Managing inventory becomes more difficult when you sell through physical stores, marketplaces, and webstores.

Your POS may show 20 units of a product. Your accounting software may show 18. Shopee, Lazada, or your webstore may display a different quantity again.

When these figures do not match, which one should your team trust?

Every omnichannel retailer needs an inventory master system. This is the main business system that holds the official stock figure. All connected sales channels should receive their inventory information from this source.

For most retailers, the inventory master should be one of three systems:

1. Your POS system
2. Your accounting software
3. Your ERP system

The right choice depends on where your stock movements happen, which team controls inventory, and how complex your operations are.

What Is an Inventory Master System?

An inventory master system is the main source of truth for your stock quantities.

It controls or records important inventory movements such as:

1. Goods received from suppliers
2. Sales and stock deductions
3. Customer returns
4. Order cancellations
5. Warehouse and outlet transfers
6. Damaged or missing stock
7. Stock adjustments
8. Physical stock counts
9. Reserved stock

Other systems may keep copies of the inventory figure, but the master system has final authority.

For example, your inventory master shows 20 units of a product. A customer buys one unit through a marketplace. The order flows back to the master system, which deducts the sale and changes the official stock figure to 19.

The updated quantity can then be sent to your other connected marketplaces, webstores, and retail channels.

This creates a clear inventory flow:

Sale takes place → Order returns to the master system → Master stock is updated → New quantity is sent to all sales channels

Why Your Business Needs One Inventory Master

Problems begin when several systems can independently change the official stock quantity.

Consider this example:

1. Your POS records an in-store sale and deducts one unit.
2. Your accounting software imports the same transaction and deducts another unit.
3. A team member manually changes the quantity on a marketplace.
4. A connector sends an older stock figure to the webstore.
5. Every system begins showing a different quantity.

This can lead to:

1. Overselling
2. Cancelled customer orders
3. Incorrect replenishment decisions
4. Unnecessary stock transfers
5. Confusing inventory reports
6. Repeated manual corrections
7. Time-consuming investigations

It is normal for several systems to display inventory. The problem occurs when several systems believe they control it.

Your business needs one clear rule: only the inventory master determines the official stock figure.

Should Your POS, Accounting Software, or ERP Be the Inventory Master?

The best inventory master is usually the system closest to the physical movement of your stock.

Here is a simple comparison:

Let us look at each option more closely.

Option 1: Use Your POS as the Inventory Master

A point-of-sale system can be a suitable inventory master for a store-led retail business.

Your POS may be the right choice if:

1. Physical outlets generate most of your sales.
2. Store employees receive stock through the POS.
3. The POS tracks inventory by outlet.
4. Your team records transfers and adjustments in the POS.
5. Online and in-store sales use the same stock.
6. Physical stock counts are performed in the POS.

The main advantage is speed. When a customer buys an item at the counter, the POS can immediately reduce the available quantity.

This matters when the same item is also listed on marketplaces and webstores. The latest POS quantity can be sent to those channels to reduce the risk of selling stock that is no longer available.

Option 2: Use Your Accounting Software as the Inventory Master

Accounting software can work as the inventory master for a smaller business with simple stock operations.

This setup may suit your business if:

1. Purchasing is managed in the accounting system.
2. Goods received are recorded there first.
3. The finance or administration team controls stock adjustments.
4. You operate a small number of outlets or warehouses.
5. Your product and stock structure is straightforward.
6. Sales transactions can be sent back to the accounting software reliably.

Keeping purchasing, inventory, and financial records in the same system can make reconciliation easier. Your team can compare stock movements with supplier purchases, sales, and other accounting records.

 

Option 3: Use Your ERP as the Inventory Master

An enterprise resource planning system, or ERP, is often the best inventory master for larger retailers and businesses with complex supply chains.

An ERP may be suitable if you manage:

1. Multiple warehouses
2. Several retail outlets
3. Multiple business entities
4. Wholesale and retail orders
5. Complex purchasing processes
6. Stock transfers between locations
7. Product assembly or manufacturing
8. Detailed approval processes
9. High transaction volumes
10. Centralized supply chain planning

An ERP can connect inventory with purchasing, warehouse operations, fulfilment, finance, and reporting. This makes it a logical source of truth when many departments affect stock.

