Techniques for heuristic customer order fulfillment planning. A method may include iteratively partitioning ordered items into shipment groups according to a set partition algorithm. Of a working set including the unassigned items, the algorithm may determine the subset that optimizes fulfillment cost per member of the subset, and may assign this subset to a shipment group. To determine the subset, the algorithm may iterate over the set of combinations of fulfillment decision variables. For each combination, a list of members of the working set that may be shipped according to the combination is generated. The subset of this list that optimizes, per member of the subset, the costs of shipping according to the combination is then identified.