Carlo: Web rendering surface for Node applications by Google Chrome

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Carlo – headful Node app framework

NPM carlo package
Install Size

Carlo provides Node applications with the rich rendering capabilities powered by the Google Chrome browser.
It uses Puppeteer project to communicate with the locally installed browser instance, provides remote call infrastructure for communication between Node and the browser.


What can I do?

With Carlo, you can create hybrid applications that use Web stack for rendering and Node for capabilities:

How does it work?
  • Carlo locates Google Chrome installed locally
  • Launches it and establishes connection to Chrome over the process pipe
  • Exposes high level API for rendering in Chrome in Node environment


Install Carlo

Carlo requires at least Node v7.6.0.

Example – Display local environment

Save file as example.js

const carlo = require('carlo');

(async () => {
  // Launch the browser.
  const app = await carlo.launch();

  // Tell carlo where your web files are located.

  // Expose 'env' function in the web environment.
  await app.exposeFunction('env', _ => process.env);

  // Navigate to the main page of your app.
  await app.load('example.html');

Save file as example.html

async function run() {
  // Call the function that was exposed in Node.
  const data = await env();
  for (const type in data) {
    const div = document.createElement('div');
    div.textContent = `${type}: ${data[type]}`;
<body onload="run()">

Run your application:

Check out systeminfo and terminal examples with richer UI and RPC-based communication between the Web and Node under the examples folder.


Check out API to get familiar with Carlo API.

Contributing to Carlo

Check out contributing guide to get an overview of Carlo development.


Q: What was the motivation behind this project when we already have Electron and NW.js? How this differs from these platforms, how it helps to achieve something that’s not possible/harder with these two?

  • One of the motivations is to demonstrate how browser installed locally can be used with Node out of the box.
  • Unlike with Electron, Node v8 and Chrome v8 engines are decoupled in Carlo, providing a maintainable model with the ability of the independent updates of the underlying components. Carlo is less about branding and is more about productivity + giving the control over bundling to the user.

Q: Can Node app using Carlo be packaged as a Desktop app?

One can use the pkg project to package their Node app as a Desktop app. Carlo does not provide the branding configurability such as application icon or customizable menus, it focuses on the productivity and Web/Node interoperability instead. Check out the systeminfo example and call pkg package.json in it to see how it works.

Q: What happens if the user does not have Chrome installed?

Carlo prints error message when it can’t locate Chrome.

Q: What is the minimum Chrome version that Carlo supports?

Chrome Stable channel, versions 70.* are supported.

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