E-commerce: how does architecture manipulate your prices?

What you don’t see when you compare prices online

A client called us a few months ago. He had just discovered that a product he’d bought on a major marketplace was displayed 23% cheaper on the manufacturer’s website — after clicking a “best price” link promoted by the platform itself. He wasn’t angry. He was confused. “How is that possible?”

It’s possible because the information architecture on these platforms is not neutral. It has never been neutral.

The recent accusations against Amazon — price manipulation, misleading presentation of offers, opaque “Buy Box” system — come as no surprise to anyone who has worked in e-commerce development for more than ten years. What is surprising is how long it took for the subject to come fully into the spotlight.

Because at its core, the question is not “is Amazon honest?” The real question is: how can information architecture be designed to manipulate without lying?

What is information architecture, concretely?

When you open a product page on a marketplace, you are looking at a staged scene. Not a neutral catalogue.

The visual hierarchy — what is large, what is small, what is in red, what is crossed out — is the result of thousands of design decisions. Each decision influences your behaviour. And when those decisions are made by a platform that itself sells products in competition with its own third-party merchants, the conflict of interest is structural.

Here is how it works in practice.

The strikethrough price as an illusion of reference

Displaying a crossed-out “before” price next to the current price creates a cognitive anchor. The brain automatically calculates a saving. But where does that reference price come from? On Amazon, it may be the highest price charged by any seller on the platform — even for a single day, even on a token quantity.

The US Federal Trade Commission (FTC) has documented these practices in its investigations. In Europe, the DGCCRF (France’s consumer protection authority) carries out similar audits. The Omnibus Directive, which came into force in France in May 2022, now requires that the reference price be the lowest price charged in the previous 30 days. But enforcement remains complex to verify at the scale of a marketplace of this size.

The Buy Box: the choice you think you’re making

The Buy Box is that “Add to cart” button displayed on the product page. When several sellers offer the same item, Amazon decides which one appears by default in that box.

The algorithm governing this choice is opaque. Price, delivery time, stock, seller performance history — all of these factors play a role. But Amazon Retail, the branch that sells directly, benefits from a structural advantage in this algorithm. Independent studies — notably one published by the Institute for Local Self-Reliance — have shown that Amazon awards itself the Buy Box even when third-party sellers offer lower prices.

The result: you think you are making a choice. In reality, the choice has been made for you. This is precisely why conversion optimisation on your online store starts with taking back control of your interface — not copying the mechanics of the giants.

Why this is an architecture problem, not just bad faith

It would be easy to reduce this to “Amazon is a bad company”. That would miss the real point.

These practices exist because information architecture enables them — and because the AI systems that power these platforms are trained on conversion objectives, not fairness.

A recommendation algorithm optimised to maximise revenue per visit will naturally favour offers that generate the most margin for the platform. If nobody explicitly tells it “treat all sellers fairly”, it won’t. This is not malice. It is optimisation without ethical constraint.

“AI systems amplify the biases they are given. If the objective is platform profit, AI optimises platform profit — not user wellbeing.”

This is precisely what European regulators have begun to address with the Digital Markets Act (DMA), which came into force in 2023. “Gatekeepers” — of which Amazon is one — are now subject to non-discrimination obligations between their own services and those of third parties. Concrete enforcement is another matter.

What this means for your online store

If you manage an e-commerce site, this discussion is not abstract. It directly affects your strategy.

Selling on a marketplace means playing in a stadium where the rules change without notice. The visibility you buy today can disappear tomorrow if the algorithm is updated. Your price can be undercut by the platform itself on your own products. Your Buy Box can be lost to a competitor you don’t even see.

What we consistently observe with our clients who sell on Amazon or similar marketplaces: dependency sets in quickly. The channel generates volume. Then conditions change. Commissions increase. Organic visibility shrinks. And the brand has built no direct relationship with its customers.

