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Preview of Opal DevTools

Opal DevTools by stofu1234

Ruby/Opal REPL for Firefox DevTools - Execute Ruby code directly in your browser

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Extension Metadata

Screenshots
Basic Ruby REPL usage - Execute Ruby code directly in DevTools with puts output and array operationsAdvanced features - Navigate modules with cd/ls commands, include mixins, and use localStorage helpersCode inspection - List constants, explore class methods with ls command, and inspect validation rulesExtension settings popup - Configure Opal detection mode and auto-inject options
About this extension
Opal Browser REPL - Ruby in Your Browser DevTools

Execute Ruby code directly in your browser's developer tools! This extension adds an "Opal REPL" panel to Firefox DevTools, allowing you to run Ruby code in the context of any web page.

🔷 TRY IT NOW

Visit our playground to test the extension:
https://stofu1234.github.io/opal-vite/ja/playground.html
  1. Open the playground page
  2. Press F12 to open DevTools
  3. Click the "Opal REPL" tab
  4. Start typing Ruby code!

🔷 FEATURES

• Interactive Ruby REPL in DevTools
• Pry-like commands (ls, cd, help, history)
• Command history with arrow key navigation
• Multi-line input support (Shift+Enter)
• Auto-inject Opal runtime on any page
• Works with pages that already have Opal loaded

🔷 COMMANDS

• help - Show available commands
• ls - List methods, variables, and constants
• ls obj - List methods of a specific object
• cd obj - Change context to explore objects
• history - Show command history

🔷 SETTINGS

Click the extension icon to access settings:
• Opal Detection Mode - Only show panel when Opal is detected
• Auto-inject Opal - Automatically inject Opal runtime if not found

🔷 TIPS

• Use backticks for inline JavaScript: document.title
• Use $_ to access the last result
• Press Ctrl+L to clear the console

🔷 LIMITATIONS

This extension uses eval() to execute Ruby code. Pages with strict Content Security Policy (CSP) that block 'unsafe-eval' are not supported. Use our playground page for the best experience.

🔷 OPEN SOURCE

GitHub: https://github.com/stofu1234/opal-browser-repl
Built with Opal - Ruby to JavaScript compiler (https://opalrb.com)

🔷 PRIVACY

This extension does not collect any personal data. All code execution happens locally in your browser.
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Permissions and data

Required permissions:

  • Extend developer tools to access your data in open tabs

Data collection:

  • The developer says this extension doesn't require data collection.
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Version
0.1.12
Size
859.48 KB
Last updated
24 days ago (Dec 27, 2025)
Related Categories
  • Web Development
License
MIT License
Version History
  • See all versions
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