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Competitor price analysis for an online store
Competitor price analysis for an online store: what to compare, which rules to write down and what the law limits. A ShopGuru guide. Book a call.
In an online store, competitor analysis is usually done by hand: ten tabs open, prices copied into a spreadsheet and a whole morning with no decision at the end. At ShopGuru, competitor price analysis is the agent's job: it compares and proposes, and the store's team decides the price. Here is what to compare, the rules to write down before looking at the numbers and the limits Portuguese law puts on dynamic pricing.
Article summary
- Competitor price analysis for an online store compares the final price of the same products in other stores, including shipping and availability.
- The store's pricing rules, such as the minimum margin, the maximum drop and the rounding, are written down before any comparison.
- In Portugal, an advertised price reduction has to show the lowest price applied in the previous 30 days, which limits dynamic prices that go up and down often.
- Selling below the effective purchase price is, as a rule, prohibited in Portugal, even when a competitor sells for less.
- The ShopGuru agent tracks the competitors your team chooses and prepares suggested prices with the reasoning, without applying them.
- A suggested price only changes in the store after someone on your team approves it, logged with a name and a time.
- A 30-minute call with a ShopGuru engineer is enough to work out which of your products are worth tracking.
Why comparing prices by hand isn't enough
A morning spent comparing prices solves that morning's problem. The following week, some of the figures have already changed, and the spreadsheet is out of date before anyone decides anything.
Worse than the time is comparing badly: a competitor's shelf price without shipping, an out-of-stock product that looks cheap, a marketplace set beside a standalone store.
Price monitoring is far from rare. In a survey of 38 companies selling online in Portugal, about 37% said they used software that automatically monitors competitors' prices, according to the Portuguese Competition Authority's report on digital ecosystems, big data and algorithms (in Portuguese), from July 2019. Only 7.9% used software that sets prices automatically.
"Comparing a shelf price without shipping is comparing your store with a store that doesn't exist." ShopGuru
What to compare in a competitor price analysis
For pricing purposes, a competitor is a store that sells the same reference, or an equivalent one, to the people who also buy from you. Large marketplaces go in a separate column, because their fees, delivery times and returns are different.
The products that matter are branded ones, with the same reference in several stores, which customers compare before buying. A good starting point is your best sellers and the products that come up most in customer questions: when someone asks customer service in your online store whether you'll match another store's price, that question is data too.
| What goes into the comparison | Why |
|---|---|
| Product price | It's the starting point, not the conclusion |
| Shipping for the store's typical customer | A lower price with €4.95 shipping can end up dearer |
| Availability | An out-of-stock product competes with nobody |
| Date checked | A price read a week ago may no longer exist |
The pricing rules a store writes down before comparing
Our position: the store doesn't need the lowest price on the market. It needs to know, product by product, how far it is willing to go and why. These rules are written before the comparison, so that a competitor's number doesn't decide for the store.
- Minimum margin: no suggested price goes below it.
- Maximum drop: how far a price can fall in one go.
- Rounding: if the store's prices end in .90, so does the suggested price.
- A gap worth looking at: the team agrees from what difference it's worth taking a look, for example 5%.
"The store doesn't need the lowest price on the market. It needs to know how far it will go, and why." ShopGuru
Dynamic pricing and the law: what limits a price in Portugal
Dynamic prices are prices that change often in response to the market, frequently through software and without a person deciding each change. The ShopGuru agent doesn't work that way: what it produces is a suggested price, which only changes in the store once approved. In a Portuguese store, any way of moving prices runs into several rules.
The 30-day rule for price reductions
Since 28 May 2022, anyone who advertises a price reduction has to show the lowest price applied in the previous 30 consecutive days. The rule is in Decree-Law No. 70/2007 (in Portuguese), as amended by Decree-Law No. 109-G/2021, and it also applies to distance sales. It comes from Directive (EU) 2019/2161, known as the Omnibus Directive.
The law defines that price as the lowest price at which the product was sold in the 30 days before the reduction. In practice, if a product is actually sold for less for three days to follow a competitor, that figure is likely to become the reference for a promotion advertised in the following 30 days. A store that moves prices often has less room to advertise discounts later.
