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Overview

Source maps (.js.map) map minified/bundled JavaScript back to original source code. When exposed in production, they reveal the full unminified codebase — variable names, comments, API endpoints, hardcoded secrets, and internal logic.

Finding Source Maps

Check HTTP Headers

Look for:

Direct Access

Common Paths

Enumerate with Wordlist

Browser DevTools

  1. Open DevTools → Sources tab
  2. If source maps load, original source tree is visible
  3. Check Network tab for .map requests

Extracting Source Code

unwebpack-sourcemap

Reconstructs full directory tree with original source files.

smap

source-map-cli (Node)

Manual with jq


What to Look For

API Keys & Secrets

API Endpoints

Hidden Routes & Admin Panels

Comments with Sensitive Info

Internal Hostnames & IPs


Frameworks & Common Locations


Automation — Full Pipeline


Quick Reference


Sources