Why does a daily payload look missing for one day?

This is a timezone boundary effect, not missing data.

This is a timezone boundary effect, not missing data. When a user is in a non-UTC timezone, a day's daily payload can have a UTC start_time that falls on the previous (or next) calendar day, so a query keyed to the local date can miss it.

How to handle it:

• Expand your query date range by one day on each side, then filter on your side using the timezone offset in the metadata to determine the actual local date.

• For daily, body, and nutrition events (which span midnight-to-midnight calendar days), use only the date part of start_time as your record identifier, rather than the full timestamp.

• When a provider does not supply a UTC offset, Terra omits it rather than sending a false one.

If you need to pause ingestion to migrate, return an error code (for example, 502) so webhooks are retried later rather than dropped. See receiving data updates for retry behaviour.