Why Copying Production Data to Staging Is a GDPR Risk (and What Developers Can Do Instead)

Many teams copy production databases into staging environments for testing.
It’s convenient because QA gets realistic data.

But if that dataset contains customer emails, phone numbers, or addresses, it may violate GDPR.

Developers often mask a few obvious fields like email or phone numbers, but other sensitive data remains.

One solution is deterministic masking - where the same input always produces the same masked value.
Example:
[e-mail] → [e-mail]
[e-mail] → [e-mail]

While exploring this problem, I built a small tool called DMasker to experiment with deterministic masking for staging datasets.

dmasker.com

It allows teams to upload a CSV dataset, define masking rules per column, and generate a safe version of the data.

I'm curious how other teams handle staging data safely.
Do you mask production data, generate synthetic datasets, or use another approach?