How Otsledit Finds the Price on a Page: AI Detection and the Simple Heuristic

A product page can show a dozen numbers that all look like prices: the current one, the crossed-out old one, a monthly installment, shipping, a club price, and prices of recommended products further down. A price tracker is only as good as its ability to pick the right one. Here is how Otsledit does it, and what to do when it picks wrong.

Otsledit finds the price in two ways. The neural network reads the whole page and picks the main price. The simple heuristic takes the price with the largest font. Both run inside your browser — the page never leaves it, and nothing about what you track is sent anywhere for analysis.

The neural network looks at more than size. For every number that could be a price it weighs a set of signals: the font, whether a currency symbol sits next to it, whether the number also appears in the page’s structured data, whether it is crossed out, where it sits on the page, and whether it belongs to a section that usually holds other people’s prices — recommendations, sponsored blocks, delivery. That is why it can pick the main price on a page where the main price is not the largest one.

The simple heuristic does exactly what its name says: among the prices on the page it takes the one set in the largest font. On a clean product page that is almost always the right answer, and it is the reason the heuristic often wins on stores with a plain layout. It has no opinion about context, so it is predictable — and predictable is useful when the neural network keeps landing on the wrong number.

In both cases the price is found again on every check, not just once when the track is created. This matters: stores redesign their pages, and a track that had to follow one fixed element would quietly break. Automatic detection lets a track survive a layout change on its own.

Each track carries a small badge on its card in the watchlist — AI for the neural network, A for the simple heuristic. Click the badge to switch that one track to the other method. The switch in the settings does not touch tracks you already have: it only decides which method new tracks are created with.

There is a third state, and it is the strongest one: no badge at all. That means you picked the price by hand — from the list of candidates in the popup, or by choosing the element on the page yourself. Such a track follows exactly that element by its CSS selector, and automatic detection leaves it alone. If a store keeps confusing both methods, picking the price by hand is the way to end the argument.

So when should you switch? If a track shows a suspiciously small number, it has probably latched onto an installment or a shipping fee — try the other method. If it shows a suspiciously large one, it may have taken a crossed-out old price or a bundle. If the number keeps jumping between two values on the same page, the store is likely showing different prices to different regions, and the track settings have a switch for ignoring currency changes.

A last practical note: one page can beat one method and lose to the other, and there is no universal winner. Switch the badge, and if that does not help, create the track again and pick the price by hand. Sometimes a working track is only found by trying every option — and once it works, it keeps working.