Everything you need, in order

Installing

Run the installer and that is it. KDownloader installs for your user only, so Windows does not ask for administrator rights and nothing is written to Program Files or to machine-wide registry keys.

The installer registers three things with Windows, all of which are removed again when you uninstall: the kdownloader:// link scheme, magnet links, and .torrent files. Link schemes are treated carefully — a link that arrives through kdownloader:// is always shown to you for approval first, whatever your settings say, because a link from a web page is not a download you started.

Installing a newer version over an older one keeps your settings, your queue and your history. They live in %APPDATA%\KDownloader, which the uninstaller leaves alone.

Browser extension

The extension is what turns a browser download into a KDownloader download. It passes the link along with the cookies, referer and user agent that the page used, which is the difference between a link that works and a link that gives you an HTML error page.

There is no local web server involved. The browser starts a small helper process and talks to it over native messaging, and that helper reaches the app through a pipe only your own Windows account can open. Nothing listens on a port, so no web page you visit can reach the downloader.

From the Chrome Web Store, install it and you are done. To load it unpacked from the source tree instead, the helper has to be told which extension ID may talk to it:

1. chrome://extensions → Developer mode → Load unpacked → pilih folder extension\
2. Salin ID ekstensinya
3. .\tools\register-bridge.ps1 -ExtensionId <id>
4. Muat ulang ekstensinya

One deliberate limit: a command from the extension can never choose the folder a file is saved into, and only http and https links are accepted. An extension that gets compromised should not be able to write files wherever it likes.

Activation

Open KDownloader, press Help at the top right, then Activation. Paste the key exactly as it appears in your email — the dashes are part of it, upper and lower case do not matter — and press Activate.

The key is checked once against the licence server. What comes back is a small signed file that the app keeps in your profile and can verify by itself afterwards, which is why it needs the network only this once.

Moving to another machine: activate it there too if you have a slot free, or release the old machine first from the My licence page. Three machines on the yearly licence, five on lifetime.

Free, trial and Pro

A fresh install runs fourteen days with everything unlocked. No account, no email address, no card. When those days are up, the application does not stop and nothing you downloaded is touched — it drops to the free limits.

Resume, the browser extension, categories, the speed limiter, the proxy settings and both themes are in the free version and stay there.

Working offline

After activation the app carries its own signed licence file, so a licence check never stands between you and a download. It refreshes that file in the background every couple of weeks when you happen to be online, and it keeps working for up to sixty days without any contact at all.

If a machine stays offline past that, Pro features switch off until the next successful check. Nothing is deleted, no download is cancelled, and the key does not have to be typed again.

What gets sent

Three things leave your machine, and only when you ask for them:

• At activation: the licence key you typed, a device identifier, and the application version. The device identifier is a one-way hash of your Windows installation and account — it cannot be turned back into a machine name, a serial number or a user name.
• At an update check: a request for one small file listing the newest version. Nothing about you is attached.
• At purchase: your email address, so the key can be sent to you, plus whatever your payment provider needs. We never see your card number.

What is never sent: the files you download, the addresses you download them from, your download history, your settings, your cookies. The application has no analytics and no crash reporting that phones home.

ffmpeg for video

Streaming sites usually keep video and audio in separate tracks. Downloading both is KDownloader's job; joining them back into one playable file is ffmpeg's, and ffmpeg is not ours to redistribute silently inside a download manager.

winget install Gyan.FFmpeg

Or put ffmpeg.exe next to KDownloader.exe, or anywhere on your PATH. Without it, video-only and audio-only streams still download, they just arrive as two files.

When it misbehaves

The extension is installed but downloads still go to the browser

This path fails silently by its nature, so there is a log: %LOCALAPPDATA%\KDownloader\bridge.log. It records every handover attempt and the reason it failed. The usual cause is an extension ID that the helper has not been told about — re-run register-bridge.ps1 with the ID shown on the extensions page, then reload the extension.

A download refuses to resume and starts again

The file on the server changed while you were away. KDownloader compares the size, the ETag and the last-modified date before it continues, because resuming into a file that has been replaced produces a corrupt download that reports success. Starting over is the safe answer, and the reason is shown on the row.

Sixteen connections are not faster than one

Some servers cap the bandwidth per connection, in which case splitting helps a lot. Others cap it per client, in which case splitting changes nothing and sixteen connections only make you look impatient. On a local network or a loopback test, a single connection usually wins outright: there is no latency to hide, so the segmenting overhead is all you measure.

Windows SmartScreen warns about the installer

The build is not signed with a commercial certificate yet, so Windows has nothing to vouch for the publisher. Check the SHA-256 on the download page against the file you have, then choose More info and Run anyway. A signed build is on the list.

Changelog

1.0.0

First public release. Segmented downloads with work stealing, resume with validation, queue and scheduler, automatic categories, Chrome and Edge extension over native messaging, HLS and DASH video grabber with ffmpeg muxing, torrents and magnet links, light and dark themes, English and Indonesian, and the update checker.

Contact

One person answers this mailbox, usually within two working days, and within one if you have a Pro licence. Include your KDownloader version, your Windows version and what you expected to happen. If it is about a licence, the order number helps.

support@kdownloader.app