How a Mac download manager actually works, and 8 you can use in 2026

Slowrox — Fri, 23 Oct 2026 14:46:09 +0000

Disclosure first: we are the Lynx team at Slowrox, and we make Lynx Download Manager, one of the eight apps compared below. Read this with that in mind. We installed and used every app here, but we did not benchmark them. Every fact about the others comes from the developer's own page, GitHub repository or Mac App Store listing, linked next to it and checked on 2026-10-23. If something is wrong or out of date, say so in the comments and we will fix it.

We start with the part we wish someone had written for us when we started: what a download manager actually does on the wire, using plain HTTP and curl. The comparison comes after.

How a download manager actually works

Every app in this post does the same core trick. Here is what happens when you hand a 4 GB file to one.

Step 1: ask the server what it supports

The client asks for the first byte and reads the answer:

curl -s -D - -o /dev/null -H "Range: bytes=0-0" -H "Accept-Encoding: identity" \
  https://example.com/big.dmg
# HTTP/2 206
# content-range: bytes 0-0/4294967296
# accept-ranges: bytes
# etag: "a1b2c3"

The number after the slash in Content-Range is the real size, so the client can plan the parts and check free disk space first.
A 206 Partial Content answer proves the server serves byte ranges. Accept-Ranges: bytes alone is only a promise.
ETag (or Last-Modified) identifies this exact version of the file. Keep it. It matters for resume.

Why not just send HEAD? Many apps do, and it usually works, but some servers block HEAD, and some report a different size for it than for the real download. A one-byte GET tells you the truth.

Why Accept-Encoding: identity? If the server compresses the response, byte ranges apply to the compressed bytes, not to the file you want on disk. Asking for no encoding keeps the ranges meaningful.

Step 2: split the file into ranges

With the size known, the client splits the file into parts and opens one connection per part, each with a Range header:

curl -s -H "Range: bytes=0-1073741823"          -o part0 https://example.com/big.dmg
curl -s -H "Range: bytes=1073741824-2147483647" -o part1 https://example.com/big.dmg

A server that honours the range answers 206 with a Content-Range header such as bytes 0-1073741823/4294967296. A good client writes each part straight into the right offset of one pre-allocated file, so there is nothing to join at the end.

Why this is faster: many servers and CDNs limit the speed of each connection, not of each client. Several connections add up until they hit your own line. Once the line is full, more connections add nothing, which is why good apps cap the count and split the largest remaining part when a connection finishes early, instead of opening dozens from the start.

Step 3: resume without corrupting the file

Resume is the same Range request, starting where you stopped. The trap is that the file on the server may have changed since. Send If-Range with the ETag you saved:

curl -s -H 'Range: bytes=3221225472-' -H 'If-Range: "a1b2c3"' \
  -o rest https://example.com/big.dmg

If the file is unchanged, the server sends 206 and only the missing bytes.
If it changed, the server ignores the range and sends 200 with the whole new file. Your client must notice that, throw away the old parts and start again, instead of stitching two different files together.
If-Range only works with a strong ETag. If the server sends a weak one (W/"a1b2c3"), send the Last-Modified date in If-Range instead.

416 Range Not Satisfiable usually means you asked past the end of the file: the download is already complete, or the file got smaller.

Servers that refuse ranges

Some servers answer a range request with 200 OK and the full body. Common reasons: no range support, dynamically generated files, or a proxy that strips the header. Signed links that expire after one use behave similarly. A careful client:

Detects the 200 (or a missing Content-Range) on the first range request.
Falls back to a single connection for that file.
Marks it as not resumable, so if it drops, the user knows it restarts from zero.

Browser-caught downloads add one more detail: the download manager has to send the same cookies, referrer and user agent the browser used, or the server may refuse it. If it still cannot fetch the link, the right move is to let the browser keep the download.

429 and 503: back off, do not hammer

429 Too Many Requests and 503 Service Unavailable mean the server wants less from you. The polite and effective response:

Respect Retry-After if the server sends it, in seconds or as a date.
Use fewer connections. Halving the count for that host and carrying on with the same partial file usually works better than retrying at full width.
Exponential back-off with jitter when there is no Retry-After: for example wait about 2, 4, 8, 16, then 30 seconds between attempts, with a little randomness so many clients do not retry in lockstep.
Give up eventually. If no new bytes arrive for several minutes, stop and tell the user in plain words, instead of retrying forever.

That is roughly what Lynx does today: on 429 or 503 it halves its connections for that download and continues from the bytes it already has, and network errors retry on a 2, 4, 8, 16, 30 second schedule. Most of the apps below handle this in some form; the details are where they differ.

Step 4: when your own line is the limit, use two

Once your line is full, more connections stop helping. But a Mac often has a second way out: an iPhone on Personal Hotspot, plugged in over USB, shows up as its own network interface. macOS still sends everything over one default route, so ordinary apps use only one of them.

