# Design a warehouse management system: system design interview question

> Physical stock and digital records must agree while workers receive, move, pick, and pack goods at the same time.

Source: https://sysround.com/questions/design-warehouse-management-system
Updated: 2026-11-05


Difficulty: hard. Levels: Senior, Staff+.

## How the interviewer opens it

"Design a warehouse system that receives stock, assigns storage locations, and coordinates workers who pick and pack orders. Keep inventory accurate while workers perform tasks at the same time."

## What to clarify first

- Warehouse scale
- Daily volume
- Request volume and mix
- Receipts and storage rules
- Order rules
- Latency
- Consistency and availability
- Workers and devices
- Durability and audit
- Scope limits

## Scope of a strong answer

Core requirements:

- Receive known SKUs and assign compatible storage locations.
- Reserve stock for orders and assign pick tasks.
- Confirm physical moves and pack complete orders.
- Maintain accurate stock through concurrent work, retries, and reported discrepancies.

Usually out of scope:

- Purchase plans and supplier payments.
- Carrier selection and shipment status.
- Robot control.
- Transfers between warehouses.
- Lot numbers, serial numbers, and expiry dates.
- Returns.

## What interviewers probe

### Stock for concurrent orders

Several orders can request the last units while workers move stock. A server failure must not erase an accepted reservation.

### Locations for new stock

Concurrent receipts can claim the same free space before either worker moves the goods.

### Work after device failures

A worker can move goods before the server receives confirmation. A device failure can leave the stock location uncertain.

### Missing stock before pack confirmation

A reservation does not prove that an item exists. A matching SKU in a tote does not prove that the order owns it.

## Common mistakes

- Uses one inventory quantity without locations, reservations, or stock states.
- Checks stock or free space without an atomic claim.
- Omits links from pick tasks to allocations or from totes to orders.
- Subtracts the same stock during both the pick and the pack steps.
- Assumes a database transaction also guarantees the physical move.
- Promises no data loss without durable replication and safe failover.

## The bar by level

- **Senior:** Defines quantity and capacity rules across each move. Links each pick to its exact allocation. Handles partial picks, deadlocks, stale confirmations, and missing stock. Defines durable commit acknowledgments and recovery after uncertain physical work.
- **Staff+:** Defines authority for stock commitments, task ownership, and failover. Explains which replica can safely accept writes after failure. Uses scoped recovery and audit records to repair stock without a warehouse-wide stop. Explains which guarantees must change for offline work or orders across warehouses.

Practice this question with an AI interviewer: https://sysround.com/practice/new?problem=warehouse-fulfillment


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SysRound (https://sysround.com) is an AI practice tool for system design interviews. It has a voice or typed AI interviewer and a shared whiteboard. At the end, you get feedback on each skill and a model answer. The AI feedback can be wrong.