How do I keep my data safe during development? — answered by Engineer Saeed Baatiah
Three practical rules: do not hand over real customer data during development — use test data, or real data with names and numbers masked. Create separate revocable access accounts for the developer rather than sharing your own password. And record a contractual commitment to delete any local copy of the data after delivery. Those three cost you an hour of setup and remove an open-ended risk.