How do I rotate project api secrets?

You can rotate (reset) a project’s API secret yourself from the Mixpanel UI:

This will generate a new project secret; you’ll then need to update any scripts or integrations that authenticate with the old secret.

Is there any overlap to retain the old key for some amount of time?

kapa.ai

Sorry Denny J., I'm not sure what you mean. Please try again. 👋

kapa.ai Is there any overlap to retain the old key for some amount of time?

The knowledge sources do not mention any grace period or overlap where both the old and new project API secrets work at the same time.

All that’s documented is:

There is no explicit statement that the old secret remains valid after reset, nor that there is any overlap window. For an authoritative answer on behavior at the exact moment of rotation, you’d need to contact Mixpanel Support.