Ask HN: How do you create demo environments?

At the company I work at, we regularly need to provision demo environments with a specific set of features (or that behave in certain way), sometimes to show prospective clients or investors. Our application also connects with some external services (Plaid, Xero etc).

How do you do this (if at all) at the company you work at?

Sometimes features can only be demonstrated when certain data exists in a user's Xero account and might involve modifying the data in Xero. Manually importing/creating this would be time-consuming. Should we mock these parts of our application by creating a demo-specific version?