Your films. Your machine. Watched anywhere.
KOS is a private media server. Keep your movies, series and music on hardware you own, and watch them from the couch, the road, or a friend’s place — without handing your library or your viewing history to anyone.
macOS (Apple Silicon) app at launch · iPhone, iPad and Apple TV during the beta · node on Linux or a Mac
You already have the files.
Discs you ripped over the years. Home videos. Series you bought and downloaded. A library that took a decade to build and now lives on a drive, waiting for something better than a folder.
- Nothing to upload. Your files stay where they are. KOS indexes them in place and streams them from there.
- Coming from Plex? One command imports your matches, watch state, ratings, collections and artwork, joined by file path so nothing is guessed.
- Nothing to browse but your own. No storefront, no “Discover”, no ads, no rows of things you do not own. The whole interface is your library.
Three parts. Two of them are yours.
Understanding KOS takes about two minutes, and it is worth the two minutes, because it explains everything else on this page.
The node
A machine that stays on — a Mac Mini, a NAS, an old laptop or desktop — running the KOS node. It holds your files, your metadata and artwork, and every person’s watch history. It is the only place your media ever lives.
The client
The app you watch in. It holds almost nothing: a credential and a cache. Start a film on the laptop, finish it on the TV; everything you did is remembered on the node, per person.
The global
The one part you never install. It keeps accounts, provides metadata on request, holds the list of nodes you may use, and introduces your client to your node. It never sees your media.
In one sentence: you log in to the global; it tells your client which nodes you may use and hands both sides the info to talk to each other; then your media goes straight from your node to your screen without passing through us.
Reach your node from wherever you are.
KOS tries the direct routes first and tells you which one it took, before anything is streamed.
- Direct. Forward one UDP port on your router and every connection is your client talking straight to your node. Fastest, and free.
- Hole punch. No port forwarded? The global introduces the two ends and they open the connection to each other. Still direct, still free.
- Relay, as a last resort. When neither works, a Metakine relay copies the encrypted bytes through — without a key, so it cannot read them. Relay traffic is the one thing metered (see pricing).
- Offline. Download a film to the device for the flight, resumable.
A media server, not a media service.
Movies, series and music
Scans your folders, matches titles, fetches artwork and descriptions. Series grouped by season, albums by artist, editions and versions kept apart.
A wall that opens instantly
Browse a hundred-thousand-title library in under a second. Sort by anything, filter by genre, decade, people, resolution, audio language, watched or not — and search as you type.
Playback that respects the file
Original quality whenever the device can play it, transcoding only when it must. Subtitles, alternate audio tracks, chapters, and resume across devices.
Share with people you choose
Invite by email, set a role, revoke any time. Everyone you invite gets their own watch history, resume points and ratings on your node, and pays nothing.
Your metadata, your rules
Fix a wrong match once and lock it so no rescan undoes it. Edit any field. Add your own fields. Mark editions. Keep a film that is temporarily missing from the disk.
Run it your way
Configure the node from the app or the command line: folders, scan schedules, transcoding limits, who has access. Export everything as a bundle you can restore anywhere.
One machine that stays on, and something to watch on.
For the node
| Runs on | Linux x86-64 (Docker image recommended) or a Mac with Apple Silicon |
|---|---|
| Hardware | A NAS, a Mac Mini, an old laptop, a rented VPS. Serving a film costs almost no CPU; CPU matters only when a device needs a transcode. |
| Disk | Your media, plus a few hundred MB for KOS’s own database and artwork. |
| Network | Wired if you can. A forwarded UDP port makes every connection direct and free; without one KOS punches through, or falls back to the relay. |
For watching
| Mac | macOS 12 or newer on Apple Silicon at launch |
|---|---|
| iPhone, iPad | Through TestFlight during the beta |
| Apple TV | Through TestFlight during the beta |
| Command line | Every platform the node runs on; scriptable at launch |
| Not in the beta | Windows, Android, web browsers |
Two things cost money, and nothing else.
The beta is paid. It is the real product with real support, not a demo — and you are buying the thing itself, not credits, not a tier.
One node, served for one year, for as many people as you invite. Renews automatically; cancel any time and it serves to the end of the paid year. Unpaid, a node keeps serving its owner, with limits.
Only for traffic that had to go through our relay because no direct route existed. Most people never need one. Metadata is always free; a heavy household streaming everything relayed uses about 500 GB a year.
| Clients | Free, always. A node you have merely been invited to costs you nothing. |
|---|---|
| Currency | CAD in Canada (GST/QST added), EUR in the European Union (VAT added), USD elsewhere. Fixed by country so tax is charged and reported in one currency. |
| Payment | By card, on Stripe’s payment page. KOS never sees your card. |
By invitation, in small waves.
We open the door to a few people at a time so every problem gets looked at. Leave your address and we will send one email when your wave opens — nothing else.
Asked before you asked.
Is this a streaming service? Where does the content come from?
From you. KOS plays the files you already have on your own machine. There is no catalogue to browse, nothing to rent, nothing to subscribe to except the node itself. If you do not own it, it is not there.
Do I need a static IP or a forwarded port?
No. A forwarded UDP port makes every connection direct and free, so it is worth the ten minutes; the manual walks you through it router by router. Without one, KOS punches a hole through most home routers, and when even that fails it falls back to the metered relay — and tells you so at connect time, before streaming a byte.
Can I bring my Plex library across?
Yes. One command reads a running Plex server and imports its matches, watch state, ratings, collections and artwork choices into KOS, joined by file path — so nothing is guessed. Re-running it is safe; only differences are written. Movies, TV and music are covered.
Which file formats play?
Anything ffmpeg can read, which is nearly everything. KOS streams the original whenever the device can play it and transcodes only when it must — that is where a node’s CPU matters, and the manual explains how to avoid it.
Can Metakine see what I have or what I watch?
No. Your library, artwork and history live on your node. The global sees accounts and which nodes you may use. On a relayed connection the relay sees that two endpoints exchanged some number of encrypted bytes, and nothing about what they were.
Why is a beta paid?
Because the money is the product, in the plain sense: a $25 node-year and $10 relay packs are the whole business model, and we would rather learn whether that works with real customers than with people who were comped. You get the real thing, real support, and a say in what gets built next.
Can my family and friends use my node?
Yes. Invite them by email, give them a role, and they see your node in their app with their own history and resume points. They pay nothing. You can revoke or ban anyone at any time.
Is it Mac only?
The node runs on Linux (x86-64, Docker recommended) or on a Mac with Apple Silicon. The app is Mac-only at launch, with iPhone, iPad and Apple TV arriving through TestFlight during the beta. Windows, Android and web browsers are not part of the beta.
What happens to my data if I stop paying?
Nothing is taken from you. The node keeps serving its owner with limits, your files never moved, and everything KOS knows about them lives in a folder on your machine that you can back up or export at any time.