Tracksuit data is collected in monthly survey waves. Understanding how waves are dated and when they become available saves you the two most common surprises: date errors, and a month that "isn't there yet".
Waves are monthly, dated to the 1st
Each wave represents a month of survey data and is dated to the first day of that month. This is why start_period and end_period must be the 1st of a month, they map directly to wave dates. Any other day returns an error.
# Correct â first of the month ?start_period=2025-01-01&end_period=2025-06-01 # Errors â not a wave date ?start_period=2025-01-15&end_period=2025-06-30
A month isn't available until its wave closes
A given month's data only appears once that survey wave has closed and been processed. If you query a period that hasn't been published yet, you won't get data for it. As a rule, pull the most recently completed month, not the current one.
Figures are stable once published
Once a wave is published, its numbers don't change from one pull to the next. A period you pulled last month will return the same value today.
Smoothing and how it interacts with waves
By default the API applies a 3-month rolling average (smoothing=3mo), matching the dashboard. This means a single wave's figure is blended with the two before it.
You can set smoothing anywhere from 1mo to 1y; 1mo gives a single, non-smoothed wave value (which isn't available in the dashboard itself).
Because data only changes monthly, most integrations only need to pull once a month per category view. There's no benefit to polling more often.