A remote terminal multiplexer for the Nintendo 3DS. Your shells run on the Mac; the console is a replica of one of them, drawn at 57×17 on the top screen with a touch keyboard on the bottom.
The handheld runs no shell and owns no terminal state. A companion daemon on the Mac owns the PTYs and one authoritative libghostty core per session, resolves every SGR sequence to concrete RGB, and sends the console rows of coloured cells. The console sends keys back. That split is what lets a handheld from 2011 sit in front of a modern terminal program — including one whose UI is mostly box drawing and CJK.
Built on PocketJS: the guest is a Solid application compiled to a native package, and the same guest code draws the mirror windows on macOS and Linux.
Mac (host/serve.ts, Node) 3DS (app/, PocketJS)
├─ node-pty one PTY per session ├─ Solid UI at 60 Hz, 57×17 cells
├─ libghostty WASM the authoritative ├─ passive replica: applies row
│ screen + scrollback │ diffs, never interprets escapes
├─ resolves SGR → 0xRRGGBB runs ├─ touch keyboard, one contact
├─ bakes glyphs the device lacks into ├─ tabs: SELECT new, L/R switch,
│ spare font slots, streams them │ long-press-and-slide to close
└─ opens one mirror window per session └─ hold ZL for Ctrl (New 3DS)
│ │
└────────── SVC WIRE (PKNT) over TCP ──────┘
UDP 8621 beacon carries the TCP port
The console is a replica, not a client. On attach it gets a full snapshot;
after that, ordered row diffs behind a gen/seq fence. A replica that misses
a sequence asks for a resync rather than guessing, so a dropped frame can never
leave the screen subtly wrong — the failure mode of a terminal that reconnects
into the middle of a stream.
Glyphs arrive at runtime. The app ships baked Latin and the full
U+2500–U+259F box and block ranges. Anything else a session prints — CJK,
⏺, ⎿ — is rasterized on the Mac into a font atlas for one of the device's
spare slots and streamed over the same wire, advances rewritten so a
double-width character lands on two columns.
One window per session on the Mac. Each is the mirror guest (mirror/)
running on the stock PocketJS desktop host, attached to the same daemon over
the same protocol as the console. It is a second replica, not a second
implementation: app/grid.tsx draws both. Typing into it goes to the same PTY.
The bottom screen is a resistive panel that reports one contact, so the keyboard is built around the phone conventions that work with a single finger: one-shot Shift and Ctrl, a layer key for symbols, and an action strip for the keys a terminal needs (Esc, Tab, ^C, arrows, paging). Keys are caps set into sockets; pressing sinks the cap and turns its light around.
Hardware buttons cover what you reach for most: A Enter, B Backspace,
X Tab, Y Space, START ^C, SELECT a new session, L/R switch
sessions, the d-pad scrolls history, and ZL held is Ctrl (ZL comes from
ir:rst, so it needs a New 3DS or a Circle Pad Pro).
- A 3DS running the Homebrew Launcher, on the same network as the Mac
- Bun and Node ≥ 23.6 (the daemon runs under Node: Bun's
node-ptyspawn helper hangs on macOS 26) - Docker, for the devkitARM half of the 3DS toolchain (fetched on first build)
- The PocketJS checkout comes with the repository as
vendor/pocketjs
git clone --recursive https://github.com/pocket-stack/pocket-term
cd pocket-term
bun run setup # vendor install, runtime links, daemon deps
bun run 3ds # → dist/3ds/pocketterm-main.3dsx
# copy it to the SD card under /3DS/ and launch it from the Homebrew Launcher
bun run daemon # the Mac side: PTYs, terminal cores, beaconThe console discovers the daemon by its UDP beacon and connects. The daemon
takes --port, --beacon-port, --name, --shell, --no-mirror and
--unicast <ip> — the last beacons directly at a console on a network that
eats broadcast.
To iterate on the app without reflashing, pair once while the console is running ftpd, then hot-push the guest package:
bun run pair --host 192.168.8.152 # once, with ftpd open on the console
bun run push --host 192.168.8.152 # rebuild + push; the app keeps running
bun run probe --host 192.168.8.152 # status, stats, tree, screenshotA change under vendor/pocketjs/hosts/3ds is native and needs bun run 3ds
plus a reflash; everything in app/ and mirror/ is a hot push.
app/ the console guest — grid, tabs, touch keyboard, replica store
mirror/ the desktop guest — the same grid, one window per session
host/ the Mac daemon — PTYs, libghostty cores, glyph baking, the wire
test/ protocol, run-building and glyph-routing tests (bun run check)
scripts/ build and device commands over the vendored PocketJS toolchain
app/protocol.ts is the contract both sides read: message shapes, the run
encoding, and which codepoints the device can already draw.
Incubating, and verified on hardware. The SVC WIRE transport it rides on lives
in PocketJS (pocket-stack/pocketjs#345);
until that lands on main, vendor/pocketjs is pinned to its branch.
MIT. PocketJS is a separate project under its own license, and libghostty
arrives through @wterm/ghostty
under its own.