Unified Commerce — is modern e-commerce ready for the new omnichannel?

The problem of traditional omnichannel

In the world of modern e-commerce, technology is speeding faster than ever. Other sales channels, marketplaces, social commerce and deferred payments appear almost overnight. However, under the hood of many trading companies, one can still find a “digital frankenstein” — an architecture made up of many mismatched systems, that are trying to talk to each other using outdated integrations. Effect? The tech industry offers incredible opportunities, but the operational infrastructure of many companies has simply stopped keeping up with them. This disconnect between business ambition and system reality is best seen at the moment when real-time data collides.

Imagine this situation: you have the last piece of a limited product. In the same second, a customer in Berlin clicks “Buy now” on your website, and a customer in a stationary store in Warsaw just walks up with the same box at the checkout. The systems “see” each other every 15 minutes. By delay in data synchronization there may be a situation where both customers have paid, but there is only one product. Such a phenomenon is called a warehouse lag. Unfortunately, in the world of traditional Omnichannel, data is scattered — ERP has its own base, an online store its own, and marketplaces such as eBay or Amazon have yet another. “Bridges” between them (i.e. integrations) rarely work in real time which leads problems.

AI won't wait for data synchronization

The situation becomes critical when our omnichannel reaches Agentic Commerce. AI agents, which we wrote about in the previous article, operate in time counted in milliseconds or seconds. If you “send an agent shopping,” it must be 100% sure that the product it sees actually physically exists. An agent should not rely on repeatedly refreshing the ecommerce platform — it needs a reliable source of transaction data — “hard” data here and now.

Why do ecommerce systems “lie” about inventory?

In computing, there is a foundation of secure transactions called ACID (Atomicity, Consistency, Isolation, Durability). Although it sounds like the name of a rock band from the 80s, it is a rule as old as the world: the transaction will either happen in full (the money disappears and the goods are reserved at the base) or not at all.

In e-commerce, we have a huge problem with this. The problem is not with individual systems (which are usually ACID), but transactions stretched across multiple channels and integrations — that's where ultimate consistency prevails, that is, the data “gets along”... in a while. As long as you sell 10 packs of coffee a day, that's not a problem. But on a large scale, this lack of a common checkpoint of all channels (places that “close” access to the merchandise at the time of purchase) generates errors, return costs and frustration for the service and, above all, the customer.

Battle for the standard: Booking instead of asking

Just asking the API about whether a product is in stock is no longer enough in the coming years. By the time the answer “yes, we have it” reaches the customer, the goods may be gone. However, the solution to this problem could be a unified commerce strategy, both Google and OpenAI, already promote protocols that introduce a mechanism for booking on the fly (soft-locking). This is an attempt to technically “freeze” the commodity at the moment when the transaction is just beginning.

Universal Commerce Protocol (UCP) — The Vision of Google and Shopify

This direction of development, is to make your warehouse “transparent” to the Google ecosystem. A store using UCP not only displays a list of products, but allows Google algorithms (such as Gemini) to see stock levels in near real-time.

How does it fight the warehouse lag? UCP assumes that the moment Google Assistant offers you to buy a particular drill, it sends a signal to your system: “Hold this piece for 60 seconds, because the customer is looking at it. This is a short reservation that gives the system time to finalize without the risk that someone else will buy the goods in the meantime. It's a visibility and accessibility protocol.

Agentic Commerce Protocol (ACP) — OpenAI and Stripe Vision

Here the emphasis is on the action itself and the payment. OpenAI, working with Stripe, wants the transaction to be as close as possible to the IT ideal of ACID — that is, indivisible.

How does it fight lag? In ACP, it is the transaction processor (Stripe) that becomes the main arbiter. When ChatGPT says “I buy,” the ACP protocol takes a swipe at your system that combines two steps into one: payment authorization with instant removal of goods from the warehouse. If your system doesn't confirm your booking in a split second, Stripe won't charge you. So you avoid a situation where you have money, but you have nothing to send. This is a protocol of actions and settlements.

Comparison of two visions of the e-commerce world

However, it is worth remembering that although giants such as Google and OpenAI impose the pace, Universal Commerce Protocol (UCP) and Agentic Commerce Protocol (ACP) are standards that will continue to evolve dynamically in 2026. Their implementation is not only a matter of “plugging in”, but above all, of the API readiness of your sales channels to handle queries in milliseconds. The standard itself is just a language of communication — in order for systems to “speak one language” your infrastructure must first be able to generate precise state data in real time before the AI agent even asks for it.

But we have to get down to earth: Even the most advanced communication protocol will not fix the problem if the foundations of your internal data architecture are unstable. UCP or ACP standards are merely “languages” by which systems communicate with the outside world. However, if the sender of the message does not have full, real control over what is happening in his own systems, then the external AI agent will simply receive very precise, but... erroneous information.

Standard is not everything when the foundations do not keep it up

The problem arises when your internal systems are unable to maintain the aforementioned data consistency. Let's imagine the situation: your online store claims to have 5 pieces of a particular model of a food processor in stock. However, at the same time, your warehouse system (WMS) knows that physically there is only one piece left, because the other four are already waiting to be packed after yesterday's promotion in the offline store, but this information has not yet been “submitted higher”.

In such a scenario:

1. A Google Agent (UCP) queries the store and sees 5 available pieces.
2. It imposes a “booking” on one of them, giving the customer the green light to purchase.
3. The customer pays, and you get yourself into an oversale because you sold a product that was physically no longer on the shelf at the time of booking.

