Z

HTML Playground

Live HTML / CSS / JS playground with sandboxed iframe preview. Auto-saves to localStorage. Pure client-side.

Free No signup Client-side Privacy friendly

Preview auto-updates 300ms after typing.

Preview

How to use

  1. 1 Edit any pane — HTML, CSS or JS. The preview updates 300ms after you stop typing.
  2. 2 Save snippet to keep your work in localStorage for next visit.
  3. 3 Reset to load the sample again.

Why use this tool

  • Three editor panes — HTML, CSS, JS — wired into a single live iframe.
  • Snippet persistence via localStorage — close the tab, come back, your code is still there.
  • Sandboxed iframe (allow-scripts only) — JS runs but cannot reach your tools origin.
  • Pure client-side — no server round-trip on every keystroke.

Frequently asked questions

Can I import external libraries?

Yes — add <code class="font-mono text-xs">&lt;script src="https://…"&gt;</code> tags inside the HTML pane. The iframe loads them on next preview rebuild.

Is the iframe sandboxed?

Yes — we set <code class="font-mono text-xs">sandbox="allow-scripts"</code> and intentionally omit <code class="font-mono text-xs">allow-same-origin</code>, so the preview cannot read this page or its storage.

Where is my work stored?

Only in your browser's <code class="font-mono text-xs">localStorage</code> when you click Save. Nothing is sent to a server.

Summary

HTML Playground is a free developer utility by Zerethon Tools. Live HTML / CSS / JS playground with sandboxed iframe preview. Auto-saves to localStorage. Pure client-side. Runs entirely in the browser — no signup, no upload.

Category
Developer
Pricing
Free
Privacy
Browser-based
Signup
Not required

Privacy

Your data never leaves your browser unless explicitly stated. HTML Playground runs entirely client-side — no server upload, no logging, no tracking of your input.

Related tools

JSON Formatter

Format, validate, and minify JSON online. Free, no signup — your data never leaves your browser.

Open tool

SQL Formatter

Format SQL queries online — beautify MySQL, PostgreSQL, SQLite, SQL Server, Oracle, and BigQuery.

Open tool

UUID Generator

Generate UUIDs online — v1, v4, v7, and Nil. Bulk generation up to 10,000. Free, no signup.

Open tool

Password Generator

Generate strong, cryptographically random passwords. Configurable length and character sets — runs in your browser.

Open tool

Build, share, and grow on Zerethon Social

Free signup. Earn points, collect achievements, and connect with creators worldwide.

Sign up free