A vendor takes the product from idea to working, deployed system — design, development, testing, launch, and handover — so the client receives something ready to use rather than parts to assemble.
It suits teams without in-house engineering, because coordination risk sits with the vendor. The trade-off is that the scope must be defined well enough to be contracted.
We deliver turnkey with the source code, infrastructure, and documentation handed over in full, so the result is yours to run or move elsewhere — turnkey should not mean dependent on us.