v1.0 Free & open source — watch the film

One beam. Many rays.

The fast, beautiful, open-source download manager.

Prism splits every file across up to 32 connections, catches downloads and videos straight from your browser, and picks up exactly where it left off — even after a crash.

Download Prism All downloads Star on GitHub

Windows · macOS · Linux — 64-bit

  • Free & open source (MIT)
  • Windows · macOS · Linux
  • No ads, no tracking
Prism's main window: a list of downloads with live progress and speeds, and a connections pane showing 16 parallel segments for one file. Prism's main window in the light theme: a list of downloads with live progress and a connections pane with 16 segments.
Mini window: total speed and the three active downloads. Mini window in the light theme.
Download complete dialog with Open and Open folder buttons. Download complete dialog in the light theme.
15×
faster than one connection
on servers that throttle each connection (1 GiB: 16.8 s vs 256 s)
1029MiB/s
raw throughput
2 GiB from a local server in 2.0 s — no assembly step
32
connections per file
tuned automatically, with per-host limit detection
~250ms
browser click → Prism
measured 257 ms from link click to the Download window

Features

Everything a power downloader expects.
None of the baggage.

Multi-connection engine

Every connection busy until the very last byte.

Prism splits a file into segments and keeps them all moving. The moment a connection finishes, it takes over half of the largest range still left — so nothing sits idle. Servers that limit connections are detected and respected, and a stalled tail gets raced.

  • Up to 32 connections per file, with per-host memory and polite back-off.
  • Writes straight into the final file — no slow “assembling” copy at the end.
  • Crash-safe resume: data is flushed to disk before progress is saved, and checked with ETag / Last-Modified when you resume.
  • HTTP/1.1, HTTP/2, FTP/FTPS, HLS and DASH streams.
15× fasterthan a single connection when the server throttles each one
1029 MiB/son an unthrottled local link — 3.2× aria2c
Crash-safeapp killed mid-download, resumed after restart — file verified by SHA-256

Browser integration

Every click, captured.

Click a download link and Prism’s window is already there — in about a quarter of a second, with the file name, size and resume support known. Hold Alt to let the browser handle it instead.

  • Rules by file type, MIME and size decide what Prism takes.
  • Right-click: Download with Prism, or grab all links, images or videos on a page.
  • Logged-in downloads keep working — cookies go only to the app on your own computer.
  • Chrome
  • Edge
  • Brave
  • Opera
  • Vivaldi
  • Firefox
257 ms
Prism's Download File window for debian-13.1.0-amd64-DVD-1.iso: 3.7 GB, resumable, save folder and category. Prism's Download File window in the light theme.

Video downloads

Any video. Your quality.

A Download video button appears right on the player. Pick MP4 at the quality you want — up to 8K HDR — or just the MP3. Works on 1000+ sites through yt-dlp, which Prism installs, verifies and keeps up to date for you.

  • MP4
  • MKV
  • WebM
  • MP3
  • M4A
  • Opus
  • FLAC
  • Subtitles
  • Chapters
  • SponsorBlock
Download video dialog: quality list from 2160p60 HDR down to 480p, plus audio-only MP3, M4A and Opus. Download video dialog in the light theme.

Queues & scheduler

Set it, sleep, done. Each queue has its own concurrency, speed limit and schedule — and when it finishes, Prism can sleep, shut down or run a command.

Scheduler: the Night downloads queue starts at 02:00 on weekdays, two downloads at a time, then sleeps. Scheduler in the light theme.

Site grabber

Point it at a page, set rules by type and depth, and pick what to keep from everything it finds — manuals, papers, whole galleries.

Site grabber results: eight PDF and EPUB files found on docs.example.org, ready to download. Site grabber in the light theme.

Light & dark. Six accents.

Liquid glass over a calm, dense list. Follows your system theme, or pick your own. Try an accent — this page uses them too.

Settings, Appearance: theme light, dark or match system, six accent colours, liquid glass and motion options. Appearance settings in the light theme.

Private by design

No telemetry, no ads, no account. Nothing leaves your computer except the downloads you ask for.

  • Open source, MIT licensed
  • Extension talks only to the local app
  • Tools verified by SHA-256

Torrents & magnets

Open magnet: links and .torrent files right in Prism. The Debian netinst came down in under 40 seconds.

Pull the plug. Lose nothing.

Power cut, crash, reboot — Prism resumes from the last byte it safely wrote, and checks the server file hasn’t changed.

Out of the way

Tray icon, mini window, drop zone, clipboard monitor, notifications — Prism stays quiet until you need it.

The mini window showing 71.3 MB/s across 8 downloads. The mini window in the light theme.

Benchmarks

Fast where it matters.
Honest everywhere.

