Play GeForce NOW, Xbox Cloud Gaming and your own PC's Steam games on the New Nintendo 3DS.
A native, unofficial game hub with a calm, Japanese-inspired design.

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Kasumi (霞, "mist") turns the New 3DS, New 3DS XL and New 2DS XL into a little game hub with three ways to play:

• GeForce NOW: your Steam, Epic and other PC games, running on NVIDIA's servers. Cloud gaming on the 3DS, no PC needed.
• Xbox Cloud Gaming (beta): Game Pass games, and free ones like Fortnite, from Microsoft's servers.
• Steam Link: the games on your own PC, streamed over your home Wi-Fi.

The games run elsewhere; the 3DS decodes the video in hardware, plays the audio and sends your buttons back. Kasumi is not affiliated with NVIDIA, Microsoft, Valve or the OpenNOW project.

_{▶ Watch the showcase on YouTube}

A game hub. Kasumi opens on a hub where each service is a hand-painted card: misty mountains for GeForce NOW, a bamboo grove for Xbox, a moonlit hot spring for Steam Link. Press A and the card grows into that service; B brings you back. Your games sit on a shelf of covers that load around the one you're looking at, and Continue puts your last game one press away.

Steam Link. Pair once by typing a code into Steam on your PC; no NVIDIA or Microsoft account needed. Play Steam Big Picture, your desktop, your recently played games and non-Steam games you added to Steam. The right stick can drive the PC's mouse, the on-screen or phone keyboard types on the PC, up to four PCs can be paired (press Y in the Steam library), and Quit game closes the game on the PC when you leave.

Xbox Cloud Gaming (beta). Sign in with your Microsoft account from your phone and play Game Pass and free-to-play games, with your place in the queue and an estimated wait. Xbox streams every game but Fortnite in 720p; the 3DS decodes it at half size and shows a steady 30 fps.

Plays like a controller PlayStation-style layout, touch L3 / R3 / PS, and optional gyro aiming.

Readable on a small screen The top screen's 800-pixel mode, zoom, and saved zoom zones per game.

Tuned for 3DS Wi-Fi Uses both New 3DS CPU cores, smooth frame pacing and a built-in connection check.

• Works in your country (GeForce NOW): Server on Auto pings every GeForce NOW server and uses the fastest, measured again on each new Wi-Fi network. Where GeForce NOW is sold by a local partner (the GeForce NOW Alliance), pick it in Settings and sign in with that account.
• Gets you into the game (GeForce NOW): Kasumi follows your place in the queue as NVIDIA moves it between servers, offers to resume or end a game still running on your account, and when NVIDIA is still releasing your last session it counts down and tries again by itself.
• Steadier Wi-Fi while you play: StreetPass, SpotPass and other background Wi-Fi work pause during a game (like Moonlight does), so the radio stays on the stream. If a network was choppy last time, the next session there starts in Weak / hotspot mode by itself.
• Your library as a shelf of covers, saved on the SD card so it opens instantly, with All / Favourites / Recent tabs and a page for every game. Covers download in the background, the focused game first.
• Per-game options: bitrate, gyro, button layout and a fully custom button mapping just for that game.
• Queue with an estimate and an alert: the free-tier queue shows a wait time that learns from your own queues. Close the lid while you wait; when the rig is ready the notification light pulses and a chime plays.
• Picks up where you left off: Continue relaunches your last game in one press, and if Kasumi ever closes mid-game, the next start offers to resume the game still running on your rig.
• Stream menu (hold START + SELECT): screenshots, controls sheet, zoom zones, gyro, sound and disconnect.
• Remote keyboard and touchpad for launchers, sign-in screens and chat.
• Comfort: five colour themes, stream volume, session timer, and automatic reconnect, including after closing the lid, back onto the same rig.
• First-run guide that walks you through everything (skippable).
• Updates itself from GitHub, with release notes on the console; the update page opens by itself when a new version is out.

The game hub	Your games on a shelf	A game's page
Playing, with live stats	Stream menu	Zoom zones for small text
Settings	Remote keyboard	Waiting in the queue

• A New Nintendo 3DS, New 3DS XL or New 2DS XL (the original 3DS lacks the video decoder).
• Custom firmware (Luma3DS) to install homebrew.
• At least one of:
  • a GeForce NOW account, from NVIDIA or a GeForce NOW Alliance partner (the free tier works, with a queue and one-hour sessions);
  • a Microsoft account for Xbox Cloud Gaming (most games need Game Pass Ultimate; free-to-play games like Fortnite don't);
  • a Windows, Mac or Linux PC running Steam on the same Wi-Fi, for Steam Link (Remote Play on, in Steam's settings).
• 2.4 GHz Wi-Fi with a good signal (3 bars is best).

