Key Takeaways:
- An eCommerce POS integration links two separate systems: your online store and your point of sale. Most problems happen when both systems try to control the same information.
- “Real-time sync” often means the systems check for updates on a schedule. Ask how many minutes pass between a sale in your store and a stock update on your website.
- Many problems are not sync problems at all. They come from products set up differently in each system, product codes that do not match, and tax rules that differ between the store and the website.
- Decide which system controls each type of information before you connect anything. Changing that later means redoing your product setup.
When you connect your online store to your point of sale, you link two systems, and each keeps its own record of what you have in stock. When the link works, one product list and one stock count serve both the store and the website. When it doesn’t, your website sells an item you sold in the store an hour ago.
The shared stock is what makes the setup tricky. This guide covers what gets synced, how timing works, the seven setup problems that cause the most trouble, and what to ask a vendor before you sign.
What Kinds of Information Does a POS Sync?
An integration moves five kinds of information between your website and your POS, each in a different direction. Decide which system controls each kind of information before you connect anything. The table below covers what information moves where in your eCommerce POS sync.
| Information | Which system should control it | Direction | What happens if both control it |
|---|---|---|---|
| Product list | Usually the POS back office, so both places show the same product details | POS to website | Staff change a product on the website, the next sync overwrites it, and the change is gone |
| Stock counts | The POS, because it records deliveries, counts, losses, and returns | POS to website | Both systems subtract stock and neither count is correct |
| Orders | The website takes them, the POS records them as sales | Website to POS | Online sales never reach your sales reports, so your numbers look wrong |
| Customers and loyalty | One shared record, in whichever system holds the points balance | Two-way | The same customer exists twice and earns points in only one place |
| Prices and promotions | The POS, unless you charge different prices online on purpose | POS to website | A promotion rings up at one price in the store and another online |
How Often Stock Syncs Between Your POS and Your Website
Most vendors say the sync is real-time, but you should ask how many seconds or minutes it takes. Some systems send an update as soon as a sale finishes. Others check for changes on a schedule, such as every 10 or 15 minutes, which is common in plugin-based setups.
That interval matters because it is how long your website can keep selling something you no longer have in stock. Ten minutes on a busy Saturday is enough to sell your last few units twice.
Three Ways to Stop Your Website From Overselling
- Show fewer units online than you have. Subtract a small reserve, and make it larger for fast sellers.
- Hide low-stock items. Set a cutoff instead of listing single units.
- Show exact counts only on slow sellers. For items that sell a few times a year, the real number is safe and useful.
Seven Setup Problems That Break eCommerce POS Integrations
Sync timing is only part of the equation. Most problems come from setting up the same product differently in the two systems. Check these seven before you launch:
Multipacks and case breaks that share stock with single units
If you sell single cans in the store and four-packs online, both come out of the same stock, and the integration has to know that one online order removes four units. If it does not, your counts are wrong every day.
Set up the multipack as one product made from four single items, not as a separate product with its own count. KORONA Studio has a sub-product function for this, so a multipack listing pulls from the same stock as the singles.
Barcodes that do not match your website product options
Websites usually organize products by option, such as size or color. POS systems organize by barcode. A shirt in three sizes is one product with three options online and three separate items with three barcodes at the register.
Match them up before launch and use the same code as the link on both sides. Our SKU management guide explains how to set up codes that support this.
Prices and promotions that differ between the store and the website
If both systems can set prices, they could eventually show different prices, usually during a promotion. Decide whether the POS sends prices to the website or the two are priced separately, and write it down.
If you sell alcohol or tobacco, check your state’s minimum price and markup rules before running an online discount. Those rules apply across all channels.
Sales tax charged at your store rate instead of the delivery rate
Sales in your store use your store’s tax rate. Shipped orders usually use the tax rate where the order is delivered, so your integration has to calculate tax by delivery address and report it separately.
Ask how the integration does this. Also ask what happens once you ship to other states, because most states require you to collect their tax after your sales there pass a certain amount. Plugin-based setups often miss this.
Bottle deposits and bag fees folded into the product price
Container deposits, bag fees, and environmental fees are separate charges with their own tax treatment, and many integrations fold them into the product price. In Michigan, a ten-cent bottle deposit that syncs wrong leaves a small difference on every order and a mess to sort out at month end.
Place one test order for a deposit item and check that the deposit shows as its own line in both the website order and the POS record.
Refunds on online orders returned in your store
A customer who buys online and returns the item in your store creates a refund with room for error. Some systems handle this in one step; some need a manual refund through the payment gateway; and some cannot refund part of an online order at all.
Ask the vendor to show you this exact situation during the demo instead of reading it off a feature list. Our returns guide covers the policy side.
Age verification and shipping limits on restricted products
At the register, age verification means a person checking an ID. Online, it means a check at checkout and another at pickup or delivery, and the requirements vary by product and by state.
Shipping is the bigger limit. Alcohol shipped straight to customers is restricted by state and license type, most nicotine and vape products face federal shipping restrictions, and cannabis is limited to state-licensed delivery. For most specialty retailers, that means online ordering with in-store pickup instead of shipping.
Free printable templates and checklists to help you manage retail operations with ease
Buy Online, Pick Up in Store: When To Subtract the Stock
You have to decide when a unit stops counting as available: when the customer places the order, or when they pick it up.
Subtracting at order time protects the online customer, but it can show an item as sold out while it is still sitting on the shelf. You can also mark the unit as reserved instead of sold. If you do that, set a time limit so orders nobody picks up go back to available stock after a few days.
Offline Mode: What Happens to Stock When Your Internet Goes Down
A cloud-based POS in offline mode keeps ringing up sales on the terminal, your website keeps taking orders, and neither one knows what the other did.