Prism’s engine against aria2c 1.37.0 and curl on identical downloads, every file verified by SHA-256. Average throughput, higher is better. Each panel has its own scale.

  • Prism
  • aria2c
  • curl (single connection)

A1 GiB, server throttles each connection

15× faster than curl

4 MiB/s per connection — what most CDNs and mirrors do.

  • Prism60.9 MiB/s · 16.8 s
  • aria2c61.0 MiB/s · 16.8 s
  • curl4.0 MiB/s · 256 s

B2 GiB, unthrottled localhost

3.2× aria2c

Raw efficiency: positioned writes into the final file, large buffers.

  • Prism1029 MiB/s · 2.0 s
  • aria2c324 MiB/s · 6.3 s
  • curl672 MiB/s · 3.1 s

CServer allows only 4 connections

= theoretical max

256 MiB, 2 MiB/s each, HTTP 503 beyond 4. Prism detects the limit and settles on 4.

  • Prism8.0 MiB/s · 32.1 s
  • aria2c8.0 MiB/s · 32.1 s
  • curl2.0 MiB/s · 128 s

DVery unreliable server

Only Prism finished

256 MiB with a 2% chance per chunk that a connection drops.

  • Prism37.7 MiB/s · 6.8 s
  • aria2cGave up (exit 1)
  • curlnot run

EReal internet: Debian 13.7 netinst, 756 MiB

All saturate the line

cdimage.debian.org over a ≈ 200 Mbit/s line. When the server doesn’t throttle per connection, nobody can beat the line itself.

  • Prism25.1 MiB/s · 30.1 s
  • aria2c25.2 MiB/s · 30.0 s
  • curl25.9 MiB/s · 29.2 s

Machine: Windows 11, 16 logical CPUs, 61 GB RAM, NVMe SSD, ≈ 200 Mbit/s internet. Scenarios A–D use Prism’s deterministic test server on localhost; E uses a public mirror. Measured 2026-10-15 with scripts/bench.sh — full method & raw numbers.

IDM was not measured. The trial on the test machine had expired and was not bypassed. The harness to measure it the same way is in the repo — results from a licensed copy are welcome.

Show all results as a table
Benchmark results: Prism vs aria2c vs curl
ScenarioToolTimeAverageVerified
A · 1 GiB, 4 MiB/s per connectioncurl256.06 s4.0 MiB/s✓
Aaria2c -x16 -s1616.79 s61.0 MiB/s✓
APrism, 16 conns16.82 s60.9 MiB/s✓
B · 2 GiB, unthrottled localhostcurl3.05 s671.5 MiB/s✓
Baria2c -x8 -s86.33 s323.5 MiB/s✓
BPrism, 8 conns1.99 s1029.1 MiB/s✓
C · 256 MiB, 4-connection limit, 2 MiB/s eachcurl128.05 s2.0 MiB/s✓
Caria2c -x1632.11 s8.0 MiB/s✓
CPrism, 16 conns32.14 s8.0 MiB/s✓
D · 256 MiB, 2% drop chance per chunkaria2c -x16——✘ gave up
DPrism, 16 conns6.79 s37.7 MiB/s✓
E · Debian 13.7 netinst, 756 MiBcurl29.17 s25.9 MiB/s✓
Earia2c -x1630.00 s25.2 MiB/s✓
EPrism, 16 conns30.07 s25.1 MiB/s✓

The film

Two minutes. One beam.

See Prism catch a download, split it into rays and finish while you sleep.

Watch on YouTube

Download

Free. For every desktop.

64-bit builds of the latest release, straight from GitHub. Pick a file — the one we recommend for you is highlighted.

Verify your download

Every release ships SHA256SUMS.txt. Compare it with the hash of your file:

# Windows (PowerShell)
Get-FileHash .\Prism_*_x64-setup.exe
# macOS
shasum -a 256 Prism_*.dmg
# Linux
sha256sum -c SHA256SUMS.txt --ignore-missing

Prefer to build it yourself? See BUILD.md (Windows & Linux) and BUILD_MACOS.md. All releases are on GitHub Releases.

Guide

Up and running in two minutes.

Install the app, add the browser extension, and you’re done. Pick your system below.

Part 1

Install the app

  1. Run Prism_<version>_x64-setup.exe

    It installs for your user account — no administrator rights needed. (IT admins: use the MSI for all users.)

  2. If SmartScreen appears, click More info → Run anyway

    The installer isn’t signed with a paid certificate, so Windows asks once. The source and the build pipeline are public.

  3. Prism opens with a short welcome tour

    It lives in the system tray while it works. The installer also registers the browser helper, magnet: links and .torrent files.

