Hello, CTO of Kong here. You mean a client to consume the Admin API in order to create entities on Kong? If that's the case the community has built lots of open source clients in pretty much any language that would make the job of integrating Kong within an existing system much easier. The community around Kong has also built declarative configuration support that you can use instead of the Admin API.

Our official declarative configuration will also be released very soon, and in some environments (like Kubernetes) we already support it.