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This is a playground to test code. It runs a full Node.js environment and already has all of npm’s 400,000 packages pre-installed, including with all npm packages installed. Try it out:

var socketIoCap = require("")

This service is provided by RunKit and is not affiliated with npm, Inc or the package authors. v2.0.2

Proxy server for capturing and modifying data

Proxy server for capturing and modifying data.


npm install


const proxy = require('').createProxy().listen(8889);
const proxy = require('').createProxy({/*options*/});

proxy.on('conn', ctx => {
  ctx.headers.referer = '';

proxy.on('packet', (p, {cSocket, pSocket}) => {
  proxy.showPacket(p, false);

  if (p.event == 'my-message') {
    p.args[0] = 'hello world';

  if (p.event == 'test' && p.fromServer) {
    p.drop = true;
    cSocket.emit('custom-message', 'hello world');


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