Storage Capture

The STORAGE sub-tab captures every localStorage.setItem() and sessionStorage.setItem() call in real time.

Overview

Modern web apps store data in localStorage and sessionStorage. Nothing Browser captures every write — so you can see exactly what data the app is saving.

┌─────────────────────────────────────────────────────────────────────────────┐
│  STORAGE [4]                                                               │
├──────────────┬─────────────────────┬─────────────────────┬─────────────────┤
│ Type         │ Origin              │ Key                 │ Value           │
├──────────────┼─────────────────────┼─────────────────────┼─────────────────┤
│ 🟣 localStorage │ https://example.com │ user_preferences    │ {"theme":"dark"}│
│ 🟣 localStorage │ https://example.com │ session_token       │ abc123def456... │
│ 🔵 sessionStorage│ https://example.com │ cart_items          │ [{"id":1}]      │
│ 🟣 localStorage │ https://api.cdn.com │ api_cache           │ {...}           │
└──────────────┴─────────────────────┴─────────────────────┴─────────────────┘

What Gets Captured

Column	Description
Type	localStorage (🟣 purple) or sessionStorage (🔵 blue)
Origin	Domain that set the item
Key	Storage key name
Value	Stored value (truncated in table)

Color Coding

Storage Type	Color	Persistence
localStorage	🟣 Purple	Persists until manually cleared
sessionStorage	🔵 Blue	Cleared when tab closes

Detail Panel

Click any item to see:

Field	Description
Full Value	Complete stored value (untruncated)
Key	Storage key
Origin	Full origin URL
Timestamp	When the write occurred
Size	Size of stored value in bytes

Example Detail Panel

┌─────────────────────────────────────────────────────────────────────────────┐
│  Storage Item Details                                                       │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                             │
│  Key: user_preferences                                                      │
│  Origin: https://example.com                                                │
│  Timestamp: 2026-01-15 14:30:25.123                                        │
│  Size: 156 bytes                                                            │
│                                                                             │
│  Full Value:                                                                │
│  ┌───────────────────────────────────────────────────────────────────────┐ │
│  │ {                                                                     │ │
│  │   "theme": "dark",                                                    │ │
│  │   "language": "en-US",                                                │ │
│  │   "notifications": true,                                              │ │
│  │   "fontSize": 16,                                                     │ │
│  │   "sidebarCollapsed": false                                           │ │
│  │ }                                                                     │ │
│  └───────────────────────────────────────────────────────────────────────┘ │
│                                                                             │
└─────────────────────────────────────────────────────────────────────────────┘

localStorage vs sessionStorage

Feature	localStorage	sessionStorage
Color	🟣 Purple	🔵 Blue
Persistence	Forever (until cleared)	Until tab closes
Scope	Across all tabs/windows	Same tab only
Use case	User preferences, auth tokens	Cart, form data, temp state
Clear on browser close	No	Yes

Common Uses

Type	Typical Data
localStorage	User settings, theme preferences, saved logins, API cache
sessionStorage	Shopping cart, form progress, page state, CSRF tokens

Real-Time Capture

Storage writes are captured the moment they happen:

javascript

// When a website runs this:
localStorage.setItem('user_preferences', JSON.stringify({ theme: 'dark' }));

// It appears instantly in the STORAGE tab:
// 🟣 localStorage | https://example.com | user_preferences | {"theme":"dark"}

What Triggers Capture

Action	Captured?
`localStorage.setItem()`	✅ Yes
`sessionStorage.setItem()`	✅ Yes
`localStorage.removeItem()`	❌ No (deletion not shown)
`localStorage.clear()`	❌ No (clearing not shown)
Reading values	❌ No (only writes)

How Capture Works

The capture uses JavaScript injection to patch the storage methods:

javascript

// Patched localStorage.setItem
const originalSetItem = localStorage.setItem;
localStorage.setItem = function(key, value) {
    // Capture the write
    window.__captureStorage('localStorage', window.location.origin, key, value);
    
    // Call original
    return originalSetItem.call(this, key, value);
};

This runs at DocumentCreation — before any page JavaScript — so no writes are missed.

Real-World Use Cases

1. Understanding App State

text

1. Use the web app
2. Watch STORAGE tab
3. See what data the app saves
4. Understand how it tracks users

2. Reverse Engineering Authentication

text

1. Log into site
2. Check STORAGE tab
3. Look for auth tokens in localStorage
4. Find token key name (e.g., 'access_token')
5. Use in your scraper

3. Debugging Cart Issues

text

1. Add items to cart
2. Check STORAGE tab
3. See cart data in sessionStorage
4. Verify items are stored correctly
5. Debug missing items

