An exact solution method for the capacitated item-sharing and crowdshipping problem

•We propose an exact method for a combined item-sharing and crowdshipping problem.•A detour routing is required when crowdshippers are assigned multiple delivery jobs.•Previous methods cannot handle this generalization in combination with item-sharing.•An integrated platform with detour routing is the most profitable platform concept.•Incentivizing crowdshipping capacity is particularly profitable with low densities.