Domainless Code — free browser code editor

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HTML
CSS
JS
SRC
live preview
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What is Domainless Code?

Domainless Code is a free code editor that runs entirely in your browser: write HTML, CSS, and JavaScript side by side with a live preview that updates as you type.

Beyond web pens, it has firmware and scripting modes: asm (BIOS) assembles 16-bit x86 with NASM and boots your boot sector in an in-browser emulator; C (UEFI) compiles a UEFI application with the GNU-EFI toolchain into a real .efi you can inspect and download; and Lua runs in your browser and renders to the page.

Pens can be public, unlisted, or private; you can fork other people's pens, export your work, add head HTML and curated version-pinned libraries, and browse trending or starter pens to begin from.

Frequently asked questions

Is Domainless Code free?

Yes — it's a free browser code editor. Open it and start typing; your work runs instantly in the live preview.

What can I build with it?

Anything HTML, CSS, and JavaScript can do. Each pen has three editors, a console, a security scan, and settings for head HTML and external libraries (curated and version-pinned).

Can I write assembly, C, or Lua?

Yes. Pick a mode in the editor: asm (BIOS) assembles 16-bit x86 with NASM and boots your boot sector in an in-browser emulator; C (UEFI) compiles a UEFI application with the GNU-EFI toolchain into a downloadable .efi; and Lua runs in your browser and renders to the page. HTML, CSS, and JS web pens work exactly as before.

Can I share or embed my pens?

Yes — pens can be shared by link with public, unlisted, or private visibility, and embedded in your own site.