Advanced Features

    Visual diff thresholds explained

    Tune how sensitive visual monitoring is — from tiny pixel shifts to major layout changes.

    Part of Visual monitoring — the full answer, the facts and the alternatives in one place.

    Updated 2026-07-09
    2 min read
    visual monitoring
    thresholds
    sensitivity

    Quick answer#

    Sensitivity is a 0–100 slider. Lower = more sensitive (any pixel change alerts). Higher = only large layout changes alert. Default is 5% — good for most marketing pages.

    What it controls#

  1. The percentage of pixels that must differ before an alert fires
  2. Whether antialiasing and minor color shifts count as changes
  3. How text-diff scoring is weighted against pixel-diff scoring

    4. Where to find it in Lemwatch#

    Visual Monitoring → [page] → Settings → Sensitivity slider.

    How to tune it#

  4. Start at the default (5%).
  5. If you get noisy alerts on rotating banners or ads, raise to 10–15%.
  6. If you're missing small text edits (typos, price changes), lower to 2%.
  7. For legal/pricing pages, combine a low threshold with an ignore zone over dynamic areas.
  8. Save. The next run uses the new threshold.

    9. FAQ#

    Why did a change below my threshold still alert?#

    Text diff scores separately. A single character change on a page with words counts even if pixel diff is under threshold.

    Can I have different thresholds per page?#

    Yes — thresholds are per-page, not per-site.

    Related#

  9. Visual monitoring setup
  10. Ignore zones
  11. Reducing visual noise
    12. Was this article helpful?

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    Add a page to visual monitoring, pick a schedule, and get pixel-diff alerts when it changes.

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    Reducing false visual alerts

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    What is the Money Page Monitor?

    The Money Page Monitor auto-detects your revenue-critical pages (pricing, checkout, signup) and applies tighter uptime and content assertions.

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