Invoke service call on task completion in synch manner

Hi Community,

I am using Camunda for implementation of human approval use case. I am at very initial stages and new to Camunda.

During the execution of one workflow there might be various approval processes involved and there might be multiple approvers of the task.

For achieveing this i am using marker option from Camunda. I am planning to build custom dashboard in React to show all user task’s list
and call Camunda task API to complete the task from React.

On My web app i will give options like approve or reject to complete the task.

However i have one use case where I need to Call application service ( GraphQL ) endpoint in case Task is approved and show the success or failure message on react web application screen to the user.

If there are 2 approvers then application service call should be done only after both approvers have approved.

Kindly suggest how can this be modelled