Quickest: open FBI on the 3DS, choose Remote Install > Scan QR Code, and scan the code on the right. FBI downloads and installs the latest Kasumi.cia directly.

Or download Kasumi.cia from the Releases page and install it with FBI, or copy Kasumi.3dsx to sdmc:/3ds/ and start it from the Homebrew Launcher.

After that, Kasumi updates itself: Settings > Updates shows what's new and installs the latest release in place (it checks automatically, only in the menus). Your login, library and settings are kept. Every download is checked against the release's SHA256SUMS before anything is installed.

1. Open Kasumi and follow the short guide, then pick a service on the hub. Only the service you pick asks you to sign in.
2. Press A on its card to set it up. No password is ever typed on the 3DS:
   • GeForce NOW and Xbox: open the web address shown on your phone or computer and enter the code. Most GeForce NOW accounts are NVIDIA's (the default); if you bought it from a local partner, first pick it in Settings > Account > GeForce NOW provider.
   • Steam Link: start Steam on your PC. Kasumi finds it on your Wi-Fi and shows a code; type it into the window Steam opens on the PC. If it isn't found, press X and type the PC's address instead.
3. Your games appear on the shelf. Press A on one to open it, then A again to play. B goes back to the hub, where the other services wait.
4. During play, hold START + SELECT for the stream menu.

Remote keyboard: tap keys or use the D-Pad and A. B deletes, Y is space, START is Enter, L is Shift (twice for Caps Lock), R switches symbols, ZL is Tab, X closes. Typed text is never stored or logged.

Custom mapping: open a game, press X (Options) and choose Button mapping. Press any 3DS button to pick it, then use the Circle Pad (or the arrows) to choose what it sends: any PlayStation button, trigger, stick click, D-Pad direction, or nothing. Only that game uses the mapping.

• Choppy picture? Move closer to the router, or set Bitrate to Steady 1 Mbps (Settings, or just for one game in its Options).
• Want more detail? On strong Wi-Fi (3 bars), set Bitrate to Sharp.
• Phone hotspot or far from the router? Set Settings > Network > Connection type to Weak / hotspot: a steadier, slightly softer picture that copes with mobile data.
• High ping? Settings > Network > Server on Auto picks the GeForce NOW server with the lowest ping from wherever you are; you can also pick one yourself.
• Small text? Use ZOOM and drag the map; save the spot as a zoom zone.
• Gyro: While aiming only steers while ZL is held, which suits most shooters.
• Connection check (Settings > System) measures Wi-Fi, latency and speed and suggests a bitrate.

Can you cloud game on a 3DS without a PC? Yes. With Kasumi, a New 3DS streams games straight from GeForce NOW's cloud servers. You don't need a gaming PC, only the 3DS, Wi-Fi and a GeForce NOW account.

How do I play Steam or other PC games on a 3DS? Two ways. With GeForce NOW, link your Steam, Epic, Ubisoft or other store account in GeForce NOW (on play.geforcenow.com or its app), then launch the game from Kasumi; it runs on NVIDIA's servers using the copy you own. With Steam Link, Kasumi streams the games from your own PC instead: pair it once and play anything Steam on that PC can run.

How is Kasumi different from Moonlight? Moonlight streams from your own PC through Sunshine or NVIDIA GameStream. Kasumi's Steam Link streams from your own PC through Steam itself, with nothing else to install, and its other two services need no PC at all.

A game on my PC ignores the controller (Steam Link). Some PC games only take keyboard and mouse, like Minecraft Java Edition. In Steam on the PC, turn on Steam Input for that game and pick a keyboard and mouse layout, or add a controller mod (Controlify, for Minecraft).

Kasumi can't find my PC (Steam Link). Some routers, guest networks and PC firewalls block the search. Press X on the Steam Link card (or Y, then X, once paired) and type your PC's IPv4 address: run ipconfig on the PC and look for a number like 192.168.1.20. If nothing answers there either, set the PC's network to Private in Windows' network settings, or allow Steam through Windows Firewall. On Linux, open UDP ports 27031-27036 and TCP ports 27036-27037 in the firewall (ufw, firewalld).

Do I need a paid GeForce NOW membership? No. The free tier works, with a queue before each session and a one-hour limit. Kasumi shows the queue with a wait estimate and warns you before the hour ends.

Does it work on an original 3DS or 2DS? No. Kasumi decodes video with the hardware decoder that only the "New" models have.

30 or 60 FPS, and which bitrate? GeForce NOW and Steam Link stream at 30 FPS by default; Settings > Picture > Frame rate offers 60 FPS (beta), which wants strong Wi-Fi. Xbox Cloud Gaming shows a steady 30 FPS of Xbox's 60. For GeForce NOW, Kasumi uses about 1.3 Mbps by default (Adaptive), about 1.8-2 Mbps with Sharp on strong Wi-Fi, and about 1 Mbps with Steady 1 Mbps for weak Wi-Fi or a phone hotspot.