ERP integrations need clear planning

An ERP may offer strong inventory control, but the integration workflow can be more complex.

Your team must decide how to process:

1. New marketplace and webstore orders
2. Unpaid or unconfirmed orders
3. Customer cancellations
4. Returns and refunds
5. Failed deliveries
6. Reserved stock
7. Bundles and promotional sets
8. Stock transfers
9. Inventory adjustments

These rules should be agreed upon before connecting your ERP to multiple sales channels.

How to Choose the Right Inventory Master System

Do not choose a system simply because it is the newest or most familiar. Choose the one that best represents what physically happens to your stock.

Ask the following questions.

1. Where are goods received?

The system that records incoming goods is often a strong candidate.

Your stock should not become available for sale until your team has physically received, checked, and confirmed it. The inventory master should reflect this process accurately.

2. Where are most sales recorded?

If most sales happen in retail outlets, your POS may be the most practical master.

If sales come from many sources and pass through complex warehouse or finance processes, your ERP or accounting system may be more suitable.

3. Which system understands every stock location?

Your inventory master should know where the stock is located.

This may include:

1. Retail outlets
2. Main warehouses
3. Regional warehouses
4. Fulfilment centres
5. Goods-in-transit locations
6. Damaged-goods areas
7. Return-processing areas

A single total quantity may not be enough if different channels sell from different locations.

4. Which system records every stock movement?

The master system should receive all events that increase or decrease inventory.

These include purchases, sales, transfers, returns, cancellations, damaged goods, and manual adjustments.

If a system misses some of these events, it cannot maintain an accurate stock figure.

5. How quickly can the system update inventory?

The required speed depends on your sales volume.

A retailer that sells a few orders per day may manage with scheduled updates. A high-volume omnichannel retailer may need much faster synchronization.

Slow updates increase the risk that two channels will sell the final available unit at the same time.

6. Can it handle returns and cancellations correctly?

Inventory does not only decrease.

A cancelled order, returned item, rejected delivery, or failed payment may cause stock to become available again. Your master system needs clear rules for when that stock can be resold.

Returned items should not automatically become available if they still require inspection.

7. Which team owns inventory accuracy?

Technology alone cannot keep inventory accurate.

Your warehouse, retail, operations, or finance team must record stock movements correctly. Choose a system that the responsible team already uses and understands.

The business should also name an inventory owner who is responsible for investigating differences and approving adjustments.

8. Can it connect with your sales channels?

Your inventory master must share stock information with the places where you sell.

It also needs to receive orders from those channels so that it can update the official quantity.

If direct integrations are limited, an omnichannel platform such as Zetpy can connect the master system with marketplaces and webstores.

Rules That Prevent Conflicting Stock Updates

Choosing the right inventory master is only the first step. You also need clear rules for how systems and employees update stock.

Rule 1: Give One System Final Authority

Only the inventory master should decide the official stock quantity.

Marketplaces and webstores can display the available quantity. They can also send orders back to the business. However, they should not independently control or overwrite the main stock figure.

Rule 2: Define the Direction of Every Data Flow

Document where each type of information begins and where it goes.

For example:

1. Inventory quantity: Master system → Zetpy → Sales channels
2. Online orders: Sales channels → Zetpy → Master system
3. In-store sales: POS → Master system, if the POS is not already the master
4. Goods received: Purchasing process → Master system
5. Stock adjustments: Authorized team → Master system

Avoid sending the same inventory update through several different routes. This can create update loops, delays, and conflicting figures.

Rule 3: Separate Physical Stock From Available Stock

Physical stock and available stock are not always the same.

For example, you may physically have 20 units, but:

1. Three units are reserved for confirmed orders.
2. Two units are damaged.
3. One unit is being transferred.
4. Two units are kept as a safety buffer.

Your available quantity may therefore be only 12 units.

Define how your inventory master calculates available stock before sending quantities to sales channels.

