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The Axes section in the Style tab controls the appearance and behavior of the X axis and Y axis (or left and right Y axes in dual-axis charts). Most axis settings are available for all Vega-based chart types (bar, line, area, scatter, heatmap).

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X axis

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Y axis (left)

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Dual Y axis (right axis)

Add a second Y axis on the right side of the chart to plot a series on a different scale. This is useful for combining measures with different units or magnitudes — for example, showing order count on the left axis and average order value on the right. To use the right axis:
  1. In the Series configuration for a specific series, change the Y axis assignment from Left to Right.
  2. The right axis settings appear in the Style tab — configure its title, labels, and scale independently from the left axis.

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Reference lines

Add horizontal reference lines to mark a target, threshold, or benchmark value. Reference lines appear at a fixed Y value across the full width of the chart. To add a reference line:
  1. In the Y axis section of the Style tab, click Add reference line.
  2. Set the Value — the Y position of the line.
  3. Optionally set a Label that appears next to the line.
  4. Configure Color and Style (solid, dashed, or dotted).
You can add multiple reference lines to the same axis. Each is configured independently.
Reference lines are only available on the left Y axis. For right-axis reference lines, use a custom Vega-Lite spec.