Why do bots scrape your prices and undercut you by a cent?

November 12, 2026 - BazaarFort

Short answer: Bots scrape your prices every few minutes and reprice the competing listing one cent below yours, so the marketplace algorithm keeps handing them the sale. The scrape is cheap and constant, the undercut is too small for a shopper to notice, and the damage is the slow bleed of the orders you never see.

The one-cent gap is a strategy, not a coincidence

A shopper sees two listings at nearly the same price and picks the cheaper one, or picks the one the algorithm puts first. A one-cent difference is invisible to the shopper and decisive to the algorithm. The listing that is one cent cheaper wins the buy box, the top of the search results, and the order. The listing that is one cent dearer waits.

Nobody reprices by hand every four minutes. The operator runs a scraper that reads your price, your stock, and your shipping time, then sets their price one cent below yours and walks away. When you change your price, theirs changes within minutes. When you run a sale, theirs follows. The gap stays one cent, and the orders keep flowing to the cheaper listing.

DataDome's 2026 State of Bot and Agent Security report puts a number on the habit. Scraping made up 70.9 percent of all bad bot traffic in the year to June 2026, up 185.2 percent year over year. Price scraping is the largest single use of that traffic, because a price is the most valuable fact a competitor can steal, and it is also the easiest to collect at scale.

What the scraper actually collects

The price is the headline, but the scraper takes the whole listing: your title, your description, your images, your review count, your stock status, and your shipping promise. The copy of your listing is then used to build a competing listing that looks like yours, priced a cent lower, with your own words doing the selling.

The scrape runs from residential proxies, which is why blocking the obvious IP addresses does nothing. CHEQ's research on residential proxies explains the mechanism: the traffic comes through real household connections, so each request looks like a shopper on a home network, and a rate limit keyed to one IP address sees a thousand different shoppers instead of one bot.

The cadence matters. A scraper that checks your price every few minutes catches every change you make, including the ones you make at 2 a.m. to test a new price point. Your test becomes their data before you have read the results.

Why the marketplace does not stop it

The marketplace has the same problem you do. The scraper looks like traffic, and traffic is what the marketplace sells. A marketplace that blocks every scraper also blocks the price comparison tools, the research crawlers, and the shoppers on shared connections. The line between a legitimate crawler and a price scraper is the behavior, and the behavior is designed to sit on the right side of it.

The platform also profits from the competition the scraper creates. Two listings fighting over one cent keep prices low, and low prices keep shoppers coming back. The seller who loses the sale to a one-cent undercut is paying for a price war they never agreed to join.

How to tell you are being scraped, and what to do

Check the pattern, not the price. A competitor whose price follows yours within minutes, across every listing, at every hour, is not watching you. They are running a bot. A competitor whose price moves once a week is a person.

Change something the scraper cannot follow cheaply. Bundle the product with a second item, change the listing title, or move the price to a point where the one-cent gap costs the competitor more than it gains. A scraper that has to re-read your whole catalog after every change costs the operator money, and the operator's margin on a one-cent gap is thin.

And report the pattern with timestamps. A single screenshot proves nothing. A log showing your price change at 09:14 and their price change at 09:17, repeated across a week, is the evidence the platform's trust team needs to act on the account instead of the listing.

Keep reading: How do bots fake the sales that win a marketplace bestseller badge?, How do bots use marketplace messages to phish sellers out of their accounts?, and Review velocity: how a flood of five-star reviews gets your listing flagged cover the nearby cases in this series.

Frequently asked questions

Why do bots scrape prices instead of just copying the listing once?

Because prices change, and a static copy goes stale in a day. A scraper that checks every few minutes catches every price change, sale, and stock update, so the competing listing stays one cent below yours around the clock.

Is price scraping illegal?

Scraping publicly visible prices is usually not a crime, but using the scraped data to mislead shoppers, copying listing text and images, or breaching a site's terms can be. The practical defence is technical and commercial, not legal: make the scrape expensive and the undercut unprofitable.

How can I tell if a competitor is using a bot to reprice?

Watch the timing. A competitor whose price follows yours within minutes, across every listing, at every hour of the day, is running automation. A person reprices in batches, during working hours, and misses changes.

What does residential proxy traffic have to do with price scraping?

Scrapers route requests through residential proxies, real household internet connections, so each request looks like an ordinary shopper. That is why IP blocking and simple rate limits miss them: the bot is a thousand different IPs, not one.