Rule 4: Use Reserve Stock Where Necessary

You may not want to publish every available unit online.

For example, if your master system shows 10 available units, you may publish only eight. The remaining two units act as a safety buffer for delayed updates, stock damage, or simultaneous store sales.

Safety stock can reduce risk, but it does not replace accurate inventory synchronization.

Rule 5: Control Manual Inventory Changes

Employees should avoid changing quantities directly on individual marketplaces or webstores.

A manual change may be overwritten during the next synchronization. It can also create a difference that is difficult to investigate later.

Whenever possible, make the adjustment in the inventory master and let the updated figure flow to all connected channels.

If an emergency manual change is necessary, record who made it, why it was made, and how the master system will be corrected.

Rule 6: Prevent Duplicate Stock Deductions

A single sale should reduce stock only once.

For example, if an online order passes through Zetpy before reaching the ERP, the ERP should not receive the same order again through a second connection.

Use unique order references and clear integration routes to prevent duplicate transactions.

Rule 7: Create a Process for Failed Updates

No integration is completely free from interruptions.

Your team should know:

1. How failed updates are reported
2. Who is responsible for checking them
3. Whether the system retries automatically
4. How to correct rejected orders
5. How to reconcile stock after an outage
6. When online selling should be paused

A clear recovery process helps prevent a temporary connection issue from becoming a larger inventory problem.

Rule 8: Review Inventory Differences Regularly

Compare three figures regularly:

1. The physical quantity
2. The inventory master quantity
3. The quantity published to sales channels

If the figures differ, investigate the cause before making another adjustment.

Repeated differences may point to a larger issue, such as duplicate orders, missing returns, delayed updates, incorrect product mappings, or unrecorded stock movements.

How Zetpy Connects Your Inventory Master With Sales Channels

Your POS, accounting software, or ERP should remain the inventory master. Zetpy can help connect that system with your marketplaces and webstores.

A typical workflow may look like this:

1. Your POS, accounting software, or ERP holds the official stock figure.
2. Zetpy receives product and inventory information from the master system.
3. Zetpy sends the available quantity to connected marketplaces and webstores.
4. A customer places an order through one of those channels.
5. The order flows through Zetpy to the inventory master.
6. The master system processes the sale and deducts the stock.
7. Zetpy receives the latest quantity.
8. The updated quantity is sent to the connected sales channels.

This keeps inventory authority inside the system that controls your business operations.

Zetpy acts as the connection layer between that master system and the places where you sell. Depending on your setup and available integrations, this can help your team:

1. Reduce manual inventory updates
2. Maintain more consistent quantities across channels
3. Lower the risk of overselling
4. Connect online orders with retail or back-office operations
5. Process marketplace and webstore orders more efficiently
6. Create clearer responsibilities between systems
7. Spend less time correcting stock differences

The exact workflow depends on your software, sales channels, locations, and operating rules. Map the complete process before activating automated stock updates.

Final Recommendation

Your inventory master should be the POS, accounting software, or ERP system that most accurately reflects the physical movement of your stock.

Choose your POS if your operations are mainly led by retail outlets. Consider your accounting software if your inventory process is straightforward and closely connected to purchasing and finance. Choose an ERP if you manage complex warehouses, locations, supply chains, or transaction volumes.

Marketplaces and webstores should receive inventory from the chosen master. They should not control the main stock figure.

Whichever system you select, follow three basic principles:

• Maintain one official source of inventory.
• Define clear directions for every update.
• Send all sales back to the master system.

Zetpy can help connect your chosen inventory master with marketplaces and webstores, creating a clearer omnichannel inventory workflow.

Want to connect your POS, accounting software, or ERP with your online sales channels? Contact Zetpy to discuss an inventory workflow that fits your business.

Frequently Asked Questions

What is an inventory master system?

An inventory master system is the main source of truth for stock quantities. It controls the official inventory figure and shares that information with connected sales channels.

Which system should be the inventory master?

The inventory master should usually be your POS, accounting software, or ERP. The right choice depends on where stock movements are recorded, how many locations you manage, and how complex your operations are.

