cfmlFiddle

A self-hosted CFML playground that runs multiple engines side by side.
Powered by CommandBox.

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What is this?

cfmlFiddle lets you write CFML code and run it against Adobe ColdFusion, Lucee, and BoxLang at the same time. You pick which engine versions to install, down to the patch level, and you can compare output across all of them in one view.

It runs locally on your machine through CommandBox. No login, no restricted functions, works offline.

Online tools like CFFiddle.org, TryCF.com, and Try BoxLang are handy for quick browser tests. cfmlFiddle is for when you need to pin a specific version, test something that touches the filesystem, or figure out why Lucee and Adobe CF disagree on how dateFormat handles a weird edge case.

Features

• Run code on one engine or all running engines at once
• Results displayed stacked, side by side, or tabbed
• Light and dark themes (follows your OS preference, or toggle manually)
• Interactive mode auto-detects forms and renders them in a sandboxed iframe so they can post back to themselves
• Save and load code snippets, or import directly from a GitHub Gist URL
• Session panel lists every payload you've run with timestamps - click any to reload it into the editor
• Archive All zips up old payloads and clears the session
• Per-result refresh (re-executes and updates timing) and dismiss buttons
• Server management with context menus for admin panels, docs, and project links
• Real-time status via Server-Sent Events (falls back to polling)
• Heartbeat checks all engines with TCP socket connections in ~50ms
• Keyboard accessible with focus indicators, skip link, and ARIA roles
• All frontend libraries ship locally - no CDN required

Engines included

The default configuration ships with server configs for:

Engine	Versions	Ports
Adobe ColdFusion	2016, 2021, 2023, 2025	12016, 12021, 12023, 12025
Lucee	5, 6, 7	13005, 13006, 13007
BoxLang	latest (native, Adobe compat, Lucee compat)	14000, 14001, 14002

Start whichever ones you need from the Server Management panel. Most of the time you'll only run two or three.

Getting started

You need CommandBox installed.

1. Clone or download this repo.
2. Edit config.json in the project root. At minimum, set boxExe to the path of your box executable.
3. Run the launcher:

   box task run launchCFMLFiddle
   

   It shows a menu of available engines. Pick one to start as the primary host, and it opens in your browser.
4. Start additional engines from the Server Management panel (click the status bar in the top right).
5. Write code, pick an engine (or "Run All Online"), and hit Run.

Other ways to start

Windows: double-click startCFMLFiddle.bat

Or start a specific engine directly:

box server start serverConfigFile=current-servers/server.cf2025.json

How it works

cfmlFiddle is a single-page app. One CommandBox server hosts the UI (the editor, status bar, results panel). When you click Run, it writes your code to a temp file in _payloads/, then uses cfhttp to execute that file on the target engine(s) and returns the output.

Each engine is a separate CommandBox server sharing the same www/ webroot. They all run the same Application.cfc, which handles IP allowlisting, payload token auth, and heartbeat monitoring.

The heartbeat uses a fast TCP socket check (~50ms for all engines) and can use either polling or Server-Sent Events (SSE) for real-time status updates.

Interactive mode

If your code outputs a form, cfmlFiddle auto-detects it and renders the result in an iframe. Forms can post back to themselves, so you can build multi-step scripts that process their own input. You can also force interactive mode with the checkbox.

Configuration

All settings live in config.json in the project root (above www/). The app reads it on startup; click Reinit in the UI to reload after changes.

Setting	Default	What it does
allowedIPs	127.0.0.1,::1,...	Comma-separated IP allowlist. Use * for any.
executionTimeout	0	Seconds before a script is killed. 0 = no limit. Adjustable in the UI.
serverPollInterval	30	How often the server-side heartbeat runs (seconds).
clientPollInterval	10	How often the UI polls for updates (seconds). Ignored when SSE is active.
editorTheme	monokai	Ace Editor theme name.
boxExe	box	Full path to the CommandBox executable.
useLocalAssets	true	Load JS/CSS from local assets/vendor/ instead of CDN.
useSSE	false	Use Server-Sent Events instead of polling. Faster updates, uses one persistent connection.

Server configs

Server configs live in current-servers/. Each server.*.json file defines a CommandBox server instance. Copy one to add a new engine.

Each config includes a jvm.javaHome path that points to the Java installation used by that engine. Different engines may require different Java versions (e.g. Adobe CF2016 needs Java 11, while BoxLang and CF2025 need Java 21+). If you have multiple JDKs installed, edit javaHome in each server config to match. If omitted, CommandBox uses whatever Java it was started with.

The customTagPaths and app.libDirs paths reference the CustomTags/ and JavaLibs/ directories in the project root. If you install cfmlFiddle somewhere other than the default location, update these paths in each server config.

Project structure

cfmlfiddle/
  config.json              # app configuration
  launchCFMLFiddle.cfc     # CommandBox task runner (start menu)
  forgetServers.cfc        # CommandBox task runner (cleanup)
  current-servers/         # server.json templates per engine
  www/                     # webroot (shared by all engines)
    Application.cfc        # IP gate, heartbeat, payload auth
    index.cfm              # single-page UI
    api2/                  # JSON API endpoints
    assets/                # CSS, JS, vendor libs, icons
    _payloads/             # temp files (auto-managed)
  snippets/                # loadable code samples
  archive/                 # zipped old payloads
  CustomTags/              # shared custom tags (all engines)
  JavaLibs/                # shared Java JARs (all engines)
  JSONUtil/                # JSON serialization library

Credits

Created by myCFML.com Sponsored by SunStar Media

Libraries

Library	License
Ace Editor	BSD 3-Clause
SweetAlert2	MIT
jQuery	MIT
jQuery contextMenu	MIT
JSONUtil	Apache 2.0
cf_dump	MIT

Engines

Engine	Website
Adobe ColdFusion	coldfusion.adobe.com
Lucee	lucee.org
BoxLang	boxlang.io
CommandBox	ortussolutions.com

License

MIT. See vendor subdirectories for third-party license files.