Selling below cost to follow a competitor
Decree-Law No. 166/2013 (in Portuguese) prohibits selling goods below their effective purchase price, plus the applicable taxes and, where relevant, transport costs. Article 5 lists four exceptions: perishable goods at risk of rapid deterioration, goods whose commercial value is impaired, goods the store restocks at a lower price, and sales or clearances. Following a competitor's price isn't among them. For a specific product in doubt, the final word belongs to a lawyer.
Personalised prices and prices that react to the market
The same directive added a requirement for the store to tell customers when a price has been personalised on the basis of automated decision-making, for example from their purchase profile. Recital 45 of the directive excludes from that notice dynamic pricing that reacts to the market without personalising the price.
Tracking prices is legal; colluding isn't
In its 2019 report, the Competition Authority points out that companies are responsible for the algorithms they use. Using these tools to coordinate prices between competitors, including by outsourcing pricing algorithms to common providers, is not compatible with competition law. With ShopGuru, the pricing decision belongs to each store's team, and every approval is logged with a name and a time.
"A price that moves on its own still leaves a trail: in the margin, in the next promotion and in the law." ShopGuru
How the ShopGuru agent prepares a suggested price
The agent tracks the stores your team chooses, compares the final price, shipping included, and proposes a suggested price within the store's margin rules. It leaves it in the app as a proposal, with the reasoning on view. While the proposal waits, the store keeps selling at the current price.
Fictional example. In a cycling accessories store, the Trilho helmet costs €64.90, with free shipping. The team chose three competitors to track for this model and agreed that only gaps above 5% are worth a look. On Tuesday 13 October, this proposal comes in:
| Store | Price | Shipping | Total | Agent's note |
|---|---|---|---|---|
| The store (current) | €64.90 | free | €64.90 | |
| Competitor A | €57.90 | €3.90 | €61.80 | |
| Competitor B | €59.00 | free | €59.00 | €5.90 below the store |
| Competitor C | €54.90 | €4.50 | €59.40 | Out of stock for 6 days, left out |
The suggested price is €59.90: a 7.7% drop, within the 10% maximum drop, and the margin goes from 41% to 36%, above the 35% minimum the store set. The proposal also notes that if the helmet is sold at €59.90 and goes on promotion in the following 30 days, that promotion's reference price becomes €59.90.
Rui, on the store's team, declined at 9:40am. He knows something the numbers don't show: competitor B is clearing stock before the new model arrives. The decision is logged with a name, a time and the reason, and the agent only proposes the same thing again if the data changes.
"The agent does the maths. The decision stays with whoever knows the store." ShopGuru
A comparison tool shows the prices and waits for someone to read them. The agent prepares the work without anyone asking, as we explain in platform AI or a custom agent.
When competitor analysis doesn't pay off
A store that mainly sells exclusive products, its own or from brands nobody else stocks in Portugal, gains little from tracking prices: customers have nothing to compare with. The same goes for stores that sell on advice. There, time is better spent on product pages that answer customers' questions.
Frequently asked questions
How often should a store run a competitor price analysis?
Once a week is enough for many catalogues. Products sold by many stores under the same reference need more attention, and a minimum gap agreed by the team avoids looking at gaps that don't matter.
Can the agent change the store's prices on its own?
No. A suggested price is only applied with the approval of someone on your team, logged with a name and a time. Your team can approve it, change the amount or decline it.
Does the store have to match the lowest price on the market?
No. The minimum margin and the maximum drop exist so the store doesn't enter a race it doesn't want. Declining a proposal is a normal decision.
Where to start
The first step is to pick a few competitors and the products customers compare most, and to write down the pricing rules before opening the first tab. It's a good topic for a first 30-minute call with a ShopGuru engineer. Book a call.
About this article
Written by ShopGuru's engineers. Published on 16 October 2026. The store, the competitors, the product, the figures and the name in the example are fictional. The rules cited come from Decree-Law No. 70/2007, as amended by Decree-Law No. 109-G/2021, Article 5 of Decree-Law No. 166/2013 as currently in force, Directive (EU) 2019/2161 and the Portuguese Competition Authority's July 2019 report. This article is for information only and is not legal advice.