function () {
         done();
       });
     });
+
+    it('should open embedded xlsx buffer', function (done) {
+      const buffer = fs.readFileSync(path.resolve(__dirname, 'datasets', 'test_word_with_embedded_excel.docx'))
+      file.openTemplate(buffer, function (err, template) {
+        helper.assert(err, null);
+        helper.assert(template.isZipped, true);
+        helper.assert(template.files.length, 29);
+        helper.assert(template.embeddings.length, 1);
+        helper.assert(template.embeddings, ['word/embeddings/Feuille_de_calcul_Microsoft_Excel1.xlsx']);
+        var _filesFromDocx = template.files.filter((file) => {
+          return file.parent === '';
+        });
+        helper.assert(_filesFromDocx.length, 16);
+        var _filesFromXslx = template.files.filter((file) => {
+          return file.parent === 'word/embeddings/Feuille_de_calcul_Microsoft_Excel1.xlsx';
+        });
+        helper.assert(_filesFromXslx.length, 13);
+        var _oneFileOfXlsx = _filesFromXslx.filter((file) => {
+          return file.name === 'xl/tables/table1.xml';
+        });
+        helper.assert(_oneFileOfXlsx.length, 1);
+        helper.assert(/Tableau1/.test(_oneFileOfXlsx[0].data), true);
+        done();
+      });
+    });
     /* it.skip('should detect files which contains markers (not all xml)');*/
   });