HTML Clay

Simple Apps. One File.

A whole app in one local HTML file. Anyone can make one, because it's just HTML.

Download
Free. No account. Works offline.

A file you own

One file, start to finish

Email it, back it up, drop it in any folder. No account, no cloud, no app store. The file is the whole app, and it belongs to you.

Your changes stick

Jot a note, check a box, drag things around. It saves itself right back into the file. Reopen it next week and it's exactly as you left it.

Quiet and private

It runs entirely on your computer. No sign-up, no tracking, nothing leaves your machine. It even works on a plane.

How it works

Install HTML Clay

One small, free app. One time.

Double-click a file

Any .htmlclay file opens in your browser, in an ordinary tab. Same browser you already use, same shortcuts.

Just use it

Type, edit, organize. Changes go back into the same file, and most files save as you go.

It's just a web page

Rename it .html and it opens in any browser. HTML Clay only adds one thing: the ability for the page to save your edits back into the file.

What people make

Is it safe?

The page runs in your browser's sandbox. By default, it saves only into its own file. Inside a folder you explicitly trust, HTML Clay files can change other files in that folder. HTML Clay's file server does not serve files outside your home folder.

Programs require a separate approval. An approved document program runs with your account's permissions and can read or change files your account can access. Only approve programs you trust. AI editing sends the selected HTML, your request and any included context to your agent, which may contact its model provider.

The long version of everything the app does, with this boundary stated exactly, is on the features page.

Download v1.12.0

macOS Universal (Apple Silicon + Intel), signed and notarized
HTMLClay-1.12.0-universal.dmg 6fc5ebee0403ae850985cf277d447ad0360bae96ff42fec9b739c8415075c158
Windows 64-bit Intel or AMD, signed
htmlclay-windows-amd64.zip 9951b8d718601664d0d212fa7b388fcd8cc6571ade853425839cbfa2ba9ecc3f
Windows ARM64, signed
htmlclay-windows-arm64.zip c7a60c68bb9b5f1b27ecc38481e63f33f14cd0d2e4eb1032e0ca89eec6dca9e0
Linux x86_64
htmlclay-linux-amd64.tar.gz eaa59c0d7285a7a03562c194fa809340763c0bb5eb32097bb2a36bc217a3d247
Linux ARM64
htmlclay-linux-arm64.tar.gz 16a09377fca439d96417e389f6f0904d230f02188a5ca8546d0bdf86777e0a54

Opening it. On macOS, drag it into Applications. On Windows, unzip it and run htmlclay.exe once: it sets up .htmlclay files for your account, with no administrator prompt. On Linux, unpack the tarball and run bash install.sh, which installs into ~/.local/bin and never asks for sudo.

One thing Linux needs. Permission prompts are real desktop dialogs, drawn by zenity or kdialog. With neither installed, a file opened from outside a folder you trust is refused rather than asked about. Folders you trust work either way.

Checking what you downloaded. Every file's SHA-256 is listed in SHA256SUMS. Hash your copy and compare it with the matching line: sha256sum <file> on Linux, shasum -a 256 <file> on macOS, certutil -hashfile <file> SHA256 on Windows.

The simplest way to make and run software.