Nobuf JavaScript Playground

What it does

Draft storage

A versioned draft is stored only in the current browser.checked 5 Oct 2026

Editors

It provides syntax-highlighted HTML, CSS, and JavaScript editors with preserved cursor position and undo history.checked 5 Oct 2026

Integrations

The playground page describes HTML, CSS, and JavaScript editing, project import, and standalone HTML download, but does not name external integrations.checked 5 Oct 2026

Isolation

User code runs in a sandboxed iframe without same-origin or top-navigation permission, and messages are accepted only from the current iframe with matching random channel and run identifiers.checked 5 Oct 2026

Local processing

The playground runs in the browser, and Nobuf says it does not receive, store, or inspect user input.checked 5 Oct 2026

Preview and logs

Users can preview DOM output and inspect logs, warnings, runtime errors, and rejected promises without executing code in the parent page.checked 5 Oct 2026

Privacy

Nobuf says tool inputs and selected files are handled on-device and are not sent to an application server.checked 5 Oct 2026

Purpose

The JavaScript & HTML Playground lets users write HTML, CSS, and JavaScript with a sandboxed preview and captured console.checked 5 Oct 2026

Runtime support

The playground runs browser JavaScript rather than Node.js; ES Modules and import maps work, while Node built-ins, require, process, and bare npm imports are unavailable unless mapped to a browser-compatible URL.checked 5 Oct 2026

Saving and export

Users can keep a versioned local draft, import a project, or download a standalone HTML file.checked 5 Oct 2026

Site infrastructure

Nobuf says the site has no application API or account server and includes no third-party analytics.checked 5 Oct 2026

Stop behavior

Stop replaces the sandbox and invalidates old messages, but the page says browser scheduling prevents guaranteeing recovery from every synchronous infinite loop.checked 5 Oct 2026