  4. Now add the browser extension

    Continue with Part 2 — that’s what lets Prism catch downloads.

Illustration: the one-time SmartScreen prompt.

Portable version: unzip anywhere (a USB stick works) and run prism.exe. Settings and history stay in the data folder next to it.

Part 2

Install the browser extension

Download prism-chromium.zip or prism-firefox.zip and unzip it into a folder that will stay (e.g. Documents/Prism Extension) — the browser loads it from there.

  1. Open chrome://extensions

    Type it into the address bar and press Enter.

  2. Turn on Developer mode

    The switch is at the top right.

  3. Click Load unpacked and choose the chromium folder

    The one that contains manifest.json.

  4. Pin Prism

    Click the puzzle icon in the toolbar and pin Prism.

  5. Click the Prism icon — it should say Connected

    Done. Click any download link to try it.

Numbers match the steps on the left.

Already using IDM or another download manager? Their extensions compete for the same downloads. Disable (or remove) the IDM Integration Module or similar extensions, otherwise they may grab downloads before Prism sees them.

If something’s off

Troubleshooting

Prism → Settings → Browser integration shows the status of every browser and repairs it with one click.

The popup says “Not connected”

Start Prism (it lives in the tray), then click Retry in the popup. Still failing? Prism → Settings → Browser integration → Repair, then restart the browser.

Downloads still go to the browser

Make sure Capture downloads is on in the popup, and that the file type is in Settings → File types (images aren’t captured by default). blob: downloads from some web apps can’t be handed over.

No “Download video” button

Hover the video. Check Show video button in the extension options, and reload the page after installing the extension.

“Extension ID” mismatch

You loaded a modified copy. Use the official zip — its ID is mmcdeiglkbfbicdjboocmhehodogilfl.

Flatpak or Snap browsers on Linux

Flatpak browsers can’t run native helpers — a browser limitation. Snap Firefox asks for permission once. For full integration use a browser installed from a deb or rpm package.

What does the extension send, and where?

A download’s address, the page it came from, the browser’s user agent and that site’s cookies — only to the Prism app on your own computer, through native messaging. No network, no servers, no analytics.

FAQ

Questions, answered.

Something else? Ask in Discussions or open an issue.

Is Prism really free?

Yes. Prism is open source under the MIT license — no trial, no paid tier, no ads, no account. Bundled or downloaded components (yt-dlp, ffmpeg and others) keep their own licenses.

Is it safe to install?

Every line of code is public, and release builds are produced by GitHub Actions from that source. Each release lists SHA-256 checksums so you can verify your file. Prism collects no telemetry, and its browser extension only talks to the app on your own computer.

Windows SmartScreen and macOS Gatekeeper may warn on first run simply because the builds aren’t signed with paid certificates yet — see the guide.

Does it work like IDM?

For the workflows people love IDM for — yes: dynamic multi-connection downloads, a browser “download this” window, video grabbing, categories, queues with schedules, a site grabber, a speed limiter and batch downloads. Prism is a clean-room implementation and isn’t affiliated with Internet Download Manager. We haven’t benchmarked IDM yet (see Benchmarks).

Does it work with Firefox?

Yes — the extension supports Firefox as well as Chrome, Edge, Brave, Opera, Vivaldi and Chromium. The extension isn’t signed by Mozilla, so regular Firefox keeps it until restart; Developer Edition, Nightly and ESR can keep it permanently. How to install it.

Is there a Flatpak? What about Snap browsers?

Prism ships as deb, rpm and AppImage. There’s no Flatpak yet: browser integration relies on a native helper, which a sandboxed app can’t register without extra work. Flatpak browsers can’t start native helpers at all, so for full integration use a browser from a deb/rpm package; Snap Firefox works after a one-time permission prompt.

Why does macOS say the app can’t be opened?

The macOS build isn’t notarized by Apple yet. Right-click Prism in Applications → Open → Open once. If it says the app “is damaged”, clear the quarantine flag:

xattr -dr com.apple.quarantine /Applications/Prism.app
Which sites can it download videos from?

Every site yt-dlp supports — more than a thousand, including YouTube, Vimeo, Twitch, X, Instagram, TikTok, Reddit and SoundCloud. Prism installs yt-dlp, ffmpeg and deno for you, verifies them by SHA-256 and keeps yt-dlp updated. Only download content you have the right to.

How can I help?

Star the repo and tell a friend — it genuinely helps. Bug reports, translations, docs and pull requests are all welcome; start with CONTRIBUTING.md. Have a licensed IDM? Running the benchmark harness and sharing the numbers would be great.

One beam. Many rays.

Free, open source and ready for your next big download.

Download Prism Star on GitHub