---
title: "Chrome extension 'storage' permission: local settings vs server-side data."
description: "What does the 'storage' permission do in Chrome extensions? Understand the difference between chrome.storage.local, chrome.storage.sync, and what AI extensions store on remote servers."
canonical_url: "https://vezz.me/permissions/storage/"
type: "pseo-permissions"
category: "permissions"
topic: "Chrome Permission Audit"
intent: "Best for users checking how AI extensions store custom prompts, UI preferences, email accounts, and conversation history."
---

# Chrome extension 'storage' permission: local settings vs server-side data.

What does the 'storage' permission do in Chrome extensions? Understand the difference between chrome.storage.local, chrome.storage.sync, and what AI extensions store on remote servers.

> **Best fit:** Best for users checking how AI extensions store custom prompts, UI preferences, email accounts, and conversation history.

## Technical Permission Audit

- **Manifest Key:** `storage`
- **Chrome Install Warning:** None (displays no install-time warning in Chrome)
- **Risk Level:** Lower

```json
{
  "manifest_version": 3,
  "permissions": ["storage"]
}
```

### Legitimate Uses
- Saving your custom system prompts, keyboard shortcut preferences, and panel color/opacity settings
- Persisting your preferred page-context level (`Minimal`, `Basic`, `Detailed`) across browser restarts
- Storing local conversation history threads so you can revisit recent explanations

### Red Flags to Watch For
- Storing unencrypted third-party API keys in globally readable page `localStorage` instead of isolated `chrome.storage`
- Claiming 'everything is stored locally' while silently syncing full browsing logs to an undisclosed backend

**How Vezz me handles this:** Vezz me uses `chrome.storage` to save your custom prompts, UI customization (colors, opacity, position), context settings, and email identifier locally in your browser, and supports 1-click JSON export/import of your saved prompts.

## Step-by-step workflow

1. **Understand isolated extension storage**: `chrome.storage` is isolated from webpage scripts—websites you visit cannot read what an extension saves in `chrome.storage`.
2. **Separate local settings from cloud API processing**: While UI settings and saved prompts live in `chrome.storage`, generating an AI answer requires sending your selected text and question to an AI inference API.
3. **Back up your custom prompts**: Use Vezz me's Export button to save your custom prompts as a portable `.json` file at any time.

## Why extensions use chrome.storage instead of window.localStorage

Webpages have `window.localStorage`, but extensions need their own isolated storage bucket that persists across all tabs and works inside Manifest V3 service workers.

- `chrome.storage.sync` syncs small settings (like saved prompts and theme colors) across your signed-in Chrome browsers
- `chrome.storage.local` stores larger local state on your machine
- Websites you visit cannot inspect or tamper with data stored inside `chrome.storage`

## What Vezz me stores locally vs on the server

Transparency requires separating local browser preferences from server-side account state.

- Stored locally via `chrome.storage`: custom prompts, prompt presets, panel colors/opacity/position, auto-hide timer, context level, and recent conversation history
- Stored server-side: your email address, monthly usage counter (10 free answers/month), and Stripe subscription status
- Transmitted on user trigger: selected text, your question, and enabled page context to generate the AI response

## Frequently asked questions

### Why doesn't Chrome show a warning for the storage permission?

Because `chrome.storage` only lets an extension save and read its own private settings on your device—it does not grant access to your personal files, cookies, or websites.

### Can I export the prompts Vezz me saves in storage?

Yes. Open the Vezz me extension popup, scroll to Saved Prompts, and click Export to download all your custom prompts as a standard JSON file.

## Related guides

- [Custom prompt preset library](https://vezz.me/prompts/): Browse and download JSON prompt presets for Vezz me.
- [Vezz me Privacy Policy](https://vezz.me/privacy/): Full breakdown of local storage, server retention, and AI processing.
- [Permission checker](https://vezz.me/ai-chrome-extension-permission-checker/): Compare all Chrome extension permissions.