In this case, it was not the protocols that failed, but the internal synchronization of the data. If ERP, WMS and e-commerce platform do not work on the same, instantly updated dataset, then even the most modern standards from Google or OpenAI will only powder the technological debt.

And the situation gets even more complicated if you add sales through marketplaces to this already difficult puzzle. Ebay or Amazon are powerful but isolated islands. They have their own databases, their own delays in refreshing states, and — worst of all — they have no interest in your internal order in the data. When a sale comes through a marketplace, the information about it has to “flow” through a series of integrations before your store (and eventual AI agent) learns that the merchandise has just disappeared. This is where Unified Commerce collides with the harshest reality: how to maintain a single truth about the state of a product when orders flow from five different, independent directions?

Implementing Unified Commerce as a Solution

Now that we know that protocols alone will not fix the mess in the data, we are faced with a key question: how do we technically regain control of inventory so as not to disappoint the customer? The industry is currently following the two main strategies of Unified Commerce, which we will describe in the following paragraphs.

First Strategy — The Shopify Approach

Shopify promotes a vision that can be called a “digital monolith.” Their idea of implementing Unified Commerce is radically simple: since the synchronization of multiple systems generates delays, then... let's stop using multiple systems. In this model, your online store, payment terminals in stationary stores (POS) and even the basic warehouse operate on the same, single database. Such uniformity means that when a salesperson in the showroom scans a product, the stock in the online store changes in exactly the same microsecond.

What is the threat of this type of Unified Commerce strategy? Full migration to a single ecosystem is a classic vendor lock-in – a situation in which your business becomes completely hostage to a single software provider. If in two years the platform drastically increases the subscription fee or commissions on each transaction, your e-commerce may not have a simple way out of the situation.

Polish e-commerce industry perfectly remembers the “Baselinker lesson” — sudden and drastic changes in the price list of the e-commerce management system, have made many retailers aware of how painful it can be to depend on one key link that cannot be easily replaced. In a monolithic model, this risk is even greater: moving the entire ecosystem (payments, balances, sales) is an open-heart operation that many companies may not survive.

Second Strategy — BPA (Business Process Automation) Approach

If you value independence and do not want to put the reins of your company in the hands of one giant, the solution is smart Business Process Automation (BPA). Instead of relying on systems to get along on their own, to achieve unified commerce, you can build a “control layer” over them — on-call traffic that manages access to goods in a multichannel distribution (e.g., using n8n in conjunction with dedicated data layers and system queues).

In computer science, we use the concept of critical section to define this type of supervision. The idea is to create a moment in the process where only one system at a time can reserve a given product. What does it look like in practice? To achieve full control over the channels, mechanisms called mutexes or semaphores are used in Unified Commerce:

• The mechanism of the “Red Flag” (Mutex): imagine that there is a virtual red flag standing next to each product in the warehouse. When a customer on eBay begins the checkout process, your automated assistant (BPA) raises the flag. At this point, the online store and the terminal in the salon see: “Stop, flag up, you can not sell this piece, verification is in progress.” Only when the customer completes the payment (or it is rejected) does the flag go down.
• “Ticket” mechanism (Semaphore): This system is like taking a number in a queue. If you have 5 pieces of goods, the BPA system issues 5 “entrance tickets” for purchase. Any sales channel (e-commerce platform, Amazon, AI assistant) must first request a ticket. If the tickets run out, the systems automatically show the potential customer “no goods”, even if their local bases don't know about it yet.

The “soft-locking” mechanism is a powerful tool in the fight against lag, but requires surgical precision in configuration. While freezing goods for 60 seconds gives the customer valuable time to complete the payment, with the huge scale of inquiries from hundreds of AI agents, the phenomenon of “artificial lack of goods” can occur. If too many processes raise the “red flag” at the same time, the systems may show a lack of availability even though the real transactions have not yet been closed. The key to success in the BPA model is to intelligently manage the duration of such a flag to balance between consistent information for buyers and maximum exposure of the offer in sales channels.

The choice of Unified Commerce strategy is yours

In technology, as in business, there are rarely solutions that are perfect for everyone. Choosing between a monolithic model (like Shopify) and process orchestration (BPA) is a classic compromise game. There is no perfect solution here that will answer all your problems without any side costs.

• Shopify Strategy – this is a faster and cheaper solution to implement. You get a ready-made, proven infrastructure that “just works”. This is an ideal choice for companies that want to move to a higher level of data consistency in no time and accept that by providing customers with a consistent shopping experience, they will also hand over a large part of the control of their e-commerce to a third-party provider.
• BPA Strategy (e.g. n8n, own microservices) – is an investment that is more expensive and requires more time to start. Building a dedicated “on-call traffic” that will dominate your unique systems requires precise logic design and testing. In return, however, you get full business independence and an architecture that grows with you, without being susceptible to sudden changes in the pricing policy of external platforms.

The choice depends on your strategy: do you prefer to pay for a “ready ticket” and go the designated route, or do you prefer to build your own vehicle that will get you exactly where you want, on your own terms?

Not sure which omnichannel and Unified Commerce strategy to choose? We will help you make a decision

We realize that from the perspective of a business owner or e-commerce manager, these technological dilemmas can be overwhelming. At Sagiton, we don't sell “the only right method.” Our role is to guide you through this process safely:

1. We analyze your case: we look at your current systems (ERP, WMS, marketplaces) and the real problems you face.
2. We advise: we honestly assess whether a quick migration to a single platform or building a BPA automation layer that connects all channels will work better in your situation.
3. We implement: if you decide on one of the options, we take on the technological side, making sure that the systems in communication with customers finally begin to speak with one voice.