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Browser Developer Tools

Tool manual · Kali & common usage

Web testing · Beginner · Web testing lane

BeginnerWeb Inspection
Authorized usage only. Capture and inspect traffic only on systems and networks you own or have written permission to analyze.

What is Browser Developer Tools?

Built-in browser Developer Tools (Chrome/Edge/Firefox) for inspecting HTML, JS, network calls, cookies, and storage.

First stop for understanding how a web page talks to its backend — no extra install.

Official website: Browser Developer Tools · Documentation

When do you use it?

  • Check cookies (Secure, HttpOnly, SameSite).
  • Watch XHR/fetch failures, status codes, headers.
  • Debug front-end auth flows.

Who uses it?

  • AppSec engineers
  • Bug bounty hunters (in-scope)
  • Penetration testers

How do you use it? (typical flow)

  1. Install Browser Developer Tools using the steps below (prefer Kali package or official installer).
  2. Confirm you have authorization for the target (lab VM, own system, or written scope).
  3. Run --help / man (or the Help section) to see current flags for your version.
  4. Start with a safe example from Basic commands against localhost or an authorized lab target.
  5. Record what you ran, what you observed, and any follow-up (filter, report, remediation).

Help & manual (like man / --help)

Every serious tool has a built-in way to look up flags. Learn these first so you are not stuck memorizing every option.

  1. 1. Chrome DevTools docs

    https://developer.chrome.com/docs/devtools

    Official guide.

  2. 2. Open tools

    F12 or Ctrl+Shift+I

    Keyboard shortcut.

Kali Linux

Use Firefox/Chromium on Kali — press F12. No separate package required.

1. Installation

OSInstallation
Kali LinuxUse Firefox/Chromium on Kali — press F12. No separate package required.
All browsersPress F12 or Ctrl+Shift+I

2. Basic commands

  1. 1. See every request a page makes

    Network tab → reload

    See every request a page makes

  2. 2. Inspect cookie flags (HttpOnly, Secure)

    Application → Cookies

    Inspect cookie flags (HttpOnly, Secure)

  3. 3. Show help

    Network --help

    List flags for your installed version (same habit as man/--help).

  4. 4. Short help

    Network -h

    Alternate help flag when supported.

  5. 5. Keep requests across navigation

    Preserve log

    Keep requests across navigation

  6. 6. Force fresh requests

    Disable cache

    Force fresh requests

Options / flags

OptionPurpose
Preserve logKeep requests across navigation
Disable cacheForce fresh requests

5. Useful features

  • Network tab
  • Storage/Application tab
  • Console
  • Sources & debugging

6. Practical examples

  1. Example 1: See every request a page makes

    Network tab → reload

    See every request a page makes

  2. Example 2: Inspect cookie flags (HttpOnly, Secure)

    Application → Cookies

    Inspect cookie flags (HttpOnly, Secure)

  3. Example 3: Show help

    Network --help

    List flags for your installed version (same habit as man/--help).

  4. Example 4: Short help

    Network -h

    Alternate help flag when supported.

  5. Example 5: Keep requests across navigation

    Preserve log

    Keep requests across navigation

7. Important notes

  • Used by every web developer; the first tool for understanding web behavior.
  • Authorized targets only — labs, systems you own, or written permission.
  • Prefer reading --help / man / official docs for your installed version; flags change over time.

Related course: web application security · bug bounty hunting · Commands: /commands#burp