Parallel Download Manager

IDM-inspired fast, verified parallel downloads for direct file links.

Replaces the browser's default download with a segmented parallel download — just like Internet Download Manager (IDM).

✨ Features

• Parallel segmented downloads — splits files into multiple chunks and downloads them simultaneously (4–8 connections based on your hardware)
• Server verification — validates every segment via Content-Range, ETag, and Last-Modified headers to ensure data integrity
• Automatic retry with backoff — failed segments retry with exponential backoff; handles HTTP 429 rate limiting gracefully
• Two save modes — Chromium showSaveFilePicker (direct to disk) or Blob fallback (memory)
• Cancel at any time — safe cancellation that discards all partial data, even at 99%
• Real-time per-connection progress — each connection gets its own progress bar showing live download status
• Dark IDM-style UI — clean, modern dark theme inspired by Internet Download Manager

🔧 How It Works

1. Click any direct file link on any website
2. Choose Normal download (browser default) or Segmented download (parallel)
3. The script probes the server for range support, splits the file, and downloads all chunks in parallel
4. Chunks are verified and assembled into the final file

📋 Requirements

• A Chromium-based browser (Chrome, Edge, Brave, etc.) or Firefox
• Tampermonkey, Violentmonkey, or Greasemonkey extension installed
• The target server must support HTTP Range requests (most do)

⚠️ Limitations

• Large files (over 512 MB) require Chromium + HTTPS. On non-Chromium browsers or non-HTTPS pages, the script falls back to in-memory assembly, which is limited to 512 MB to prevent browser crashes. Files above this size will show: "This file needs direct disk access. Use a Chromium browser on HTTPS, or choose Normal download."
• Only works on direct file links — does not work on streaming or embedded media.
• Server must support HTTP Range requests — some servers reject or ignore range headers.

🛡️ Privacy

This script does not collect, transmit, or share any data. It only downloads the file you explicitly choose to download.