Authenticating flowable-task from other application

Thanks Will !!
The REST endpoint which you provided : http://localhost:9999/flowable-task/process-api/runtime/process-instances worked fine.

And Yes, there is a similar API in flowable-task, used to start new Process Instance http://localhost:9999/flowable-task/app/rest/process-instances , which takes JSON object having value of processDefinitionId , which is again obtained from API http://localhost:9999/flowable-task/app/rest/process-definitions?latest=true , whose response is,

{
  "size": 1,
  "total": 1,
  "start": 0,
  "data": [
    {
      "id": "processdemo:2:b7e88899-c4c2-11e9-93d6-525349d6ad33",//processDefinitionId
      "name": "ProcessDemo",
      "description": null,
      "key": "processdemo",
      "category": "http://www.flowable.org/processdef",
      "version": 2,
      "deploymentId": "b7cb8ab6-c4c2-11e9-93d6-525349d6ad33",
      "tenantId": "",
      "hasStartForm": false
    }
  ]
}

When using above processDefinitionId as request body for API, http://localhost:9999/flowable-task/app/rest/process-instances , I am able to start the process from Swagger of flowable-ui-task, but if I try to start the process from POSTMAN, it behaves in the same way I described in my question. (process doesn’t get started and nothing happens in flowable-ui-task console in IDE)

I’m gonna use the endpoint which you provided, but I’m not sure why it doesn’t work