SnailTrail Debug bar

Simple Debug Panel for Static Sites

A lightweight debug panel for static sites built for Jekyll, Eleventy, Hugo, and other static site generators. Inspired by Laravel's debug bar, Snail Trail provides real-time performance metrics, resource analysis, and development insights—all accessible via a sleek pull-up panel.

• Performance Monitoring - TTFB, FCP, LCP, Resource Timing
• Resource Analysis - Track scripts, stylesheets, images with sizes and load times
• Environment Info - Viewport, user agent, connection type, color scheme
• JavaScript State - LocalStorage, SessionStorage, cookies, event listeners
• DOM Analysis - Node count, depth, accessibility checks (missing alt tags)
• Console Interception - Capture and display console messages within the panel
• Build Information - Display build timestamps, git hashes, environment
• Keyboard Shortcut - Toggle with Ctrl+Shift+D
• Mobile Friendly - Debug on any device without DevTools
• Customizable - Drag to resize, persistent state
• logcad intergration, catches dispatched log messages from logd
• Simple usage: localstorage variable, window __BUILD_TIMESTAMP__, __BUILD_HASH__, __BUILD_ENV__
• UI memory: Remember UI state: open, close, height

• Ctrl+Shift+D - Toggle debug panel visibility

🔘 Option 1: Direct Include auto load

1. Link script file local or from cdn:

   <!-- Add before closing </body> tag -->
   <script src="path/to/snailtrail-debugger.js"></script>
   <!-or->
   // PENDING <-------

2. Basic Usage Vanilla JS, just set the localstorage varriable __snail_debug to true;

   // In browser console or your script set `__snail_debug` to `true`
   localStorage.__snail_debug = 'true';
   // if you've linked debugger.js as standard script, it will auto run initialization automatically
   // can always set a button to do this
   // Looks for
   // - `__snail_debug` in LocalStorage
   // - `__BUILD_TIMESTAMP__`, `__BUILD_HASH__`, `__BUILD_ENV__` in window

🔘 Option 2: ES Module ( type="module" )

1. Install snail trail debugger

   npm install snailtrail-debugger # use npm
   # or via cdn: jsdelivr
   <script src="https://cdn.jsdelivr.net/npm/snailtrail-debugger@latest/dist/snailtrail.js"></script>

2. Import requred functions

   import { SnailTrailDebugger, initSnailTrailDebugger } from 'snailtrail-debugger';

3. Modern Usage with ES6 Enable the debugger:

   // In browser console or your script set `__snail_debug` to `true`
   // Initialize the debugger
   const SnailTrailDebugger = new SnailTrailDebugger({
     storageKey: '__snail_debug'
     parnelId: 'debug-panel'
     buildInfo: {
       timestamp: '2024-11-14 10:30:00',
       hash: 'abc123def456',
       env: 'production'
     }
   });
   // call init function to setup event listners
   initSnailTrailDebugger();

<!-- _includes/debug.html -->
<script>
  window.__BUILD_TIMESTAMP__ = '{{ site.time | date: "%Y-%m-%d %H:%M:%S" }}';
  window.__BUILD_HASH__ = '{{ site.github.build_revision }}';
  window.__BUILD_ENV__ = '{{ jekyll.environment }}';
</script>
<script src="{{ '/assets/js/snail-trail-debugger.js' | relative_url }}"></script>

<!-- In your layout -->
{% if jekyll.environment == "development" %}
  {% include debug.html %}
{% endif %}

// .eleventy.js
eleventyConfig.addShortcode("buildInfo", function() {
  return `
    <script>
      window.__BUILD_TIMESTAMP__ = '${new Date().toISOString()}';
      window.__BUILD_HASH__ = '${process.env.GIT_COMMIT || 'local'}';
      window.__BUILD_ENV__ = '${process.env.ELEVENTY_ENV || 'development'}';
    </script>
  `;
});

