Drop shipping businesses handle inventory synchronization with suppliers through:

1. API Integration: Connecting their store to the supplier's inventory system via API.

2. Regular Inventory Updates: Receiving frequent updates from suppliers on stock levels.

3. Automated Inventory Syncing Tools: Using third-party tools to sync inventory in real-time.

4. Manual Inventory Checks: Regularly checking supplier inventory levels manually.

5. Dropshipping Plugins: Utilizing plugins like Oberlo, AliExpress, or Dsers to sync inventory.

6. Supplier Feed Integration: Importing supplier product feeds to update inventory.

7. Custom Solutions: Developing custom solutions with suppliers for inventory synchronization.

8. Inventory Management Software: Using software like TradeGecko or Zoho Inventory to manage and sync inventory.

9. Supplier Communication: Regular communication with suppliers to ensure accurate inventory levels.

10. Inventory Buffering: Maintaining a buffer stock to account for discrepancies.

By implementing these methods, drop shipping businesses can ensure accurate inventory levels, reduce overselling, and improve order fulfillment rates.