4. Preference Extraction

text

1. Configure app settings
2. Check STORAGE tab
3. See preference keys and values
4. Replicate in automation

5. Cache Analysis

text

1. Use API-heavy app
2. Check STORAGE tab
3. See API responses cached in localStorage
4. Understand caching strategy

Filtering Storage Items

Filter by Type

Filter	Result
Click 🟣	Show only localStorage
Click 🔵	Show only sessionStorage

Filter by Origin

Use the filter bar to search by origin:

Example	Matches
`example.com`	All items from example.com
`api.`	All items from API subdomains
`localhost`	Local development items

Filter by Key

Search for specific keys:

Example	Matches
`token`	Keys containing "token"
`pref`	Keys containing "pref"
`cart`	Keys containing "cart"

Copying Storage Data

Copy Single Item

Select item → COPY → Copies key and value

Copy All as JSON

Click COPY ALL JSON:

json

{
  "localStorage": {
    "user_preferences": "{\"theme\":\"dark\"}",
    "session_token": "abc123def456"
  },
  "sessionStorage": {
    "cart_items": "[{\"id\":1,\"qty\":2}]"
  }
}

Export for Scraping

Use the JSON output in your scraper:

python

# Python example
import json

with open('storage.json', 'r') as f:
    storage = json.load(f)
    
# Use localStorage values
token = storage['localStorage']['session_token']

Clearing Storage

Clear Single Item

Select item → Click DELETE

Clear All Captured

Click CLEAR ALL button (clears only captured data, not actual storage)

Clear Actual Storage (in Browser)

To actually clear website's storage:

Go to BROWSER tab
Open DevTools (F12) → Application → Storage
Clear manually

Privacy Note

Storage data captured in DEVTOOLS is:

✅ Stored only in memory
✅ Cleared when you click CLEAR
✅ Not saved to disk (unless you export)
✅ Wiped when browser closes (sessionStorage naturally, localStorage persists)

Troubleshooting

No Storage Items Appearing

Solutions:

Check website actually uses storage
Interact with the site (storage writes happen on actions)
Refresh the page
Check DEVTOOLS is open

Value Truncated

Solution: Click the item to see full value in detail panel

Large Values Not Showing

Solution: Very large values (>1MB) may be truncated. Use DOWNLOAD to save raw.

Storage Items Disappearing

Solutions:

sessionStorage clears when tab closes
Website may be removing items
Check if you cleared capture

Storage vs Cookies

Aspect	Storage	Cookies
Size limit	~5-10MB	~4KB
Sent to server	No	Yes (automatically)
JavaScript access	Yes	Yes (unless HttpOnly)
Persistence	Manual or session	Expiry-based
Best for	App state, preferences	Authentication, tracking

Use STORAGE tab for app data, COOKIES tab for auth tokens.

Keyboard Shortcuts

Shortcut	Action
`Ctrl+F`	Focus filter bar
`Delete`	Delete selected item
`Ctrl+A`	Select all items
`Ctrl+C`	Copy selected item

Next Steps

Cookie Inspector — Track authentication cookies
Network Inspector — See how storage data is used
DEVTOOLS Tab — Complete capture overview

Nothing Ecosystem · Ernest Tech House · Kenya · 2026

Storage Capture ​

Overview ​

What Gets Captured ​

Color Coding ​

Detail Panel ​

Example Detail Panel ​

localStorage vs sessionStorage ​

Common Uses ​

Real-Time Capture ​

What Triggers Capture ​

How Capture Works ​

Real-World Use Cases ​

1. Understanding App State ​

2. Reverse Engineering Authentication ​

3. Debugging Cart Issues ​

4. Preference Extraction ​

5. Cache Analysis ​

Filtering Storage Items ​

Filter by Type ​

Filter by Origin ​

Filter by Key ​

Copying Storage Data ​

Copy Single Item ​

Copy All as JSON ​

Export for Scraping ​

Clearing Storage ​

Clear Single Item ​

Clear All Captured ​

Clear Actual Storage (in Browser) ​

Privacy Note ​

Troubleshooting ​

No Storage Items Appearing ​

Value Truncated ​

Large Values Not Showing ​

Storage Items Disappearing ​

Storage vs Cookies ​

Keyboard Shortcuts ​

Next Steps ​

Storage Capture

Overview

What Gets Captured

Color Coding

Detail Panel

Example Detail Panel

localStorage vs sessionStorage

Common Uses

Real-Time Capture

What Triggers Capture

How Capture Works

Real-World Use Cases

1. Understanding App State

2. Reverse Engineering Authentication

3. Debugging Cart Issues

4. Preference Extraction

5. Cache Analysis

Filtering Storage Items

Filter by Type

Filter by Origin

Filter by Key

Copying Storage Data

Copy Single Item

Copy All as JSON

Export for Scraping

Clearing Storage

Clear Single Item

Clear All Captured

Clear Actual Storage (in Browser)

Privacy Note

Troubleshooting

No Storage Items Appearing

Value Truncated

Large Values Not Showing

Storage Items Disappearing

Storage vs Cookies

Keyboard Shortcuts

Next Steps