Why does generateWidgetSession return a 500?

For generateWidgetSession, the providers field must be a single comma-separated string (for example, "GARMIN,FITBIT,OURA"), not a JSON array or list.

For generateWidgetSession, the providers field must be a single comma-separated string (for example, "GARMIN,FITBIT,OURA"), not a JSON array or list. Passing an array triggers a 500.

This applies to the SDKs too: newer Python SDK versions changed the providers parameter from a list of strings to a comma-separated string.

One other cause to rule out: a 500 with a null message can also indicate an invalid dev-id/API-key combination (often env vars not loading), so log credential presence before the call.