Dev log

The same Cyprus car, three listings: how AllCars spots duplicates

Sellers list the same used car in Cyprus on more than one site, sometimes at different prices. AllCars unifies them so you see one car, one timeline, one fair price. Here's the careful version of how it works.

If you've ever browsed for a used car in Cyprus, you've seen this: the same Mercedes, listed three times, by what looks like three different people, at three slightly different prices. It's the same car. AllCars is supposed to figure that out so your search isn't full of phantom duplicates.

The risk on the other side is worse: merging two different cars by accident. The price chart goes haywire, the deal score lies, the listing gets a wrong identity. The matcher errs strongly on the side of "different car until proven otherwise".

Four signals, none of them solo

It uses four families of evidence to decide if two listings are the same physical car:

Image fingerprints. When the same photos show up on two listings, that's a strong signal. AllCars doesn't store the images themselves — only a small fingerprint that's good for "did these come from the same source" without keeping any personal-looking data.

Specs match. Year, make, model, mileage, engine. Close enough on all of them, plus a small enough price gap, and the listings might be the same car.

Identity hints. Sometimes the same contact appears across listings; sometimes a number plate is visible in a public photo. These count when present, but never on their own.

Description signals. Service-history phrasing, identical typos, a specific accident reference — sellers leave fingerprints in their wording.

The rule: 2+, or 1 strong + identity

No single signal merges anything. The rule is two-plus signals agreeing, or one strong signal plus a confirming identity hint. I've watched single-signal merges nearly merge different cars more than once, so they're off the table now.

Combine that with the hard-veto rules — body type, fuel, year, colour mismatches stop a merge cold — and the matcher becomes a careful, conservative thing. It misses a few legitimate merges where data is sparse on both sides, and it accepts that trade. A missed merge is just two listings instead of one. A wrong merge corrupts the timeline of a car you might actually buy.

Why this matters when you're using AllCars: the listing card shows one Mercedes, with the lowest live price among its duplicates and a price chart spanning all of them. You don't have to mentally de-duplicate. I did it for you, carefully.