How is the latency? It depends mostly on your distance to NVIDIA's servers and on your Wi-Fi. In testing, the network round trip was around 60-80 ms, plus one or two frames that Kasumi holds back to keep the picture smooth. It feels fine for adventure, RPG and most action games, less so for competitive shooters. The stream stats show your live ping.

Is my account safe? Should I link Steam? Kasumi signs in through NVIDIA's and Microsoft's own device-code pages on your phone or PC and never sees those passwords. It never sees your Steam password either: store accounts are linked inside GeForce NOW itself, and Steam Link pairs with your PC through the code you approve in Steam, the same way Valve's own Steam Link app does. The code is open source, so anyone can check what it does. It is an unofficial client, so, as with any third-party client, use it at your own discretion.

My game save is gone. Did Kasumi delete it? No. Kasumi never touches saves: they are kept by the game's store (Steam Cloud, Epic, Ubisoft...) or the game's own account. Leaving the stream closes the game at once, so quit from the game's own menu first to let it save and sync. Also check you launched the same store's version as before.

GeForce NOW in my country is sold by a local partner. Does it work? Yes (still new). In some countries GeForce NOW is run by a GeForce NOW Alliance partner with its own accounts and servers. Open **Settings > Account

GeForce NOW provider**, pick your partner, sign out if you were signed in, and sign in again; your library, servers and sessions then go through that partner. The list comes from NVIDIA, and players have confirmed it works with ABYA and Digevo (Chile) and Pentanet (Australia). Keep NVIDIA if your account is NVIDIA's own, even when a partner exists in your country. Partner queues can be much longer than NVIDIA's.

"This account can't stream here" or an empty library? Usually the account and the provider don't match: an NVIDIA account signed in through a partner, or a partner account signed in through NVIDIA. Change Settings > Account > GeForce NOW provider, sign out and sign in again.

"Launch failed" or a countdown before my game starts?

• Session limit (HTTP 403): NVIDIA still counts an earlier session (it can take a few minutes to release one), or GeForce NOW is open on another device. If a game is running elsewhere, Kasumi offers to resume it here or end it; otherwise it counts down and tries again by itself. Closing GeForce NOW on your other devices and browser tabs helps.
• Too many requests (HTTP 429): NVIDIA limits launch attempts after several in a row. Kasumi waits it out and tries again by itself; pressing launch over and over makes it last longer.
• "Limited mode" (HTTP 500): NVIDIA has restricted streaming on the account itself. Check whether it can play on play.geforcenow.com; if not, the account needs sorting out with NVIDIA.

Kasumi asked me to sign in again. Why? Your login is renewed in the background. If NVIDIA can't be reached at that moment (no Wi-Fi yet, a busy server), Kasumi keeps your login and just asks you to try again; you only need to sign in again when NVIDIA no longer accepts the old login.

Does it run on an emulator (Citra / Azahar)? No. Kasumi needs the New 3DS hardware video decoder and a real network connection.

What happens when I close the lid mid-game? The 3DS turns Wi-Fi off when the lid closes, so the stream stops. Kasumi keeps your game on the rig and reconnects on its own when you open the lid again.

Which games work? Any game in your GeForce NOW or Xbox Cloud Gaming library, and anything Steam on your PC can run. Kasumi shows up as a standard controller, so games with controller support work out of the box, and Steam games work too even without native controller support, because Steam Input translates the controller for them. The touchpad and keyboard are for navigating launchers, sign-in screens and chat, not for playing.

Who Kasumi talks to. Only the services you set up: NVIDIA (sign-in, your library, servers and game sessions), or your GeForce NOW partner if you picked one; Microsoft (sign-in, Xbox Cloud Gaming sessions and the Game Pass catalog); and, for Steam Link, your own PC on your home network, plus Steam's store for the names and covers of games you played. Also GitHub, to check for and download updates; and Kasumi's report service, only if you allow it (below). When a cloud game starts, the stream also asks NVIDIA's and Google's public STUN servers for your public address, as browsers do for video calls; nothing else is sent to them.

What stays on your SD card (sdmc:/3ds/kasumi/):

• gfn-session.json, xcloud-login.json and steam-link.json: your GeForce NOW login, your Microsoft login and your PC pairings. Never share these files. No password is in them (you never type one on the 3DS), but they let anyone use those accounts or stream from your PC.
• Your settings, library cache, chosen provider, a random console ID made by Kasumi, and the diagnostic logs.
• The names of Wi-Fi networks you played on, with their fastest server and whether the last session there was choppy. They are used to pick the server and Weak / hotspot mode, and are never logged or sent anywhere.

The diagnostic logs (kasumi-diagnostic.txt and kasumi-diagnostic-previous.txt) exclude tokens, passwords and anything you type, and are safe to attach to bug reports.