You can see both paths and use each one directly:

networksetup -listallhardwareports        # find the Wi-Fi and iPhone USB interfaces (en0, en7, ...)
curl -s --interface en0 -H "Range: bytes=0-1073741823"          -o part0 https://example.com/big.dmg &
curl -s --interface en7 -H "Range: bytes=1073741824-2147483647" -o part1 https://example.com/big.dmg &
wait

Each part travels over a different line, so the two speeds add up. An app has to bind each connection to an interface itself, give the faster path more of the remaining ranges, and keep going if one path drops. This is what Lynx's Turbo Mode does. Only the download uses the phone's data; the rest of the Mac stays on its normal connection.

What a download manager cannot do

On a single line, it cannot go faster than that line, and it cannot resume a file the server will not serve in ranges. On a fast line with a server that does not limit each connection, the browser and every app here finish close together. The gains show up on big files, slow or far-away servers, connections that drop, and, with a second network path, when your own line is the bottleneck.

Eight download managers for Mac, in short

Free, files and torrents: Free Download Manager.
Free and open source, files only: AB Download Manager.
Free and open source, with torrents: Motrix.
File-hosting sites and long link lists: JDownloader 2.
Long-running Mac app with Safari and torrents: Folx.
Small, scriptable, FTP and SFTP built in: Progressive Downloader.
New and cheap, with a scheduler and Safari: BoltFox.
A native Mac app with browser catching, Turbo Mode with your iPhone and a notch view: Lynx (ours).

Side by side

All facts checked 2026-10-23. Prices in US dollars unless noted. "Not listed" means the source we checked does not mention it, not that the feature is missing.

App	Built with	Price	Mac build	Catches browser downloads	Resume	Torrents	Open source
Free Download Manager 6.35.1	Cross-platform app	Free	Apple silicon and Intel DMGs	Chrome, Firefox	Yes	Yes	Legacy release only
AB Download Manager 1.11.1	Kotlin, Compose Multiplatform	Free	Apple silicon and Intel DMGs	Chrome, Firefox	Not listed	Not listed	Yes (Apache-2.0)
Motrix 1.8.19 (2.0 in beta)	Electron	Free	Apple silicon, Intel, universal	Chrome, Edge, Firefox (2.0 beta)	Yes	Yes	Yes (MIT)
JDownloader 2	Java	Free	macOS 10.15 to 26	Chrome, Firefox, Opera (MyJDownloader)	Pause and resume	Not listed	Yes
Folx 5.34	Mac-only app	Free; PRO from $19.95	macOS 10.13 or later	Safari, Chrome, Firefox, Opera	Yes	Yes	No
Progressive Downloader 10	Mac-only app	Free from its site; $4.99 on the App Store	macOS 13 or later	All major browsers	Yes	With Plus	No
BoltFox 1.0.3	Mac App Store app	Free (capped); Pro $6.99/yr or $19.99 once	macOS 11 or later	Safari, Chrome, Edge, Firefox	Yes	Yes	No
Lynx 1.1.9 (ours)	SwiftUI, native to macOS	Free (Basic); Pro $29.99/yr, $4.99/mo or $99 once	Apple silicon only, macOS 14 or later	Chrome, Edge, Brave, Arc	Yes	No	No

Why "built with" matters on a Mac

A download manager sits open all day, so how it is built shows. Electron apps ship a copy of Chrome inside them and draw their own buttons. Java and other cross-platform toolkits draw their own windows too. They work, but they don't use the Mac's own controls, menus, text rendering or accessibility the way a native app does, and they usually use more memory for the same job.

We built Lynx in SwiftUI, Apple's own framework, so it behaves like the apps that come with your Mac: the system font and controls, Liquid Glass on macOS 26, light and dark mode, a real Settings window on ⌘, and VoiceOver labels on what you click. Judge for yourself from the screenshots below; that's a better test than anything we could write.

What each one is best for

1. Free Download Manager

The best-known free option. The Mac download page lists version 6.35.1 with separate Apple silicon and Intel DMGs, plus older builds for older macOS versions, and official Chrome and Firefox extensions. Its features page lists accelerated downloads, BitTorrent support and resuming interrupted downloads. The same page says open source applies to the legacy FDM release.

Best for: one free app for files and torrents, including on Intel Macs.
Keep in mind: saving media from web pages needs a separate add-on.
Sources: download page, features (checked 2026-10-23)

2. AB Download Manager

Free and open source (Apache-2.0), with about 18,700 stars on GitHub, written in Kotlin with Compose Multiplatform. Version 1.11.1 shipped on 2026-10-14 with Apple silicon and Intel builds. The README lists faster downloads, queues and schedulers, and browser extensions for Chrome and Firefox.

