Tampery – Tamper browser reuqests like a Pro

Chrome Web Store

Tampery is a browser extension to tamper browser requests in flight. It is programmable, which means you could write your own script to intercept, block, or modify browser requests. There is also a dashboard to manage all scripts.


Install it from Chrome Web Store


There are some simple examples to show how it works:


Tampery use chrome.webRequest API under the hood. Basically, every script should export an object as default, which has lifecycle, callback, filter and extraInfoSpec as keys. For example, if we want to change User-Agent in request headers, we could create a script as follows:

const myUserAgent =
  'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1'

export default {
  lifecycle: 'onBeforeSendHeaders',
  callback: ({ requestHeaders }) => {
    for (var i = 0; i < requestHeaders.length; ++i) {
      // Find the key named `User-Agent` and change its value
      if (requestHeaders[i].name.toLowerCase() === 'user-agent') {
        requestHeaders[i].value = myUserAgent
    return { requestHeaders } // Return to change headers
  filter: {
    urls: ['<all_urls>'], // Specify it takes effect on which URLs
  extraInfoSpec: [
    'blocking', // Add `blocking` here since we want to change request headers

For more information, see documentation of webRequest API of Chrome and Firefox



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