The solution is not to flee marketplaces. They remain powerful acquisition channels, especially for new product discovery. The solution is not to make them your only channel.

Building your own point of sale means taking back control of the architecture

When you have your own online store — PrestaShop, WooCommerce, or a custom e-commerce site — you decide the information architecture. You choose how to display your prices, which products to highlight, what shopping experience to offer.

You do not depend on an opaque algorithm to decide whether your product deserves to be visible.

Good architecture practices that protect your customers — and your credibility

Whether you are building your store from scratch or auditing an existing one, here is what distinguishes honest architecture from manipulative architecture.

Transparency of reference prices

If you display a strikethrough price, the reference price must be real and verifiable. The Omnibus Directive makes this a legal requirement. But beyond compliance, it is a matter of trust. A customer who feels manipulated does not come back.

Visual hierarchy in the user’s interest

What should be highlighted: the actual price, delivery conditions, essential product information. What must not be misleadingly highlighted: “savings” calculated on artificial reference prices, “bestseller” badges with no clear criteria, fake countdown urgency timers.

Clarity on sellers and offers

If you operate a marketplace or a multi-seller site, the seller’s identity and the conditions of each offer must be immediately readable. The user must know who they are buying from before clicking.

Accessibility of comparison information

A user who wants to compare offers should not have to search. Comparison information — unit price, total cost with delivery, availability — must be accessible at a glance.

“Good e-commerce architecture does not hide information. It structures it so that the purchasing decision is informed.”

What developers and designers need to take away

If you design e-commerce interfaces — whether for your agency, your client, or your own SaaS — these practices concern you directly.

Pricing dark patterns are not reserved for giants. Modestly-sized PrestaShop stores reproduce the same mechanics: artificial strikethrough prices, fake urgency, misleading prominence for certain offers. Often by mimicry, sometimes through ignorance of the legal implications.

Since the Omnibus Directive, the DGCCRF has the tools to sanction these practices — including for mid-sized players. Fines can reach 4% of annual global turnover. This is no longer a theoretical risk.

My advice for an SME with a limited budget: before optimising your conversion rate with artificial urgency techniques, invest in clarity. A clear price, a readable returns policy, an honest delivery time — these convert better in the long run than an invented countdown.

The figures from our audits confirm it: sites that simplified their pricing architecture saw their cart abandonment rate fall by 15 to 30% — a trend also confirmed by the analysis of major UX e-commerce trends in 2026. Complexity does not reassure. It drives customers away.

Three takeaways for your e-commerce strategy

1. Information architecture is a tool of power. On major platforms, it is designed to maximise the platform’s revenue — not your satisfaction as a buyer, nor your visibility as a seller. Understanding this is the first step to not being at its mercy.

2. Your own online store is your only sovereign digital asset. Marketplaces are acquisition channels, not foundations. Building your own e-commerce presence — with a transparent architecture and an honest user experience — means building something that belongs to you.

3. Transparency is a competitive advantage, not a constraint. At a time when consumers are increasingly wary of online pricing practices, a store that plays fair stands out. Trust is built slowly. It is lost in a single bad experience.

Your online store deserves an architecture that works for you

The accusations against Amazon will not go away. European regulators continue to tighten the net. And consumers are learning to read interfaces — to recognise suspicious strikethrough prices, artificial urgency, pre-made choices.

In this context, the question you need to ask yourself is not “how do we do it like the big platforms?” It is: “how do we build a store where our customers feel respected?”

At GDM-Pixel, we support French SMEs and merchants who want to sell online without resorting to manipulation. We audit existing architectures, build PrestaShop and WooCommerce stores with clear pricing structures, and automate what can be automated — without sacrificing transparency.

If your current store relies on questionable mechanics inherited from a poorly configured template, or if you want to launch your e-commerce business on solid foundations, let’s take the time to talk. A 3-day audit is worth more than a regulatory fine or a cart abandonment rate that kills your ROI.

Honest architecture is built. And it is measured.