delivery-api

if an item is published, then you can check the exact time of publishing in deliver API response, in last_modified system field, as the act of publishing is considered the last modification.

regrettably, the only way to get timestamps of other workflow transitions is using the "compare versions" functionality in Kontent inventory, you can't achieve it through API.

what you can do however, is set up webhooks on particular workflow steps, which will fire whenever a transition occurs, informing your endpoint of that transition. a timestamp is part of the webhook's payload. for more info on webhooks, check kontent documentation: https://docs.kontent.ai/tutorials/develop-apps/integrate/using-webhooks-for-automatic-updates