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Rendr is a small library that allows you to run your Backbone.js apps seamlessly on both the client and the server. Allow your web server to serve fully-formed HTML pages to any deep link of your app, while preserving the snappy feel of a traditional Backbone.js client-side MVC app.


The documentation website is: If you have any feedback or changes for the documentation please create an issue. The documentation is easy to submit changes to as well! Simply create a fork and use the Github Markdown editor to make and preview any changes, then open just open a Pull Request.

Reporting problems and getting help

Please use the issue tracker to report bugs. For support with using rendr, try asking in the Google group or join #rendr on

Getting Started

To see how to use Rendr to build a simple web app, check out the examples repository for a number of different ways to set up a Rendr app.

Check out the blog post for a more thorough introduction to Rendr.

The Premise

Our hypothesis is that there has to be a better way to build rich web apps today. In the last few years, we've seen more of the application moved to the client-side, with JavaScript representations of views, templates, and models. This can result in interactive, native-style apps, but it also poses challenges. SEO, performance, and maintainability become issues with splitting up your app into two distinct codebases, often in different languages.

The Goals

Rendr is intended to be a building block along the way to this envisioned future of web apps that can be run on either side of the wire according to the needs of your application.

Some specific design goals:

  • Write application logic agnostic to environment
  • Minimize if (server) {...} else {...}
  • Talk to RESTful API
  • Library, not a framework
  • Hide complexity in library
  • No server-side DOM
  • Simple Express middleware

What's Included

Rendr does not attempt to be a fully-fledged, batteries-included application framework. Instead, it follows Backbone's lead by imposing minimal structure, allowing the developer to use the library in the most appropriate way for their application.

Base classes


Inherits from Backbone.View.

Public methods


Environment: shared.

This is where you put any initialization logic.


Environment: shared.


Environment: client.

You should never have to override view.render() unless you're doing something really custom. Instead, you should be able to do anything you need using view.postRender(),


Environment: client.

Here is where you'd put any initialization code that needs to access the DOM. This is a good place for jQuery plugins, sliders, etc.


Environment: shared.

The default implementation returns something reasonable: essentially view.model.toJSON() or {models: view.collection.toJSON()}. This method is easy to override in order to pass custom data to the template, or to decorate the model data.

var MyView = BaseView.extend({
  getTemplateData: function() {
    // Get `super`.
    var data =;
    return _.extend({}, data, {
      someOtherProperty: 'something custom'

Methods you can override for custom view behaviors


Environment: shared.

You should never need to touch this, unless you're heavily customizing the view. Return a function that gets executed with a single data object as an argument.


Environment: shared.

You'll probably never touch this unless you're heavily customizing the view. This defaults to You can return a string to render a different template. This is used by the default implementation of view.getTemplate().


Environment: shared.


Environment: shared.


Environment: shared.

Gets HTML attributes for outer DOM element. Used by view.getHtml().


Inherits from Backbone.Model.


Inherits from Backbone.Collection.


Inherits from Backbone.Model.


Inherits from BaseView. You can change your main content container from this view by changing the contentEl key in the options object when extending BaseAppView

var AppView = BaseAppView.extend({
  options : {
    contentEl : "#mainContent"



Inherits from BaseRouter.


Inherits from BaseRouter.

Rendr Options

Server Config


var config = {
  dataAdapterConfig: {
    'default': {
      host: '',
      protocol: 'https'

  apiPath: '/api',
  appData: { myAttr: 'value'},
  dataAdapter: myDataAdapterInstance,
  defaultEngine: 'js',
  entryPath: process.cwd() + '/myapp'
  errorHandler: function (err, req, res, next){},
  notFoundHandler: function (req, res, next){},
  viewsPath: "/app/views",

Either a dataAdapter or dataAdapterConfig must be present.

  • dataAdapterConfig - This is the standard way of configuring Rendr's built in DataAdapter. See DataAdapter Config

  • dataAdapter - Allows you to override the default DataAdapter and provide your own. The dataAdapterConfig will be ignored.

