Introducing Size Change Monitoring: Detect Content Changes Before They Become Problems

What is Size Change Monitoring?

Your website’s file sizes tell a story. When a page suddenly grows from 20KB to 200KB, something changed—maybe an image was added, maybe your build process broke, or maybe someone injected malicious content. When a configuration file shrinks by 80%, you probably have a problem.

Size Change Monitoring tracks the file size of every link on your site and alerts you when changes exceed your configured thresholds.

Why Monitor File Sizes?

Security Detection

One of the first signs of a website compromise is unauthorized content injection. Attackers often add:

  • Cryptocurrency mining scripts (adds 50-200KB)
  • Spam link injections (adds 5-50KB)
  • Malware download scripts (varies widely)

If your homepage suddenly grows by 100KB overnight, you want to know immediately—not when Google flags you for malware.

Content Management Issues

  • Broken builds: A deployment failure might serve empty or truncated pages
  • Missing assets: CSS/JS files that fail to compile will be much smaller
  • Accidental deletions: Content removed from your CMS shows as size drops
  • Duplicate content: Copy-paste errors can double page sizes

Performance Monitoring

Page size directly impacts:

  • Load times (especially on mobile)
  • Bandwidth costs
  • SEO rankings (Core Web Vitals)

Tracking size over time helps identify bloat before it impacts users.

How It Works

Each monitored link can have its own size change threshold:

  • 5%: High sensitivity for critical pages (config files, API responses)
  • 10-20%: Standard sensitivity for content pages
  • 50%+: Low sensitivity for dynamic pages with variable content

Immediate Alerts

When a size change exceeds the threshold, you get:

  • Email notifications with before/after sizes
  • Slack/Discord messages for team awareness
  • Detailed change history in your dashboard

Size History Tracking

We store size measurements over time, letting you:

  • Spot gradual bloat trends
  • Correlate size changes with deployment dates
  • Generate reports on content growth

Real-World Example

Scenario: An e-commerce site’s product page template has a JavaScript error introduced during a deployment. The error prevents the reviews widget from loading.

Before monitoring: Customers complain about missing reviews. Support escalates to dev. Dev investigates. Time to detection: 4-6 hours.

With size monitoring:

  • Product page normally: 145KB
  • After broken deployment: 98KB (reviews widget JS missing)
  • Threshold set: 20%
  • Change detected: 32% decrease
  • Alert sent: Within 5 minutes of first check

Time to detection: 5 minutes

Setting Up Size Monitoring

1. Navigate to Monitor Settings

Open any monitor and go to the “Links” tab to see all discovered URLs.

2. Configure Thresholds

Click on any link to open its settings. Set:

  • Enable size monitoring: Toggle on
  • Change threshold: 5-100% (lower = more sensitive)
  • Alert on increase/decrease/both: Choose what matters

3. Review History

The size history panel shows all recorded sizes with timestamps, making it easy to correlate changes with deployments or content updates.

Best Practices

Start with Critical Pages

Don’t enable 5% thresholds everywhere—you’ll get noise from legitimate content updates. Focus on:

  • Homepage
  • API endpoints (if monitoring external services)
  • Configuration files
  • JavaScript/CSS bundles
  • Payment/checkout pages

Set Appropriate Thresholds

Page TypeSuggested Threshold
Static config/JSON5%
App bundles (JS/CSS)10%
Product pages20%
Blog posts30%
Dynamic feeds50%+

Combine with Other Monitoring

Size monitoring works best alongside:

  • Uptime monitoring: Catch pages that error out
  • Status code tracking: Detect 500 errors
  • Response time tracking: Spot slow pages

Available on All Plans

Size change monitoring is included in all HITS Scout plans, including Free. Every discovered link can have size monitoring enabled.

Start monitoring your site’s file sizes →

FAQ

Q: Does size monitoring use extra checks?
A: No. File size is recorded during regular link checks at no additional cost.

Q: What about gzip compression?
A: We measure the uncompressed content size for consistency. Compression ratios can vary, but content size is stable.

Q: Can I get alerts for size increases only?
A: Yes! You can configure alerts for increases, decreases, or both independently.

Q: How far back does size history go?
A: Size history follows your plan’s data retention: 7 days (Free), 30 days (Pro), or 90 days (Enterprise).