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ScrollTracker / Visualization

ScrollTracker Heatmap

See where visitors engage, scan or skip.

Load a full-page screenshot and ScrollTracker data from BigQuery. Filter by page, inspect each scroll zone and export the overlay as a PNG. Your imported files are processed in this browser.

ScrollTracker test page

Build a heatmap

Preview

  • Engaged
  • Scanned
  • Skipped

No heatmap yet

Choose a screenshot and add scroll data, then select Generate overlay.

BigQuery SQL reference

-- ScrollTracker events: aggregated by page, zone, engagement type SELECT page_location, ep.value.int_value AS scroll_pct, (SELECT value.string_value FROM UNNEST(event_params) WHERE key = 'scroll_type') AS scroll_type, COUNT(*) AS event_count, AVG((SELECT value.int_value FROM UNNEST(event_params) WHERE key = 'dwell_ms')) AS avg_dwell_ms, AVG((SELECT value.double_value FROM UNNEST(event_params) WHERE key = 'avg_velocity')) AS avg_velocity FROM `project.dataset.events_*`, UNNEST(event_params) AS ep WHERE event_name = 'content_scroll' AND ep.key = 'scroll_pct' AND _TABLE_SUFFIX BETWEEN '20260327' AND '20260404' GROUP BY page_location, scroll_pct, scroll_type ORDER BY page_location, scroll_pct, scroll_type
Simple: SELECT * (raw events)
SELECT * FROM `project.dataset.events_*` WHERE event_name = 'content_scroll' AND _TABLE_SUFFIX BETWEEN '20260326' AND '20260404'

Export as JSON or JSONL. The tool auto-detects all formats: GA4 raw (nested event_params), pre-aggregated, and flat JSONL. No transformation needed.

Supported Formats
// Format 1: GA4 raw (SELECT * export) { "event_name": "content_scroll", "event_params": [ {"key": "scroll_pct", "value": {"int_value": 25}}, {"key": "scroll_type", "value": {"string_value": "engaged"}}, {"key": "dwell_ms", "value": {"int_value": 31588}}, {"key": "avg_velocity", "value": {"double_value": 1.06}} ] } // Format 2: Pre-aggregated JSON { "zones": [ { "scroll_pct": 25, "scroll_type": "engaged", "event_count": 15, "avg_dwell_ms": 31588, "avg_velocity": 1.06 } ] } // JSONL (one event per line) {"scroll_pct":25,"scroll_type":"engaged","dwell_ms":31588,"avg_velocity":1.06} {"scroll_pct":25,"scroll_type":"skipped","dwell_ms":162,"avg_velocity":72.89}