No setup · no account

From a what if to a running page.

CodeRush is a creative coding studio in your browser. Give it a complete page, a React component, a Markdown note or raw data: it works out the format, transforms only when it has to, and shows the result beside the source.

Open an empty pad Run a working example

01 · Quick start

The whole loop in three moves

1
Paste or choose
Paste source into the editor and it runs right away in the sandbox. For something known-good, open one of the 12 templates, or one of the 32 demos — twenty three.js scenes and twelve games, each a whole page.
2
Inspect and adjust
Use Split for source and result together, Files to separate HTML, CSS and JavaScript, Problems to check syntax and accessibility without running code, Devices for responsive checks, Console for logs and errors, and Find for source navigation.
3
Keep it, or leave the door open
Name a local snapshot, download the source, or create a Rush link so someone else can carry it on. A Rush carries the source after the URL’s #; CodeRush stores no server copy.

02 · Formats

One pad, nine useful shapes

HTML

Complete pages or fragments

Runs as a sandboxed document with its own styles and scripts.

JavaScript

Scripts without boilerplate

Runs in a generated document, the same way a complete page does.

Markdown

Notes and documentation

Renders as a readable article. The Markdown compiler loads only when needed.

JSX / TSX

React components

Compiles in this tab with vendored Babel and React, then mounts the last component.

SVG

Vector artwork

Centers the graphic on a checkerboard stage for quick inspection.

XML

Structured documents

Shows an indented, syntax-coloured source view instead of executing it.

CSS

Style experiments

Applies the stylesheet to a small page of representative elements.

JSON

Data inspection

Pretty-prints the structure in a collapsible, syntax-coloured viewer.

Auto

No format menu required

The detector explains what it found; the source badge always shows the chosen kind.

03 · Recovery

Untrusted code gets an exit.

The preview is a sandboxed iframe with no same-origin access to the pad: code inside it cannot read this page, its storage or its cookies. Turn on Review code before it runs from the command palette and pages with JavaScript or outside connections wait for your approval first. If a render stalls, CodeRush keeps your source, turns Live off, and offers an offline retry.

Open in Safe Mode Read the exact boundary

Shift+Ctrl/⌘+.Stop replaces the active preview and ends its timers and requests.
OfflineRun offline keeps HTML and inline CSS visible without scripts, forms, popups or network requests.
>_Console captures logs, warnings, errors and source locations. Its command line inspects the current preview, awaits promises and recalls commands with the arrow keys.

04 · Continuity

Choose what leaves the tab.

Local

Files, Problems and snapshots

Files separates index.html, style.css and script.js locally, then combines one portable HTML page for preview and sharing. Problems checks syntax, duplicate IDs and common accessible-name gaps locally without executing source. Name, pin, rename, export or erase up to 24 local snapshots. Restoring first checkpoints an unsaved draft and offers Undo.

Link

Rush sharing

Public, private and password-protected modes put the source in the URL fragment. There is no server file and therefore no remote revoke button.

Opt-in

AI editing

Your prompt and current source go directly to the provider you select only after you press Send. CodeRush is not a proxy in that request.

05 · Other surfaces

The same renderer, closer to the work

Browser

Run code blocks on sites you choose

Load the Chrome extension, enable Page buttons for the named site, then use a code block’s Run button. Installation asks for no blanket website access. Its runner can show reviewed HTML and inline CSS offline before you allow JavaScript or connections. The selection context menu works without a site grant, and Alt+R opens the full pad.

Extension setup on GitHub

For agents

Give an agent the picture and the facts

A screenshot lets a model say a page looks wrong. One check adds what it cannot see: errors, failed requests, overflow, cut-off or faint text, small targets, each with its source line and CSS rule. MCP, command line or local HTTP.

See how the two fit together

06 · Shortcuts

Stay in the source

Ctrl/⌘+↵: Run
Shift+Ctrl/⌘+R: Run again
Ctrl/⌘+F: Find
Shift+Ctrl/⌘+F: Replace
Ctrl/⌘+K: Commands
?: Every shortcut

Try an idea. See what happens.

Start with a working page, then take it somewhere else.

Run the landing page Run a three.js scene