Tamper: Data Chrome

Let’s walk through a practical example: you want to change a user_id parameter from 1001 to 1002 in a POST request to see if you can access another user’s data.

Step 1: Install Requestly from the Chrome Web Store.

Step 2: Open Requestly dashboard and create a new "Modify Request" rule.

Step 3: Set the URL filter – e.g., *://api.example.com/users/* tamper data chrome

Step 4: Choose modification type:

Step 5: In the body modification field, set:
user_id: 1001 → Replace with 1002

Step 6: Save the rule and enable it.

Step 7: Use Chrome normally. Every matching request will be altered before leaving your browser. Use DevTools Network tab to confirm the change.

Data tampering is used for two primary purposes:

  "manifest_version": 3,
  "name": "Tamper Data - Request Interceptor",
  "version": "1.0.0",
  "description": "Intercept and modify HTTP request headers before they are sent.",
  "permissions": [
    "declarativeNetRequest",
    "declarativeNetRequestFeedback",
    "storage",
    "activeTab"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": 
    "service_worker": "background.js"
  ,
  "action": 
    "default_popup": "popup.html",
    "default_title": "Tamper Data",
    "default_icon": 
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
,
  "icons": 
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  ,
  "minimum_chrome_version": "88"

For serious security researchers or QA engineers, browser extensions often have limitations. They cannot intercept certain background processes, and the browser sandbox restricts them. The industry standard for "tampering with data" today isn't an extension at all—it’s a proxy. Let’s walk through a practical example: you want

Burp Suite Community Edition is the professional evolution of what tools like Tamper Data started.

For anyone moving on from simple browser add-ons, learning to use an intercepting proxy is the necessary next step.

While primarily for modifying request headers, ModHeader is lightweight and perfect for specific tampering tasks (changing User-Agent, adding API keys). Step 5: In the body modification field, set: