# ProGrabDownloader

> ProGrabDownloader (https://prograbdownloader.com/) is a high-performance, 100% free cloud download manager engineered for Google Drive, Microsoft OneDrive, and SharePoint. It eliminates the frequent "failed 99% ZIP download" errors by streaming files individually with HTTP Range request resumption, automatic retry backoff, and direct-to-disk folder hierarchy preservation.

## What is ProGrabDownloader?

When users attempt to download multi-gigabyte folders from Google Drive or OneDrive using standard web browsers, the cloud provider compresses the entire directory into a single monolithic ZIP archive. If an internet hiccup occurs, standard browsers cannot resume the stream and the download crashes ("Download failed - Network error"), forcing users to start over from 0 bytes.

ProGrabDownloader solves this issue permanently by:
1. Indexing the public cloud folder structure first into an interactive file selection tree.
2. Streaming files individually straight to the client disk with zero intermediate ZIP compression.
3. Utilizing HTTP Range requests (`Range: bytes=X-`) to automatically resume interrupted transfers from the exact byte offset where the connection dropped.
4. Preserving the exact folder hierarchy (subfolders and file paths) automatically.
5. Providing multi-worker concurrency pools and speed limit throttling.

## Supported Cloud Storage Providers
- **Google Drive**: Shared folder URLs (`/drive/folders/...`) and direct file sharing links.
- **Microsoft OneDrive**: Shared folder links with "Anyone with the link can view".
- **Microsoft SharePoint**: Shared corporate and personal enterprise folders without requiring an Office 365 login.

## Key Features & Capabilities
- **Smart Byte-Level Resume**: Transfers paused or interrupted by network drops resume immediately without losing downloaded data.
- **No File Size Limit**: Capable of downloading folders of 10GB, 20GB, 50GB+, where browser ZIP generation routinely fails.
- **Interactive Directory Tree**: Preview file sizes, types, and nested subfolders; select or deselect specific files before downloading.
- **Privacy & Zero-Knowledge Architecture**: Files stream directly from Google or Microsoft servers to the user's local disk. ProGrabDownloader servers never upload, inspect, store, or proxy files.
- **Fair Use & 100% Free**:
  - Guest Visitors: 1 free cloud package download per 24 hours (no login required).
  - Free Registered Users: 10 free cloud package downloads per day with persistent cloud link bookmarks and download history.

## Documentation & Primary Links
- [ProGrabDownloader Home](https://prograbdownloader.com/): Primary cloud folder analyzer, interactive file tree viewer, and download manager.
- [Why Browser ZIP Fails vs ProGrabDownloader](https://prograbdownloader.com/#why-it-works): In-depth comparison between browser ZIP compression bottlenecks and HTTP Range streaming.
- [Frequently Asked Questions (FAQ)](https://prograbdownloader.com/#faq): Step-by-step guides for Google Drive, OneDrive, and SharePoint folder downloading.

## Legal, Compliance & Policies
- [Privacy Policy](https://prograbdownloader.com/): Comprehensive data minimization disclosures, IP rate-limiting rules, zero file storage policy, and GDPR/CCPA compliance rights. Contact: privacy@prograbdownloader.com
- [Terms & Conditions](https://prograbdownloader.com/): Terms of service, fair use allowances, and third-party trademark disclaimers (Google Drive is a trademark of Google LLC; OneDrive & SharePoint are trademarks of Microsoft Corp.).
- [DMCA & Copyright Policy](https://prograbdownloader.com/): Non-hosting service declarations and copyright takedown notice submission. Contact: dmca@prograbdownloader.com
- [Cookie Policy](https://prograbdownloader.com/): Essential session tokens, bookmark local storage, and Google AdSense partner cookie information.
- [Feature Requests & Roadmap](https://prograbdownloader.com/): User suggestions and cloud provider roadmap. Contact: features@prograbdownloader.com

## Technical Details
- **Architecture**: React 19 Frontend + Vite + Tailwind CSS + Node.js Streaming Engine.
- **Resumption Protocol**: Standard HTTP/1.1 RFC 7233 Range Requests (Status 206 Partial Content).
- **Canonical Website URL**: https://prograbdownloader.com/
- **Contact & Support**: support@prograbdownloader.com