Sharing is opt-in. Kasumi asks once, "Help improve Kasumi?". If you choose Share, it sends:

• Problem reports: the log, on its own when something goes wrong (the previous run crashed, froze or lost power, a game failed to launch, or the stream could not reconnect), at most once per run and never during a game.
• Performance stats: after each session of 30 seconds or more, a few numbers (session length, game, server, ping, bitrate, frame rate, lost and repeated frames, reconnects, decode time), and for each launch whether the game started and why not, the provider, queue time and how long it took. Each comes with Kasumi's version and the random install ID, so one console's numbers can be grouped. No log text, no account, no addresses. Kept 90 days.

If you choose No thanks, nothing is ever sent unless you use Send diagnostic report yourself. Change either one anytime under Settings > System (Share problem reports, Share performance stats); turning stats off also deletes the ones not sent yet.

A report holds the logs of this run and the previous one, your settings.json (including the random install ID, which is not linked to your NVIDIA account), and the newest Luma crash dump of Kasumi from the last few days. Public IP addresses in the logs are shortened to their first two numbers, and your login is never included. Reports are kept for 30 days and are only readable by the developer. The service doesn't store your IP address: it only keeps a scrambled hourly counter to stop flooding, deleted after an hour. The service's code is in server/report-worker.

The easiest way: in Kasumi, open Settings > System > Send diagnostic report, then mention the code it shows (like K7F-2QX) in your bug report or in the Discord. Kasumi keeps the log of the previous run too, so this works even after a crash or freeze.

You can also attach the files yourself: sdmc:/3ds/kasumi/kasumi-diagnostic.txt (this run) and kasumi-diagnostic-previous.txt (the run before), plus, after a crash, the newest Luma dump from sdmc:/luma/dumps/arm11/. Ideas are welcome as feature requests.

Kasumi is free and always will be. If it made your 3DS feel new again, you can support its development on Ko-fi. 20% of every donation goes to charity.

Join the Kasumi Discord
_{Chat with other players, get setup help, share reports and hear about new versions first.}

The same code is in Kasumi under Settings > System > Kasumi Discord: scan it with your phone straight from the 3DS.

Install devkitPro with the 3DS packages (plus CMake):

pacman -S --needed 3ds-dev 3ds-curl 3ds-jansson 3ds-mbedtls 3ds-libopus 3ds-cmake

From devkitPro MSYS in the repository root, build the WebRTC transport once, then the app:

bash tools/build-transport.sh
make
make cia MAKEROM=/path/to/makerom BANNERTOOL=/path/to/bannertool

make produces Kasumi.3dsx; make cia needs makerom and bannertool. How the stream, pacing and input work is described in docs/TECHNICAL.md.

To publish a release, set the version in the Makefile, write docs/releases/v<version>.md, and run bash tools/make-release.sh (with MAKEROM and BANNERTOOL set); it builds the CIA, the .3dsx and SHA256SUMS and prints the gh release create command.

Kasumi builds on the open-source OpenNOW family of GeForce NOW clients, especially OpenNOW-Switch and OpenNOW-Vita, and on libpeer, libsrtp, usrsctp, mbedTLS, libcurl, jansson, libopus, stb_image, citro2d and libctru. MVD and zoom work was informed by Moonlight-N3DS, and its moonlight-common-c 3DS socket code showed how to get the largest receive buffer the 3DS allows. Voice chat's echo cancellation and microphone setup follow TriCord, the 3DS Discord client. Steam Link was written from ihslib (with Simone Caronni's pairing key exchange), NSteamLink and SteamDatabase/Protobufs; Xbox Cloud Gaming from UnknownSKL's Greenlight, xbox-xcloud-player and xal-node. Details in THIRD_PARTY.md.

Kasumi's voice is VOICEVOX:春日部つむぎ (VOICEVOX). The Home Menu jingle and sound effects are original, made with tools/audio. Menu music from Pixabay under the Pixabay Content License: "Bossa Nova Cafe Morning Breeze" by Alex Morgan (573876), "Bossa Nova Morning Music" by Andriih (599227) and "Bossa Nova or Lofi" by TheBoysBeats (296432).

GeForce NOW and NVIDIA are trademarks of NVIDIA Corporation. Xbox and Xbox Cloud Gaming are trademarks of Microsoft Corporation. Steam and Steam Link are trademarks of Valve Corporation. Nintendo 3DS is a trademark of Nintendo. Kasumi is an unofficial fan project and is not affiliated with or endorsed by any of these companies.

Kasumi is free software under the GNU General Public License v3.0: you may use, study, share and modify it, and anything you distribute that is based on it must stay under the GPL with its source available. Third-party components keep their own licences; see THIRD_PARTY.md.