<!-- _includes/layouts/base.njk -->
{% if env == "development" %}
  {% buildInfo %}
  <script src="/assets/js/snail-trail-debugger.js"></script>
{% endif %}

<!-- layout🔸 s/partials/debug.html -->
<script>
  window.__BUILD_TIMESTAMP__ = '{{ now.Format "2006-01-02 15:04:05" }}';
  window.__BUILD_HASH__ = '{{ getenv "GIT_COMMIT" }}';
  window.__BUILD_ENV__ = '{{ hugo.Environment }}';
</script>
<script src="{{ "js/snail-trail-debugger.js" | relURL }}"></script>

<!-- In your baseof.html -->
{{ if eq hugo.Environment "development" }}
  {{ partial "debug.html" . }}
{{ end }}

• Page load time
• Time to First Byte (TTFB)
• First Contentful Paint (FCP)
• Largest Contentful Paint (LCP)
• DNS lookup & TCP connection times
• Top 5 slowest resources

• Total page weight
• Failed resources count
• All loaded scripts with sizes and load times
• All stylesheets with metrics
• Images with dimensions and sizes

• Current URL
• User agent
• Viewport dimensions
• Screen resolution & pixel ratio
• Color scheme preference (dark/light)
• Connection type (4G, WiFi, etc.)

• LocalStorage size
• SessionStorage size
• Cookies (names only)
• Active event listeners estimate
• Real-time console log capture (last 20 messages)

• Total DOM nodes
• Maximum DOM depth
• Iframe count
• Forms count
• Images without alt attributes
• Internal vs external links

• Build timestamp
• Git commit hash
• Environment (dev/staging/prod)
• Build Environment

The debugger includes minimal default styles. You can customize by targeting these classes:

.debug-panel { /* Main container */ }
.debug-handle { /* Drag handle */ }
.debug-controls { /* Top control bar */ }
.debug-tabs { /* Tab buttons */ }
.debug-content { /* Content area */ }
.tab-content { /* Individual tab panels */ }
.debug-list { /* List items */ }

// Refresh all data
window.snailDebugger.refresh();

// Destroy and remove panel
window.snailDebugger.destroy();

// Access console log programmatically
console.log(window.snailDebugger.consoleLog);

• Local Development - Monitor performance during development
• Client Demos - Show technical metrics to stakeholders
• Mobile Testing - Debug without remote DevTools
• Performance Audits - Quick performance overview
• Accessibility Checks - Find images missing alt attributes
• Build Verification - Confirm correct build artifacts deployed

1. Only enable in development - Use environment checks in your templates
2. Inject build info - Makes debugging production issues easier
3. Use keyboard shortcut - Quick toggle without scrolling
4. Monitor console tab - Catch JavaScript errors early
5. Check failed resources - Identify broken asset links

The debugger only collects client-side data that's already accessible through the browser. It does not:

• Send data to external servers
• Access sensitive cookie values
• Expose server-side information
• Store data beyond LocalStorage

However, always disable in production unless needed for specific debugging scenarios.

Panel doesn't appear:

• Check localStorage.__snail_debug is set to 'true' (string, not boolean)
• Ensure script is loaded after DOM is ready
• Check browser console for JavaScript errors

Build info shows "Not configured":

• Verify build variables are being injected
• Check window.__BUILD_TIMESTAMP__ etc. are defined before debugger initializes

Performance metrics show N/A:

• Some metrics require HTTPS (like connection type)
• LCP requires user interaction on some browsers
• Wait for full page load before checking

MIT License - feel free to use in personal and commercial projects.

• Laravel Debug Bar by Taylor Otwell
• Symfony Web Debug Toolbar by Fabien Potencier
• Browser DevTools by Google

Contributions welcome! Please feel free to submit a Pull Request.

• 🐛 Report a bug
• 💡 Request a feature
• 📖 Documentation

Made with 🐌 and ☕ for the static site community