No install — runs entirely in the browser

WebX68k runs a WebAssembly build of the X68000 emulator px68k-libretro as-is, so there's no app to install and no browser plugin needed. Open the URL in a supported browser and the X68000 starts right there. The disks you load — and whatever the guest writes to them, such as in-game saves — are stored only inside your browser (IndexedDB) and are never sent to a server. Browser storage is cleared along with cookies when site data is deleted, so download any disk you care about to keep a copy.

Three drives at once: FDD0 / FDD1 / HDD

Just like real hardware, WebX68k can mount two FDDs and one HDD at the same time. Each drive row shows a real machine-style access lamp rather than a "disk inserted" indicator — it stays off by default and lights up only on the frames where the drive is actually read or written.

FDDs can be inserted and ejected without restarting the core (hot-swap), so you can switch floppies while the machine is running. The HDD, on the other hand, isn't something you'd hot-swap on real hardware either, so it can only be handled before boot: set one before starting and you can edit its contents from the file transfer dialog first. Once the machine has booted it becomes read-only and can no longer be swapped — reload the page to get back to the pre-boot state if you need to change the HDD. If you don't have a HDD image, the "Create blank HDD" button builds a Human68k-partitioned, FAT16-formatted 40MB image on the spot (it carries no IPL, so it's used as a data drive for Human68k booted from an FDD).

4:3 display mode, just like real hardware

WebX68k defaults to dot-for-dot (the core's native resolution at square pixels), but real X68000 hardware always fills a 4:3 monitor regardless of the active video mode. The "4:3 display" toggle in the toolbar's "..." menu (Display group) switches to that look at any time (the choice is saved). The correction is always applied by enlarging — 512x512-family modes stretch horizontally, 768x512-family modes stretch vertically. It's never done by shrinking, since that would drop the 1px-wide strokes of text-mode characters and make them unreadable.

Disk library and file transfer

Every FD/HDD image you've loaded is listed in the Disk Library, where you can boot, or delete it. Opening the same image again resumes right where you left off. When a dropped/selected/URL-loaded ZIP or LZH archive contains multiple disk images, none of them are auto-inserted — they're registered as a folder in the library for you to choose from.

The toolbar's "..." menu (Disk group) has a "File Transfer" tool that gives you an FTP-client-style two-pane UI for moving files between the host (your browser) and a disk image. Human68k's long, Shift_JIS file names are supported and display correctly, including Japanese names. ZIP/LZH archives you bring in can be extracted on the spot (writing back is limited to ASCII 8.3-format names).

Save state / load state

Two entries in the toolbar's "..." menu (State group) let you save and restore the entire running state to your browser (IndexedDB). Saved data is gzip-compressed.

What gets saved is the machine state only — CPU, memory and the various controllers — not the contents of the disk images. Restoring therefore never swaps the disks in the drives or rewinds their contents to how they were at save time: whatever is inserted at that moment keeps being used. Restoring with a different disk inserted than when you saved could make the guest misbehave, so on load WebX68k compares the drive configuration at save time against the current one and shows a confirmation dialog before restoring if they don't match.

Mouse support

Clicking the canvas (or right-double-clicking it) captures the mouse via Pointer Lock, so your host mouse movement is forwarded straight to the guest. Because of how the X68000's mouse hardware works, it can only send relative movement — the guest itself keeps track of cursor position — so the browser's absolute pointer coordinates can't be handed over directly. To work around that, WebX68k reads the IOCS work area every frame to learn the guest cursor's current position and sends only the difference from the target, forming a closed loop that tracks absolute position. The only way to release the capture is the Esc key (while captured, the cursor belongs to the guest, so the toolbar's "..." menu can't even be opened).

