Atlas local-first
Zero Server Uploads
Launch App →

Local Filesystem Intelligence

Fast, private directory exploration and storage analysis in your browser.

Atlas is a lightweight, client-side utility that scans local directories on your computer to map disk usage, categorize file types, and find duplicate files. All computation executes locally inside your browser sandbox. No installations, no tracking, and zero files or metadata ever leave your machine.

Open Atlas → Explore Features ↓

What is Atlas?

Atlas was built to solve a simple problem: understanding what is taking up space inside your directories without needing to install bulky desktop utilities or trust cloud-based tools with sensitive folder structures.

By leveraging the modern File System Access API, Atlas interacts directly with your device's file system through explicit user permission. It reads directory structures, streams file data to compute cryptographic hashes, and compiles storage metrics without transmitting a single byte over the network.

Core Features

Designed for speed, clarity, and safety.

Recursive Directory Traversal

Scanner

Recursively crawls complex, deeply nested folder trees using asynchronous iterators. Provides live counters for files and directories scanned with instant cancellation support.

Storage Breakdown & Analysis

Analytics

Classifies storage consumption into clear categories (Documents, Code, Media, Archives, Executables) and identifies the largest space-consuming files in the selected folder.

Duplicate File Detection

SHA-256

Locates identical files by matching file sizes and generating cryptographic SHA-256 hashes in background Web Workers. Calculates potential recoverable disk space accurately.

Local Scan History

IndexedDB

Automatically persists previous scan sessions in browser-local storage. Reload previous reports, compare different folder snapshots, or wipe history whenever you want.

100% Client-Side Privacy

Offline

Runs strictly in your browser. No analytics, no telemetry, no third-party scripts, and no server backend. Works completely offline without an active internet connection.

JSON Report Export

Export

Download comprehensive scan metrics, folder path lists, file counts, and duplicate breakdowns as structured JSON files for offline documentation or automation scripts.

Read-Only & Non-Destructive

Safe

Atlas only requests read permissions. It never modifies, deletes, moves, or alters any file or directory on your computer under any circumstances.

Lightweight & Theme Support

Fast

Zero framework bloat. Fast loading, responsive layout, and built-in support for system dark mode and manual theme switching.

How It Works

  1. 1

    Select a Folder

    Click "Select Folder" or drop a folder onto the target zone. The browser prompts you to grant read-only access to that specific directory.

  2. 2

    In-Browser Scanning & Hashing

    Atlas traverses the folder entries asynchronously. Potential duplicate candidates with matching byte sizes are dispatched to Web Workers for SHA-256 verification.

  3. 3

    Inspect Insights & History

    View real-time storage breakdowns, largest files, duplicate groups, and saved history records. Export your scan data whenever needed.

Technical Specifications

Execution Model 100% Client-side JavaScript (browser sandbox)
Filesystem API W3C File System Access API (window.showDirectoryPicker) with folder drag-and-drop fallback
Duplicate Hashing Web Crypto API (SHA-256) via background Web Workers
Local Database Client-side IndexedDB for scan persistence and history
Network Activity 0 bytes sent or received; no telemetry or remote endpoints
Browser Support Full support on Chromium browsers (Chrome, Edge, Brave, Opera). Folder selection fallback on Firefox and Safari.

Ready to analyze a folder?

Atlas is free, open source, and requires no account or setup. Open the application and select a folder to begin.

Launch Atlas →