A nifty javascript sandbox for node.js

Node Sandbox

A nifty javascript sandbox for node.js.

  • Can be used to execute untrusted code.
  • Support for timeouts (e.g. prevent infinite loops)
  • Support for memory errors (and memory errors)
  • Handles errors gracefully
  • Restricted code (cannot access node.js methods)
  • Supports console.log and print utility methods
  • Supports interprocess messaging with the sandboxed code

Be sure to check out example/example.js

var s = new Sandbox();'1 + 1 + " apples"', function(output) {
  // output.result == "2 apples" 
  • code {String} — string of Javascript to be executed.
  • hollaback {Function} — called after execution with a single argument, output.
    • output is an object with two properties: result and console. The result property is an inspected string of the return value of the code. The console property is an array of all console output.

For example, given the following code:

function add(ab){
  return a + b;
add(20, 22);

The resulting output object is:

  result: "42",
  console: ["20", "22"]
  • message {String} - message to send to the sandboxed code

For example, the following code will send a message from outside of the sandbox in and then the sandboxed code will respond with its own message. Note that the sandboxed code handles incoming messages by defining a global onmessage function and can send messages to the outside using the postMessage function.

Sandboxed code:

onmessage = function(message){
  if (message === 'hello from outside') {
    postMessage('hello from inside');


var sandbox = new Sandbox();;
sandbox.on('message', function(message){
  // Handle message sent from the inside
  // In this example message will be 'hello from inside'
sandbox.postMessage('hello from outside');

The process will ONLY be considered finished if onmessage is NOT a function. If onmessage is defined the sandbox will assume that it is waiting for an incoming message.

Let's get it! The easiest way is through npm:

npm install sandbox

Or if you'd like to play with the code, see the examples, run the tests, what-the-fuck-ever...

git clone git://

And run some examples:

node example/example.js

To run the tests simply run the test file with node.

npm test

Sandbox is UNLICENSED.