Virtual keyboard

px68k-libretro itself ships no on-screen keyboard, so WebX68k built its own so the X68000 can be operated on touch devices too. At PC widths, a small kana engraving is always shown in the corner of each key, like a real keycap. At phone widths there's no room for that, so it's hidden instead — the primary (alphanumeric) engraving swaps for the kana one only while kana lock is active. Latching SHIFT while kana lock is active swaps it again to the secondary engraving (ぁ ぃ っ 、 。 「 」 etc.). Modifier keys come in two flavors — one-shot (SHIFT / CTRL / OPT.1 / OPT.2) and lock (CAPS / Kana / Romaji / Code Input / Hiragana / Zenkaku) — and multiple can be latched at once. XF1–XF5 are always present, and the "Ten-key" key toggles the numeric pad cluster on and off.

Joystick (gamepad) support

Plug in a Gamepad API-compliant controller and it works right away, up to two at once as Port 1/2. Directional input supports both the D-pad and the left stick (with adjustable deadzone). The "Joystick Settings" dialog, in the toolbar's "..." menu (Input group), shows the list of connected pads, a live display of both physical input and what's reaching the X68000 side, and full binding editing (detect, combo add, remove, reset to XInput defaults). Pad type can be Default (2 buttons), CPSF-MD (8 buttons), or CPSF-SFC (8 buttons) — a change takes effect on the next boot — and pad buttons can also be mapped to X68000 keyboard keys. Settings are saved to the browser per pad.

Virtual pad (playing on a phone)

The toolbar's "Input Panel" button can show a touch virtual pad instead of the virtual keyboard (mutually exclusive). Directional input is analog-stick-style (a fixed base with a knob, snapping to 8 directions) — a light tap near the edge of the circle is enough to get a direction out. Four built-in profiles are included — Joystick (2 Buttons) / Cursor Keys + Space / Tenkey / Joystick (6 Buttons, Mega Drive layout) — and "Edit assignments…" at the end of the 🎮 menu lets you build your own. The on-screen position is chosen automatically from measured available space: a docked "Panel" below the screen in portrait, "Sides" placement in the left/right margins in landscape, or a semi-transparent "Overlay" on the screen when neither margin is big enough.

For PC users without a gamepad, a physical keyboard can also be mapped to joystick input ("Keyboard Assignment" in the "..." menu's Input group, disabled by default), picking from built-in profiles that map the arrow keys to a joystick or to the numeric keypad — or building your own by pressing "Add Key" to register new input sources.

Add to Home Screen (hides the URL bar on iPhone)

iPhone has no way for a web page to hide the browser's URL bar, so adding WebX68k to the Home Screen and launching it from there runs it without one (Android already hides it via the Fullscreen button's native fullscreen).

Confirmed: saved disks, state, and BIOS (IndexedDB) are not shared between the Home Screen app and a regular browser (Safari/Chrome) — on iOS, the Home Screen app, Safari, and Chrome each have their own independent storage (confirmed on a real device). It's best to pick one and stick with it; if you play from the Home Screen app, you also need to register disks from that same app. This is an iOS platform limitation that cannot be worked around from the app side.

AI agents can operate the X68000 directlyMCP support

Through a local MCP server (webx68k-mcp), AI agents such as Claude Code can drive WebX68k directly. The MCP server always runs on your own machine, and screen contents or disk images are never sent to an external server.

Open WebX68k with the ?bridge=1 parameter to have the page connect to your local MCP server. Some of the main tools:

Since the X68000's console is graphics-drawn, there's no way to read the screen as text — use screenshot to check it. See mcp/README.md for full setup instructions. Everything runs locally.

Bring your own ROM dumps

If you have real IPL-ROM / CGROM (font ROM) dumps from actual hardware, you can load them from the "BIOS Settings" panel. Loaded files are saved to your browser's IndexedDB, are loaded automatically from then on, and take priority over the bundled versions.

Privacy and licensing

This repository is licensed under GPLv2. The bundled IPL-ROM and Human68k system disk are not GPLv2 — they're distributed under the terms of 許諾条件.txt (redistribution unmodified and free of charge). Those terms require the document to accompany any redistribution, so it ships alongside the disk image in system/. No commercial software disk images are bundled.

Any disk image or ROM you supply and load yourself is stored only inside your own browser (IndexedDB) and is never sent to a server. You're responsible for the rights and handling of any such images you choose to load.