We start by understanding the existing system. Not a surface-level architecture diagram, but a working understanding of where the business logic lives, what the data dependencies are, and which assumptions are load-bearing. We use AI-assisted tooling to compress this discovery from months to weeks.
Then we build a migration plan with phases, rollback conditions, and validation checkpoints. Every phase delivers working software. We don't disappear for six months and come back with a demo. We ship continuously and validate continuously.
At the end, the deliverable is a documented system with near-complete test coverage, automated deployment, and code the next engineer can read and build on.