When the connection returns, the stored sales sync, and you may find you sold the same units twice. Ask how the system stores offline sales, how long it can run without a connection, and what happens to stock counts while it catches up.
Keeping Online Orders Separate in Your End-of-Day Totals
Online payments go to your payment gateway rather than your register. If you add online orders to the same register total as your drawer, your end-of-day count will not balance.
Set online orders to post to their own register or sales channel from the start. KORONA Studio reports by channel and location, so you can see whether an item that sits on the shelf is actually selling online.
Troubleshooting an eCommerce POS Integration
Most complaints come back to a short list of causes. This table covers what retailers report most often.
| Problem | Likely cause | What to check |
|---|---|---|
| Website sold an item you do not have | Sync interval too long, or no reserve set on the website | Confirm the actual interval, then set a cutoff to hide low-stock items |
| Stock counts drift a little every day | Multipacks or case breaks set up as separate products | Rebuild multipacks as one product made from the single item |
| A product change on the website keeps reverting | Both systems are set to control the product list | Pick one and set the other to read-only |
| Online orders missing from sales reports | Orders sync as orders but never post as sales | Check whether online orders post to a register or sales channel |
| Tax collected online does not match filings | The integration is using your store’s rate instead of the delivery address rate | Test an out-of-area shipping address and compare the tax charged |
| Refund on an online order fails at the register | No card at the counter and no matching sale in the register | Ask the vendor for the documented steps for this refund |
| Duplicate customers and split loyalty points | No shared field linking customer records | Match on email or phone and merge the duplicates |
| Everything oversold after an outage | Offline sales stored on the terminal and synced late | Review how offline mode works and how stock catches up |
Pre-Launch Checklist for an eCommerce POS Integration
Work through this list before you take a live online order. Each item matches a problem above.
- One system named as the controller of the product list, stock counts, and prices, in writing
- Sync interval confirmed in minutes, not described as real time
- Product codes matched between systems, with the same code linking them
- Multipacks and case breaks built as one product made from the single item
- A low-stock cutoff or reserve set for the website
- One test order placed and filled for a deposit item, a multipack, and an age-restricted item
- Tax tested with an out-of-state shipping address
- A refund tested from start to finish, including a partial refund
- Online orders posting to their own register or sales channel
- A time limit set on pickup orders, with a rule for orders nobody collects
- Offline mode tested by disconnecting a terminal during a sale
What an eCommerce POS Integration Costs
The subscription is the smallest part of the total. The cost most retailers miss is keeping a website running that now depends on a plugin, a theme, and a POS connector all working together.
| Cost | Typical range | What people forget |
|---|---|---|
| POS subscription | $50 to $300 per month for a small store, more with several locations | Pricing per terminal and per location rather than one flat fee |
| Website platform or hosting | $0 to $100 per month, more on managed hosting | Plugin and theme licenses that renew every year |
| Integration or connector | Included, or $20 to $150 per month for a third-party connector | Price tiers that go up as your order volume grows |
| Payment processing | About 2.5% to 3.5% per transaction | Online rates are usually higher than in-store rates |
| Hardware | $500 to $2,000 one time | The website needs none, but a printer for pick lists helps |
| Setup and data transfer | $0 to $1,500 one time | Cleaning up your product data, which is usually the real work |
| Ongoing maintenance | Varies | Someone has to handle plugin updates and test the sync afterward |
Questions To Ask a POS Vendor Before You Sign
A feature list will not tell you how the sync behaves. These questions will.
- What is the actual sync interval for stock, in seconds or minutes?
- Does stock sync one way or both ways, and which system wins if they disagree?
- How do you handle a multipack that shares stock with single units?
- Show me a customer buying online and returning the item in the store, including a partial refund.
- Does the integration calculate tax by delivery address?
- What happens to online orders and stock counts when a terminal goes offline?
- Can online orders post to a separate register or sales channel for reporting?
- Do you build and support the integration, or does a third party?
- What does it cost at ten times my current order volume?
How KORONA POS Handles the Connection
KORONA POS runs its eCommerce integration through WooCommerce. The product list, stock, and prices are managed in the KORONA Studio back office, so you don’t have to keep them up to date twice. Age verification can be required at checkout, and multi-location stores can show stock by location so customers see what is on the nearest shelf.
For the problems above, the two features that matter most are sub-products for multipacks and case breaks, and reporting by sales channel so online orders stay separate from your drawer. A demo is the fastest way to see how it would handle your product mix.
Frequently Asked Questions
What is eCommerce POS integration?
It is a link between your online store and your point of sale so both use the same product list and the same stock count. The website handles the storefront and checkout, the POS keeps the record of what you have and what you sold, and the integration keeps the two matched up.
Does POS stock really sync in real time?
Often not. Some systems send an update the moment a sale finishes, but many check for changes on a schedule of a few minutes, so ask for the actual number instead of accepting the phrase.
Do I need a POS system to sell online?
No. A website platform can take orders and payments on its own. You need the integration when the same stock serves both the store and the website and you want one stock count, one product list, and one set of sales reports.
Which system should control my stock count?
The POS, in nearly every case. It records deliveries, physical counts, losses, and in-store returns, so it has information the website never sees.
Can I sell alcohol or vape products through an integrated online store?
Online ordering with in-store pickup usually works. Shipping is where the limits are: alcohol shipped to customers depends on your state and license, nicotine and vape products face federal shipping restrictions, and cannabis is limited to state-licensed delivery.
How long does an eCommerce POS integration take to set up?
The connection itself can be quick. The work is cleaning up and matching your product data, and for a store with a few thousand items that usually takes weeks rather than days.
