Rehearsal
In short
Rehearsal runs the finished app on the Rehearsal Server, where you drill the data migration, walk the real journeys, and check security and running cost while it is still safe to be wrong.
Rehearsal is the stage most projects skip and most incidents come from. The app runs on the Rehearsal Server — real AWS infrastructure, configured the way production will be.
What you rehearse
- The data migration. Import from the old system with realistic volume, and do it more than once. The first run always teaches you something.
- The journeys. The people who will use the app walk through their real work, not a demo script.
- Security posture. Access, secrets, network boundaries, and what is exposed publicly.
- Running cost. What this will cost per month at your actual usage, before it is your production bill.
- Backups and restore. Prove a restore works while nothing depends on it.
Realistic data, safely
Rehearsal wants production-shaped data, which means production-shaped risk. Sensitive fields are masked when data is copied down, so the rehearsal is realistic without spreading personal data into a second environment.
Signs you are ready to leave
- The migration has run cleanly end-to-end, timed, with a rollback you have actually tested.
- No open findings you would be uncomfortable explaining after an incident.
- The monthly cost estimate is one you have accepted.
- Everyone knows what happens to the old system on the day.
Next: Live · Promoting between stages