3 platforms. 1 release window. R$22M in transactions protected.
In January, Brazil's tax authority announced that starting July 2026, business tax IDs (CNPJs) would include letters, not just numbers. For a financial institution that processed R$22M in transactions (instant payments + wire transfers) between January and July, this was a direct risk — alphanumeric IDs would be rejected by existing validations, locking up the operation.
External dependencies: our banking-as-a-service provider, the tax authority and the central bank. Any misreading of the requirements would become a production bug, with no room to roll back.
I prioritized the control panel over the apps — that's where most of the complexity lived (20+ endpoints). I mapped the provider, tax authority and central bank documentation before opening a single ticket. I ran backend and frontend refinement in parallel, and brought QA in early to design test scenarios before development started.
Documentation mapped → control panel set as the starting point → backend and frontend refining in parallel → QA scenarios ready before the code → single release, no rollback.
Start with the control panel, not the apps.
WhyIt concentrated the most complexity (20+ endpoints); validating it first reduced risk on mobile.
ImpactMobile behavior became easier to estimate and test.
Map all external documentation before refinement.
WhyThree separate regulatory sources, outside the team's direct control; a misread becomes a wrong requirement.
ImpactRefinement started from verified requirements, not assumptions.
QA designing scenarios before development.
WhyA single release with no rollback; anything not mapped in advance would only surface in production.
Impact100% technical coverage in validation.
Bringing the right people in to design scenarios before development made it possible to map out blockers that would otherwise only surface later: bill remittance requirements, cross-platform dependencies, and behavior in online banking and in the apps.
Aligning teams before building stopped being a one-off practice and became the mindset I carry into every new project.