Platform support · HTML Clay docs

This page records where HTML Clay runs today, what differs between the three operating systems, and the limits the app does not try to cross.

Current platform support#

	macOS	Windows	Linux
Download	Universal DMG for Apple Silicon and Intel	64 bit ZIP, signed executable	x86_64 and ARM64 archives
Signing	Signed and notarized	Signed executable	Unsigned
File setup	Registered by the app bundle	File associations register automatically when the app launches	Install script adds MIME entry
Permissions	Native dialog with three choices	Beta dialog, fails closed	Beta, requires zenity or kdialog
Folder trust	Pinned to folder identity	Pinned to path only	Pinned to folder identity
Save durability	Full, directory flush included	Almost complete: skips the final folder flush	Full, directory flush included
Startup	Optional login item, tray only	Optional per user Run item	Optional XDG autostart entry

The Windows and Linux permission prompts have not yet been exercised on real machines, and both fail closed. On Linux, a missing dialog tool causes the request to be denied. Windows does not yet detect when a folder is replaced at the same path.

For developers#

Your scripts can reach the file too. The same local address that makes editing feel ordinary gives your scripts two narrow ways in. A program can edit the file or read it as JSON. The source is public under a source available license, and this version converts to plain MIT in February 2028.

Limits and non-goals#

State these plainly rather than discovering them.

Not a web server and not a host. Nothing is exposed off the machine. The server binds 127.0.0.1 only. If you want the same file online, that is what https://hyperclay.com is for.
Not cloud storage, an account system, or a deployment service.
Not multiplayer. Live sync is between tabs and windows on one machine, not between computers.
Not a general filesystem API. A page saves through its own token and reads only inside approved roots.
It does not make arbitrary HTML editable. Renaming a file changes which app opens it. The editor, the persistence rules and the save behavior all come from page code such as ClayJS.
Nothing outside your home folder opens at all, and dotfiles, dot-directories, HTML Clay’s own settings, and its version history are always refused.
No script is injected into your page. HTML Clay adds a save token, a durable id, and one cookie on the way out and strips its additions before anything reaches disk.
The save route has exactly one body shape. Plain document text. A JSON body is a 415, not a guess.
The data API sends no CORS headers, on purpose, so no other origin can read your files.
A page cannot be a wire handler, and one file has one handler at a time.
No chromeless app window. Files always open in the system default browser, in an ordinary tab.
The Windows and Linux permission prompts are beta, and fail closed when no dialog can be drawn.
Windows skips the final directory flush on save; macOS and Linux do it.
Bad fit for: anything that needs a server, a database, multiple simultaneous remote users, files larger than 50 MB per save, uploads larger than 25 MB, or files outside your home directory.