Every download, at the speed your connection actually has.
A from-scratch C++ engine splits each file across up to 64 connections that rebalance themselves while the download runs. Files, video and torrents in one native app — with resume that survives a power cut and a private mode that fails closed.
Universal — Apple Silicon & Intel · Signed & notarized · Not an Electron app
Parallel connections per file
Protocols — HTTP, HTTPS, FTP, FTPS
Clean output file, no reassembly
Private mode, fail-closed
The engine
The interface is SwiftUI. Underneath it is dle — a C++17 download engine
built directly on libcurl, with no framework in between. It does one thing: move bytes
off a server as fast as the server will let it.
Dynamic segmentation
Naïve accelerators cut a file into equal pieces up front. When one piece is served slowly, the whole download waits for it. This engine never does that.
It starts as a single segment. Each new connection finds the largest remaining piece and splits it in half, taking the back end for itself. When a connection finishes, it adopts an abandoned segment or halves the biggest one again. The fast connections keep taking work off the slow ones, right up until the last byte.
Segments are created during the download, not before it.
Connection reuse
Every connection holds a single live handle and issues successive ranged requests over the same TCP, TLS or FTP session. No reconnecting between segments. No re-negotiating TLS. No logging in to an FTP server again and again.
When the coordinator hands half of a segment to another connection, the current one simply stops earlier at the next block boundary — the transfer is never aborted, so the connection stays warm and reusable.
Handshakes cost time. This engine pays for them once.
Resume
A small sidecar file sits next to your download and is rewritten atomically every few seconds, and again the moment you stop. It records the exact position of every segment.
When you come back, the engine re-checks that the remote file hasn't changed — comparing
size along with the ETag or Last-Modified validator — and then
picks up from the precise byte each segment reached. Not the start of a block. The byte.
When the download completes, the sidecar deletes itself.
Resume is byte-exact, not block-approximate.
More than files
Each capability runs as its own isolated subprocess, driven over a small JSON protocol. One process per download keeps the interface responsive no matter how much is running — and keeps third-party components at arm's length from the app itself.
Paste a page URL, choose a resolution, download. Audio and video are muxed with a bundled LGPL build of FFmpeg. Optionally use your browser's own session so videos you are already logged in to work — this is not a DRM or paywall bypass, and never claims to be.
Magnet links and .torrent files are handled by a dedicated libtorrent helper
process, with per-torrent detail and progress in the same window as everything else. No
second app to install.
Routes HTTP and video downloads through a bundled Tor SOCKS5 proxy, so the server sees an exit node instead of you. If the proxy drops, the download stops — it never silently falls back to a direct connection. Torrents are disabled in this mode, because BitTorrent leaks peer addresses Tor cannot hide.
Safari and Chrome extensions catch downloads, videos and torrent links and pass them to
the app through a native-messaging broker, with an mdm:// fallback. Click in
the browser, finish at full speed in the app.
Control
Cap total throughput in KB/s so a big download doesn't take the whole household's connection down with it.
Progressive downloading for metered or fair-use plans: take a full bucket, then pace to your quota per rolling hour.
Optional category folders file each download by type — Video, Audio, Documents, Apps, Compressed — as it lands.
All Downloads, Video, Audio, Documents, Apps, Compressed, Other — plus Completed and Incomplete, always one click away.
Open at login so the browser hand-off is always live, with an optional completion dialog when a download finishes.
Every engine runs as a separate subprocess. A misbehaving download can't take the app down, and GPL-licensed components stay out of the app binary.
No Electron, no bundled browser, no web view pretending to be an app. A signed Developer ID build, notarized by Apple, shipped as a universal binary for Apple Silicon and Intel and linking only system libraries. Every bundled third-party component keeps its own licence, with the full texts readable inside the app.
Specifications
ETag / Last-Modified.torrent files via a libtorrent-rasterbar helper processmdm:// fallbackQuestions
mdm:// URL
scheme as a fallback. You click in the browser; the download continues in the app at full speed.
Native, notarized, and built for macOS from the byte up.
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