Can a marketplace or webstore be the inventory master?

For an omnichannel retail setup, marketplaces and webstores should act as sales channels. They should receive inventory from the chosen POS, accounting system, or ERP and return orders for processing.

Is a POS suitable as an inventory master?

A POS can be suitable for store-led retailers when it records counter sales, goods received, stock transfers, adjustments, and inventory by outlet.

When should an ERP be the inventory master?

An ERP is often suitable when a business has multiple warehouses, complex purchasing, several entities, manufacturing, wholesale orders, or detailed supply chain processes.

Can accounting software be the inventory master?

Yes, accounting software can work for businesses with straightforward inventory operations. It must be able to receive orders, update stock promptly, manage different stock movements, and share accurate quantities with connected systems.

How does Zetpy support the inventory master?

Zetpy can connect the chosen POS, accounting software, or ERP with marketplaces and webstores. It helps inventory updates move to sales channels while orders return to the master system for processing.

11:16 AM

Replace the current “How Zetpy Connects Your Inventory Master With Sales Channels” section with the following:

How Zetpy Helps During the Order Sync Delay

Your POS, accounting software, or ERP remains the inventory master. However, a marketplace order may take some time to flow back into that system.

This delay creates a risk. If the available quantity is not updated quickly, another customer may purchase the same stock through a different marketplace or webstore.

Zetpy helps manage this timing gap.

When an online order first arrives in Zetpy, Zetpy immediately reduces the available online inventory and sends the updated quantity to the connected sales channels. The order then flows back to the inventory master for processing.

Once the order reaches the POS, accounting software, or ERP, the master system records the sale and deducts the quantity from its official inventory figure.

For example, your inventory master shows 20 units:

1. Zetpy receives an order for one unit from a marketplace.
2. Zetpy immediately reduces the available online quantity from 20 to 19.
3. Zetpy sends the new available quantity to the other connected marketplaces and webstores.
4. The order flows from Zetpy into the inventory master.
5. The inventory master records the sale and updates its official quantity from 20 to 19.
6. The latest master quantity is synchronized through Zetpy to the connected sales channels.

This is not a duplicate stock deduction. Zetpy first adjusts the quantity available for online selling. The master system later records the official inventory movement when it receives the order.

This two-stage process helps reduce the chance of overselling while orders are still being transferred to the inventory master.

The inventory flow becomes:

Marketplace order received → Zetpy reduces online available stock → Updated quantity is sent to connected channels → Order flows to the inventory master → Master system records the official deduction

Depending on your system setup and available integrations, this can help your team:

• Respond to online orders more quickly
• Reduce overselling during synchronization delays
• Keep marketplace and webstore quantities aligned
• Maintain the POS, accounting software, or ERP as the official inventory master
• Connect online orders with retail and back-office operations
• Reduce manual inventory updates

The exact workflow depends on your software, sales channels, and integration setup. Your team should map the complete order and inventory flow before activating automated updates.

Also replace the earlier example under “What Is an Inventory Master System?” with:

For example, your inventory master shows 20 units of a product. A customer buys one unit through a marketplace. Zetpy first reduces the inventory available across the connected online channels. The order then flows back to the inventory master, which records the official stock deduction and updates its quantity to 19.

And update the inventory flow line to:

Marketplace sale → Zetpy reduces online available stock → Order returns to the master system → Master stock is updated → Latest quantity is synchronized to connected sales channels

1:14 PM

Updated the full article and improved the flow throughout.

The revised version clearly explains that:

• Zetpy reduces the available online inventory immediately when an order arrives.
• This protects stock during the delay before the order reaches the master system.
• The POS, accounting software, or ERP later records the official deduction.
• These are two stages of one transaction, not duplicate stock deductions.
• Marketplaces and webstores remain sales channels, not inventory masters.

[Download the updated article](/Users/adrian/Documents/Codex/2026-09-02/3-which-system-should-be-your/outputs/inventory-master-system-article.md)

1:18 PM

Which System Should Be Your Inventory Master?

