Synchronizing data between data structures for cross-merchant transactions

This disclosure describes, in part, techniques for synchronizing data between merchants' inventories, and techniques for utilizing the data synchronization to process cross-merchant transactions. For instance, a system may store a first inventory of items indicating first items offered for purchase by a first merchant and a second inventory of items indicating second items offered for purchase by a second merchant. The system may then analyze the first inventory of items with respect to the second inventory of items to determine that the second merchant should offer a first item from the first items for purchase at a physical establishment of the second merchant on behalf of the first merchant. The system can then provide a merchant device of the second merchant with access to the second inventory of items and the first item from the first inventory of items.