What does it really take to migrate a large-scale, Fintech, and used by millions production app to Flutter—fast, safely, and without breaking the business or user trust? In this talk, I'm gonna share the behind-the-scenes story of how the Tamara app was migrated from native to Flutter in just 10 weeks. This isn’t a “hello world” migration—this is real-world engineering under pressure: undocumented business logic buried in Jira tickets, teams with mixed backgrounds, and the constant challenge of moving fast without things catching fire. From convincing stakeholders to trust the move, to onboarding engineers and building internal tooling powered by AI, this session dives deep into the practical decisions, trade-offs, and battle-tested strategies that made the migration possible. If you’re thinking about Flutter at scale—or already in the middle of the chaos—this talk will give you a realistic playbook (with a few scars and lessons along the way).