Payments, authentication, AI features and recurring billing. Four playbooks, four practice sandboxes, and the release gate for each.
Bought separately these are $176. Together they are $98.
The edge cases that cost real money. Sandbox with 18 verified defects, 18 checks that gate a release, 96 more behind them, 52-page playbook.
Where the application works perfectly, including for the attacker. Sandbox with 18 verified defects, 18 checks that gate a release, 75 more behind them, 28-page playbook.
How to test a system that answers differently every time. Sandbox with 18 verified defects, 18 checks that gate a release, 77 more behind them, 27-page playbook.
Defects that arrive every month until somebody notices. Sandbox with 18 verified defects, 18 checks that gate a release, 81 more behind them, 26-page playbook.
Because the domains leak into each other, and the second volume is where that becomes obvious.
The reconciliation habit you learn in payments is what catches a billing defect three months later. The session-handling checks in authentication are the ones that matter when a subscription is cancelled and access does not stop. The evaluation discipline in the AI volume is the same discipline the payment sign-off sheet needs.
One volume teaches a domain. Four teach a method.
One download. Four playbooks, four case banks, four sandboxes, four smoke tests. No subscription, no account.
Buy the series — $98International · card, PayPal · save $78 কিনুন — ৳5,900Bangladesh · bKash, Nagad, cardEach volume has a live demo and a free 18-check smoke test. Run one against your own product first — if it finds nothing, do not buy anything.