diff --git a/lib/Modeler.js b/lib/Modeler.js
index 68c981a7..27f026f0 100644
--- a/lib/Modeler.js
+++ b/lib/Modeler.js
@@ -18,17 +18,13 @@ function Modeler(options) {
 
 Modeler.prototype = Object.create(Viewer.prototype);
 
-Modeler.prototype.createDiagram = function(modules) {
-  return Viewer.prototype.createDiagram.call(this, modules || Modeler.modules);
-};
-
-Modeler.modules = [
+// modules that comprise the bpmn modeler
+Modeler.prototype._modules = Modeler.prototype._modules.concat([
   // TODO (nre): buggy in conjunction with zoomscroll / move canvas
   // require('diagram-js/lib/features/move'),
   require('./features/label-editing'),
-  require('./core'),
   require('./features/zoomscroll'),
   require('./features/movecanvas')
-];
+]);
 
 module.exports = Modeler;
diff --git a/lib/Viewer.js b/lib/Viewer.js
index a0bd75e7..00841e0e 100644
--- a/lib/Viewer.js
+++ b/lib/Viewer.js
@@ -141,12 +141,21 @@ Viewer.prototype.saveSVG = function(options, done) {
 Viewer.prototype.get = function(name) {
 
   if (!this.diagram) {
-    return null;
+    throw new Error('no diagram loaded');
   }
 
   return this.diagram.get(name);
 };
 
+Viewer.prototype.invoke = function(fn) {
+
+  if (!this.diagram) {
+    throw new Error('no diagram loaded');
+  }
+
+  return this.diagram.invoke(fn);
+};
+
 Viewer.prototype.importDefinitions = util.failSafeAsync(function(definitions, done) {
 
   var diagram = this.diagram;
@@ -172,12 +181,23 @@ Viewer.prototype.initDiagram = function(diagram) {
 
 Viewer.prototype.createDiagram = function(modules) {
 
+  modules = [].concat(modules || this.getModules());
+
+  // add self as an available service
+  modules.unshift({
+    bpmnjs: [ 'value', this ]
+  });
+
   return new Diagram({
     canvas: { container: this.container },
-    modules: modules || Viewer.modules
+    modules: modules
   });
 };
 
+Viewer.prototype.getModules = function() {
+  return this._modules;
+};
+
 Viewer.prototype.clear = function() {
   var diagram = this.diagram;
 
@@ -198,7 +218,8 @@ Viewer.prototype.on = function(event, handler) {
   }
 };
 
-Viewer.modules = [
+// modules that comprise the bpmn viewer
+Viewer.prototype._modules = [
   require('./core')
 ];
 
diff --git a/test/spec/browser/ModelerSpec.js b/test/spec/browser/ModelerSpec.js
index f33eea5e..4a163938 100644
--- a/test/spec/browser/ModelerSpec.js
+++ b/test/spec/browser/ModelerSpec.js
@@ -17,28 +17,23 @@ describe('Modeler', function() {
   });
 
 
-  it('should import simple process', function(done) {
+  function createModeler(xml, done) {
+    var modeler = new Modeler({ container: container });
 
-    var xml = fs.readFileSync('test/fixtures/bpmn/simple.bpmn', 'utf8');
-
-    var renderer = new Modeler(container);
-
-    renderer.importXML(xml, function(err) {
-      done(err);
+    modeler.importXML(xml, function(err) {
+      done(err, modeler);
     });
+  }
+
+  it('should import simple process', function(done) {
+    var xml = fs.readFileSync('test/fixtures/bpmn/simple.bpmn', 'utf8');
+    createModeler(xml, done);
   });
 
 
   it('should import empty definitions', function(done) {
-
     var xml = fs.readFileSync('test/fixtures/bpmn/empty-definitions.bpmn', 'utf8');
-
-    var renderer = new Modeler(container);
-
-    renderer.importXML(xml, function(err) {
-
-      done(err);
-    });
+    createModeler(xml, done);
   });
 
 
@@ -56,4 +51,22 @@ describe('Modeler', function() {
     });
   });
 
+
+  describe('dependency injection', function() {
+
+    it('should be available via di as <bpmnjs>', function(done) {
+
+      debugger;
+
+      var xml = fs.readFileSync('test/fixtures/bpmn/simple.bpmn', 'utf8');
+
+      createModeler(xml, function(err, modeler) {
+
+        expect(modeler.get('bpmnjs')).toBe(modeler);
+        done(err);
+      });
+    });
+
+  });
+
 });
\ No newline at end of file
diff --git a/test/spec/browser/ViewerSpec.js b/test/spec/browser/ViewerSpec.js
index c6077bdd..e293a339 100644
--- a/test/spec/browser/ViewerSpec.js
+++ b/test/spec/browser/ViewerSpec.js
@@ -73,6 +73,23 @@ describe('Viewer', function() {
   });
 
 
+  describe('dependency injection', function() {
+
+    it('should be available via di as <bpmnjs>', function(done) {
+
+      var xml = fs.readFileSync('test/fixtures/bpmn/simple.bpmn', 'utf8');
+
+      createViewer(xml, function(err, viewer) {
+
+        expect(viewer.get('bpmnjs')).toBe(viewer);
+
+        done(err);
+      });
+    });
+
+  });
+
+
   describe('export', function() {
 
     it('should export svg', function(done) {