Best for: a free, open-source IDM-style manager for plain files.
Keep in mind: the README does not list torrents.
Sources: GitHub README, releases (checked 2026-10-23)

3. Motrix

Open source (MIT) and popular, with about 57,000 stars, built on Electron. It handles HTTP, FTP, BitTorrent and magnet links. The stable release is still 1.8.19 from May 2023, with Apple silicon, Intel and universal DMGs. Version 2 is in public beta (beta 52 on 2026-10-21) and adds a Manifest V3 extension for Chrome, Edge and Firefox.

Best for: free, open source, files plus torrents.
Keep in mind: browser catching comes with the 2.0 beta, so you are running a test release.
Sources: GitHub README, releases (checked 2026-10-23)

4. JDownloader 2

The long-standing power-user tool. Its site describes it as free and open source, with start, stop and pause, bandwidth limits and automatic archive extraction. Mac installers cover macOS Catalina through Tahoe, and older ones exist. Browser extensions come through MyJDownloader.

Best for: file-hosting sites and large lists of links, with lots of control.
Keep in mind: it is a Java app with many settings, not a native Mac app.
Sources: download page, MyJDownloader apps (checked 2026-10-23)

5. Folx

A Mac-only download manager and torrent client from Electronic Team. The free version splits each download into 2 threads and resumes automatically; PRO (from $19.95) goes up to 20 threads and adds scheduling and speed control. It integrates with Safari, Chrome, Firefox and Opera. Latest version 5.34, released 3 June 2026, for macOS 10.13 or later.

Best for: a long-established Mac app with Safari integration and torrents.
Keep in mind: the free tier is limited to 2 threads per download.
Source: Folx product page (checked 2026-10-23)

6. Progressive Downloader

An independent Mac app with multi-thread downloads and mirror search, a built-in FTP, SFTP and WebDAV browser, "Active Hours" scheduling, and AppleScript, Automator and Shortcuts support. Free from its site, $4.99 on the Mac App Store as "PD". The App Store lists version 10 and macOS 13 or later. Torrents come with its Plus upgrade.

Best for: a light, scriptable app if you also work with FTP or SFTP servers.
Keep in mind: the current version needs macOS 13; older ones are in its archive.
Sources: developer site, Mac App Store (checked 2026-10-23)

7. BoltFox

A young app (version 1.0.3, August 2026, macOS 11 or later) with up to 32 threads, pause and resume, torrents and magnet links, and capture from Chrome, Edge and Firefox, plus a Safari extension in the Mac app. Free is capped at 50 downloads and 10 videos a day; Pro is $6.99 a year or $19.99 once.

Best for: torrents, a scheduler and Safari capture in one low-cost app.
Keep in mind: the daily cap on free, and it is very new.
Sources: boltfox.net, Mac App Store (checked 2026-10-23)

8. Lynx Download Manager (ours)

Our app, so it goes last. Lynx is a download manager for Macs with Apple silicon, built around the IDM habit: big downloads in Chrome, Edge, Brave or Arc get handed to Lynx by its extension, and Lynx splits each file across several connections (up to 8 on the free Lynx Basic, up to 32 on Pro) and resumes after a drop.

Four things are not in the apps above:

A native Mac app: SwiftUI from the first line, so it looks and behaves like the apps that come with macOS, not like a web page in a window.
Turbo Mode: plug in your iPhone, turn on Personal Hotspot, and Lynx downloads over your Mac's connection and your iPhone's at the same time (Step 4 above), so big files arrive dramatically faster. Free for file downloads on Lynx Basic.
Lynx Notch: download progress and the link you just copied, shown in the MacBook notch.
Clip Download (Pro): downloads just the part of a long online video you need, as a file ready for your editor.

Every install gets the full Pro for 14 days, with no account and no card, then becomes Lynx Basic unless you buy Pro.

Best for: people who want a download manager that feels like part of macOS, big files on a slow line, and people who cut clips for edits.
Limits, honestly:
- Apple silicon only. No Intel build yet, and it needs macOS 14 or later.
- No torrents and no scheduler.
- No Safari or Firefox extension yet. In Safari you copy the link and Lynx offers it.
- Not open source.
- Pro costs more than most apps here.
Homepage: https://www.lynxdownloadmanager.com

How to choose

Intel Mac or older macOS? Free Download Manager, Folx or JDownloader.
Need torrents? Free Download Manager, Motrix, Folx, BoltFox, or Progressive Downloader with Plus.
Mostly Safari? Folx, BoltFox or Progressive Downloader.
Want open source? AB Download Manager or Motrix.
Want an app that feels like it came with your Mac? Native SwiftUI, Chrome, Edge, Brave or Arc on Apple silicon, Turbo Mode with your iPhone, progress in the notch: try Lynx. We wrote a longer comparison, with more detail per app, in our guide to the best download manager for Mac.

Which one do you use, and what made you pick it? We read every comment, especially the ones that tell us what Lynx gets wrong.

DEV Community: Slowrox