@Sivaluxan NiFi exposes APIs for a lot of endpoints. So not really sure what you are trying to accomplish in your use case. If you want to use a third party app to access info exposed by NiF that is possible. Or are you trying to setup some custom endpoint to expose some custom data?
You can also find the NIFi rest-api documentation for your installed release directly in the application via the global menu ( 3 horizontal lines upper right corner of UI) --> help.
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