Meta description: Learn whether your POS, accounting software, or ERP should be the inventory master system for your omnichannel retail business.

Suggested URL slug: /choose-inventory-master-system

Managing inventory becomes more difficult when you sell through physical stores, marketplaces, and webstores.

Your POS may show 20 units of a product. Your accounting software may show 18. Shopee, Lazada, or your webstore may display a different quantity again.

When these figures do not match, which one should your team trust?

Every omnichannel retailer needs an inventory master system. This is the main business system that holds the official stock figure and receives orders from your connected sales channels.

For most retailers, the inventory master should be one of three systems:

• Your POS system
• Your accounting software
• Your ERP system

The right choice depends on where stock movements happen, which team controls inventory, and how complex your operations are.

What Is an Inventory Master System?

An inventory master system is the main source of truth for your stock quantities.

It controls or records important inventory movements such as:

• Goods received from suppliers
• Sales and stock deductions
• Customer returns
• Order cancellations
• Warehouse and outlet transfers
• Damaged or missing stock
• Stock adjustments
• Physical stock counts
• Reserved stock

Other systems may display or temporarily reserve inventory, but the master system has final authority over the official stock figure.

For example, your inventory master shows 20 units of a product. A customer buys one unit through a marketplace. Zetpy receives the order and immediately reduces the quantity available across your connected online sales channels from 20 to 19.

The order then flows back through Zetpy to the inventory master. When the POS, accounting software, or ERP receives the order, it records the sale and updates the official stock figure from 20 to 19.

This creates a clear inventory flow:

Marketplace order received → Zetpy reduces available online stock → Updated quantity is sent to connected channels → Order flows to the master system → Master system records the official deduction

This is not a duplicate deduction. Zetpy first adjusts the quantity available for online selling. The master system later records the official stock movement when it receives the order.

Why Your Business Needs One Inventory Master

Problems begin when several systems can independently change the official stock quantity.

Consider this example:

1. Your POS records an in-store sale and deducts one unit.
2. Your accounting software imports the same transaction and deducts another unit.
3. A team member manually changes the quantity on a marketplace.
4. A connector sends an older stock figure to the webstore.
5. Every system begins showing a different quantity.

This can lead to:

• Overselling
• Cancelled customer orders
• Incorrect replenishment decisions
• Unnecessary stock transfers
• Confusing inventory reports
• Repeated manual corrections
• Time-consuming investigations

It is normal for several systems to display inventory. The problem occurs when several systems believe they control the official figure.

Your business needs one clear rule: only the inventory master determines the official stock quantity.

Should Your POS, Accounting Software, or ERP Be the Inventory Master?

The best inventory master is usually the system closest to the physical movement of your stock.

Let us look at each option more closely.

Option 1: Use Your POS as the Inventory Master

A point-of-sale system can be a suitable inventory master for a store-led retail business.

Your POS may be the right choice if:

• Physical outlets generate most of your sales.
• Store employees receive stock through the POS.
• The POS tracks inventory by outlet.
• Your team records transfers and adjustments in the POS.
• Online and in-store sales use the same stock.
• Physical stock counts are performed in the POS.

The main advantage is speed. When a customer buys an item at the counter, the POS can immediately reduce the available quantity.

This matters when the same item is also listed on marketplaces and webstores. The latest POS quantity can be sent through Zetpy to those channels, reducing the risk of selling stock that is no longer available.

Option 2: Use Your Accounting Software as the Inventory Master

Accounting software can work as the inventory master for a smaller business with simple stock operations.

This setup may suit your business if:

• Purchasing is managed in the accounting system.
• Goods received are recorded there first.
• The finance or administration team controls stock adjustments.
• You operate a small number of outlets or warehouses.
• Your product and stock structure is straightforward.
• Sales transactions can be sent back to the accounting software reliably.

Keeping purchasing, inventory, and financial records in the same system can make reconciliation easier. Your team can compare stock movements with supplier purchases, sales, and other accounting records.

However, orders may take time to flow from a marketplace into the accounting system. During this gap, Zetpy can reduce the available online quantity as soon as the order arrives, while the accounting system processes the official deduction when it receives the order.

