if reimbursement of exp done in course of providing of service thn reimbursement to be consider as a service consideration and service tax have to be applicable :- In service tax
Same concept here in gst if reimbursement is done in course or providing of service or dealing in goods thn it's include in consideration of provider of service or supply
now point comes to what will be done as per gst....whether gst applicable or not?? simple answer is :- if there are relation exist of employee - employer thn no gst if there are other relation like transporter service provider- reciever thn gst applicable if these service not in employment