AWS Cloud Migration Checklist: Moving a Legacy App to the Cloud

Cloud migration projects fail for predictable reasons. Not because the technology is hard but because AWS is well-documented and the tooling is mature. They fail because teams skip the audit phase, underestimate data migration complexity, and try to lift-and-shift architectures that were never designed for the cloud. I've led cloud migrations for US businesses across FinTech, healthcare, and SaaS from single-server monoliths to multi-region systems. This checklist captures what actually needs to happen before, during, and after migration. Phase 1: Pre-Migration Audit (Do Not Skip This) Before touching AWS, you need a complete picture of what you're moving. Application inventory: [ ] List every service, process, and scheduled job running on your current infrastructure [ ] Map all external dependencies: third-party APIs, payment processors, email providers [ ] Document every port, protocol, and network path between services [ ] Identify stateful vs stateless components: They migrate diff