    Default: RestAdapter which enables Rendr to speak basic REST using HTTP & JSON. This is good for consuming an existing RESTful API that exists externally to your Node app.

  • apiPath Optional - Root of the API proxy's virtual path. Anything after this root will be followed by a -. Example: /api/-/path/to/resource. Allows the proxy to intercept API routes. Can also be a full path to a remote API http://api.myserver

    Default: api

  • appData Optional - Pass any data that needs to be accessible by the client. Accessible from within your Handlebars context app.attributes.myAttr, and also within your views and models

  • defaultEngine Optional - Tell the ViewEngine to load different file types. Example: coffee

    Default: js

  • entryPath Optional - Root path of your app.

    Default: process.cwd() + '/' - Current working directory of the node process

  • errorHandler Optional Callback for Express.js errors.

    Example function (err, req, res, next) { }

  • notFoundHandler Optional - Callback for Express.js not found errors

    Example function (req, res, next) { }

  • viewEngine Optional - Provides a way to set a custom Express.js view engine

    Default: new ViewEngine() - Rendr provides a built in ViewEngine that hooks to Template Adapters. See rendr-handlebars.

  • viewsPath Optional - Override where your views are stored. Path is relative to entryPath.

    Default: app/views

DataAdapter Config

This configuration is passed to the current DataAdapter, which by default is the RestAdapter.



var dataAdapterConfig = {
  host: '',
  protocol: 'https'


var dataAdapterConfig = {
  'default': {
    host: '',
    protocol: 'https'
  'travis-ci': {
    host: '',
    protocol: 'https'

Example of how a Backbone model can be configured to select one of the DataAdapter configs.

Note: This example assumes you are using the RestAdapter.

module.exports = Base.extend({
  url: '/repos/:owner/:name',
  api: 'travis-ci'
}); = 'Build';

Adding middleware to Rendr's Express

You can optionally add any custom middleware that has to access req.rendrApp but should run before the Rendr routes by calling configure after createServer.

rendr.configure(function(expressApp) {



Template Adapters

Provides a way for Rendr to utilize custom html template engines (see also Template Engines section below). Rendr's ViewEngine will delegate to the Template Adapter. You can build your own to provide your template engine of choice (i.e. Jade, Underscore templates, etc).

####Available Template Adapters

####Using Custom Adapters

You can tell Rendr which Template Adapter to use. This represents the node-module that contains the adapter.

// /app/app.js

module.exports = BaseApp.extend({
  defaults: {
    templateAdapter: 'rendr-emblem'


Template Engines

While Template Adapters provide the layer of abstraction that allow you to use your favorite template engine in a Rendr app, the Template Engine option itself will tell the app which version to use exactly. The default is set to be Handlebars, which is currently supported by the Rendr-handlebars adapter until version 2.0.0. When setting up your Rendr app, you'll need to add your Template Engine of choice to package.json.


// /package.json

"dependencies": {
  "express": "^4.12.0",
  "handlebars": "^2.0.0"
  "qs2": "~0.6.6",

####Using Custom Template Engines

You can tell Rendr which Template Engine to use. This represents the node-module that contains the engine.

// /app/app.js

module.exports = BaseApp.extend({
  defaults: {
    templateEngine: 'handlebars'


Express middleware

There are a few middleware functions included. Use some or all of these, or use your own.


What's Not Included

Express app

Rather than owning your entire Express app, Rendr simply provides some useful middleware that you can mount into your existing Express app.


Rendr uses the native ECMAScript 5 methods, Function.prototype.bind, Object.create, etc. If you plan to support older browsers, such as IE<=8, you should include the lovely es5-shim (and es5-sham) libraries as client-side dependencies.


We'd love to see what the community can come up with! There are no doubt a number of developers who are tackling this same problem, and we can learn from each other. If you have a bug fix or feature proposal, submit a pull request with a clear description of the change, plus tests.

Rendr was originally developed by @braitz and @spikebrehm, and now has a healthy list of contributors.

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.



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