Option 3: Use Your ERP as the Inventory Master

An enterprise resource planning system, or ERP, is often the best inventory master for larger retailers and businesses with complex supply chains.

An ERP may be suitable if you manage:

• Multiple warehouses
• Several retail outlets
• Multiple business entities
• Wholesale and retail orders
• Complex purchasing processes
• Stock transfers between locations
• Product assembly or manufacturing
• Detailed approval processes
• High transaction volumes
• Centralized supply chain planning

An ERP can connect inventory with purchasing, warehouse operations, fulfilment, finance, and reporting. This makes it a logical source of truth when many departments affect stock.

ERP order-processing workflows can involve several steps. Zetpy can help protect the available online quantity while an online order is being transferred to and processed by the ERP.

How to Choose the Right Inventory Master System

Do not choose a system simply because it is the newest or most familiar. Choose the one that best represents what physically happens to your stock.

Ask the following questions.

1. Where are goods received?

The system that records incoming goods is often a strong candidate.

Your stock should not become available for sale until your team has physically received, checked, and confirmed it. The inventory master should reflect this process accurately.

2. Where are most sales recorded?

If most sales happen in retail outlets, your POS may be the most practical master.

If sales come from many sources and pass through warehouse or finance processes, your ERP or accounting system may be more suitable.

3. Which system understands every stock location?

Your inventory master should know where the stock is located. This may include:

• Retail outlets
• Main warehouses
• Regional warehouses
• Fulfilment centres
• Goods-in-transit locations
• Damaged-goods areas
• Return-processing areas

A single total quantity may not be enough if different channels sell from different locations.

4. Which system records every stock movement?

The master system should receive all events that increase or decrease inventory.

These include purchases, sales, transfers, returns, cancellations, damaged goods, and manual adjustments. If a system misses some of these events, it cannot maintain an accurate stock figure.

5. How quickly can the system update inventory?

The required speed depends on your sales volume.

A retailer that processes a few orders per day may manage with scheduled updates. A high-volume omnichannel retailer may need much faster synchronization.

Even with a well-connected master system, an online order may take time to transfer and process. Your inventory workflow should account for this timing gap so the same stock is not offered to another online customer while the first order is still moving to the master system.

6. Can it handle returns and cancellations correctly?

Inventory does not only decrease.

A cancelled order, returned item, rejected delivery, or failed payment may cause stock to become available again. Your master system needs clear rules for when that stock can be resold.

Returned items should not automatically become available if they still require inspection.

7. Which team owns inventory accuracy?

Technology alone cannot keep inventory accurate.

Your warehouse, retail, operations, or finance team must record stock movements correctly. Choose a system that the responsible team already uses and understands.

The business should also name an inventory owner who investigates differences and approves adjustments.

8. Can it connect with your sales channels?

Your inventory master must share stock information with the places where you sell. It also needs to receive orders from those channels so it can update the official quantity.

If direct integrations are limited, Zetpy can connect the master system with marketplaces and webstores while helping manage available online inventory during the order-sync process.

Rules That Prevent Conflicting Stock Updates

Choosing the right inventory master is only the first step. You also need clear rules for how systems and employees update stock.

Rule 1: Give One System Final Authority

Only the inventory master should decide the official stock quantity.

Zetpy can adjust the quantity available to connected online sales channels when an order arrives. The POS, accounting software, or ERP still remains the official source of truth and records the final inventory movement.

Rule 2: Define the Direction of Every Data Flow

Document where each type of information begins and where it goes.

For example:

• Inventory quantity: Master system → Zetpy → Sales channels
• Online orders: Sales channels → Zetpy → Master system
• Goods received: Purchasing process → Master system → Zetpy → Sales channels
• Stock adjustments: Authorized team → Master system → Zetpy → Sales channels

Avoid sending the same order or inventory update through several different routes. This can create update loops, delays, and conflicting figures.

Rule 3: Manage the Timing Gap for Online Orders

An online order may not appear in the inventory master immediately. It may need to pass through an integration and complete several processing steps first.

