Heatmap

The heatmap widget plots a single metric across two categorical axes, using color intensity to represent the value in each cell. It is the go-to chart for spotting activity patterns — when your users are most active, which combinations are hot or cold.

Use it for:

• Activity by hour of day × day of week
• Events by platform × country
• Any metric you want to compare across two dimensions at once

---

Query requirements

Return exactly three columns: two axis columns and one numeric value column.

• The first non-value column is the X axis.
• The second non-value column is the Y axis.
• The numeric column (alias it count or value) drives the cell color.

GROUP BY both axis columns.

Simple mode (recommended)

Select

toHour(timestamp)       AS hour,
toDayOfWeek(timestamp)  AS weekday,
count()                 AS count

Filters

WHERE name = 'app_started'
GROUP BY hour, weekday

Equivalent full SQL

SELECT toHour(timestamp) AS hour, toDayOfWeek(timestamp) AS weekday, count() AS count
FROM {table}
WHERE name = 'app_started'
GROUP BY hour, weekday

Result shape:

hour	weekday	count
18	5	320
19	5	410
20	6	380

Note

For the classic activity heatmap, output weekday as the number 1–7 from toDayOfWeek — the widget automatically maps 1 → Mon … 7 → Sun. Leave hour as the number 0–23.

---

Common examples

Activity by hour × weekday

Select: toHour(timestamp) AS hour, toDayOfWeek(timestamp) AS weekday, count() AS count
Filters: WHERE name = 'app_started' GROUP BY hour, weekday

---

Events by platform × country

Select: platform, country, count() AS count
Filters: GROUP BY platform, country