In a turn-key project the main contractor is responsible to the client for the entire result and delivers a building or house to the client completely finished and ready to use. A turnkey project is a type of construction or business project in which the contractor or provider is responsible for delivering a complete and fully functional project to the client or owner. In a turnkey project, the client essentially “turns the key” and can start using or operating the project immediately after its completion, without the need for further involvement or management.