During this gap, the original quantity may still be available on other sales channels. This increases the risk of overselling, especially when stock is low or order volume is high.

With Zetpy, the available online quantity can be reduced as soon as the marketplace order is received. The updated quantity is then sent to the other connected online channels while the order continues to the master system.

When the master system receives the order, it records the official stock deduction. Zetpy is therefore protecting the online available quantity during the delay, while the master system remains responsible for the official inventory record.

Rule 4: Control Manual Inventory Changes

Employees should avoid changing quantities directly on individual marketplaces or webstores.

A manual change may be overwritten during the next synchronization. It can also create a difference that is difficult to investigate later.

Whenever possible, make the adjustment in the inventory master and let the updated figure flow through Zetpy to all connected channels.

If an emergency manual change is necessary, record who made it, why it was made, and how the master system will be corrected.

Rule 5: Prevent Duplicate Order Processing

A single sale should be recorded only once in the inventory master.

For example, if an online order passes through Zetpy before reaching the ERP, the ERP should not receive the same order again through another connection. Otherwise, the master system may deduct the same sale twice.

Use one defined order route and a unique order reference to prevent duplicate processing.

How Zetpy Connects Your Inventory Master With Sales Channels

Your POS, accounting software, or ERP should remain the inventory master. Zetpy connects that system with your marketplaces and webstores while helping manage the timing gap between an online sale and the final update in the master system.

A typical workflow may look like this:

1. Your POS, accounting software, or ERP holds the official stock figure.
2. Zetpy receives the inventory information and sends the available quantity to your connected marketplaces and webstores.
3. A customer places an order through one of those online channels.
4. Zetpy receives the order and immediately reduces the quantity available across the connected online channels.
5. The order flows through Zetpy to the inventory master.
6. The master system processes the order and records the official stock deduction.
7. The latest master quantity flows through Zetpy to the connected sales channels.

For example, the master system and connected online channels show 20 units. A marketplace order arrives for one unit. Zetpy reduces the available online quantity to 19 and shares that quantity with the other connected online channels.

The master system may still show 20 units while the order is being transferred. Once it receives and processes the order, its official figure also becomes 19. That latest master figure is then synchronized through Zetpy.

This two-stage process does not deduct the same unit twice. It serves two different purposes:

• Zetpy protects the available online quantity as soon as the order arrives.
• The master system records the official stock movement when it processes the order.

This helps reduce the chance of another online customer buying the same unit during the synchronization delay. It also allows the POS, accounting software, or ERP to remain the official inventory master.

Depending on your setup and available integrations, Zetpy can help your team:

• Reduce manual inventory updates
• Lower the risk of overselling during order-sync delays
• Keep marketplace and webstore quantities aligned
• Connect online orders with retail or back-office operations
• Process marketplace and webstore orders more efficiently
• Maintain clear responsibilities between systems
• Spend less time correcting stock differences

The exact workflow depends on your software, sales channels, locations, and operating rules. Map the complete process before activating automated inventory updates.

Final Recommendation

Your inventory master should be the POS, accounting software, or ERP system that most accurately reflects the physical movement of your stock.

Choose your POS if your operations are mainly led by retail outlets. Consider your accounting software if your inventory process is straightforward and closely connected to purchasing and finance. Choose an ERP if you manage complex warehouses, locations, supply chains, or transaction volumes.

Marketplaces and webstores should receive inventory from the chosen master. They should not control the official stock figure.

At the same time, your workflow must account for the delay between receiving an online order and recording it in the master system. Zetpy can reduce the available online inventory as soon as an order arrives, then send the order to the master system for the official deduction.

Whichever system you select, follow four basic principles:

• Maintain one official source of inventory.
• Define clear directions for every update.
• Reduce available online stock as soon as an order is received.
• Send every sale back to the master system for official processing.

Zetpy can help connect your chosen inventory master with marketplaces and webstores, creating a clearer and more responsive omnichannel inventory workflow.

Want to connect your POS, accounting software, or ERP with your online sales channels? Book a demo with Zetpy to discuss an inventory workflow that fits your business.

1:21 PM