In a large operation the problem is rarely building something new: it is changing what already works without anyone noticing.
We work with companies where the system we are about to touch bills every day. That imposes a way of working: phased migrations, old and new living side by side, and the ability to roll back any deployment.
We do not arrive proposing to rewrite everything. We arrive to understand which part is slowing the business down and change that, on a path your risk team can approve.
It works, but every change is a risk and the person who understood it has left.
Two systems that should talk and a team syncing them with files.
The same indicator differs by who calculates it, and nobody knows which is right.
You must prove traceability and access control on something never designed for it.
Undocumented code and an expiring contract. It has to be picked up without stopping work.
The invoice grows every month and nobody can attribute it to a concrete change.
Two or three weeks to know what is there, what slows it down and what fixing it costs.