HeyDealer API: Certified Used Car Listings and History Data

Two sides of HeyDealer

HeyDealer has two faces, and KoreaCarsAPI treats them as two sources. The marketplace side, heydealer.com, lists certified used cars for sale with an asking price. The dealer side, where member dealers see cars that owners put up for sale, is a separate source called HeyDealer Auction and comes back with is_auction=true.

This article is about the marketplace side. KoreaCarsAPI is an independent data service and is not affiliated with HeyDealer.

HeyDealer also says it offers price lookups and accident or flood history lookups by plate number. Those are services on its own site for its own users. What KoreaCarsAPI returns is the listing data and any public history report attached to it.

Who uses HeyDealer listing data

Certified cars attract buyers who care about condition first, and the people asking for this data reflect that.

• Exporters with clients who ask specifically for checked, certified stock.
• Resellers comparing certified asking prices with ordinary listings for the same model.
• Analysts studying how much a certified status shows up in asking prices.
• Developers building a filter for history-checked cars across several Korean sources.

What a HeyDealer record contains

The vehicle part has year, brand, model, generation, trim, engine volume, fuel, transmission, body type, colour and options. The listing part has the HeyDealer URL, title, odometer, price with currency, photos and the created_at, updated_at and last_seen_at dates, with a dated price history.

Where a public history report exists, vehicle_history_reports[] holds a summary and a timeline. The summary covers first_registered_at, owner_change_count, registration_change_count, insurance claims, own damage and third party damage claims with their costs, total_loss_count, flood_total_loss_count, flood_partial_loss_count and theft_count. The timeline lists dated events, including repairs with parts, labour and painting amounts and the mileage at the time.

For a certified car, this history is the other half of the story. The listing tells you how the car is presented today; the report, when public, tells you what it has been through, in dated steps. Put the two side by side in your tool rather than hiding the report behind a link, because buyers who choose certified stock usually want to read both.

Finding cars with a history report

HeyDealer's own plate number lookups are tools on its site. In the API, the way to focus on cars with history data is the has_history_reports=1 filter on GET /search. Combine it with brand, model and odometer filters, and add domains[] with HeyDealer's ID from GET /domains if you want that source only.

# Cars of one model that carry a public history report
curl --get https://api.auctionsapi.com/search \
  -d "brands[0][id]=BRAND_ID" \
  -d "brands[0][models][0][id]=MODEL_ID" \
  -d has_history_reports=1 \
  -d api_key=$API_KEY

# BRAND_ID and MODEL_ID come from GET /brands and GET /models/{brand_id}

Reading history data responsibly

History reports are valuable, but they need careful reading.

• Only public reports are returned. A missing report never means a clean history.
• Look at the flood fields separately: flood_total_loss_count and flood_partial_loss_count answer different questions.
• Compare repair amounts with the event dates and mileage, not just the total.
• owner_change_count and registration_change_count describe the car's paper trail, which matters to many importers.
• Fields that are not filled for a listing should be shown as unknown, not as zero.

HeyDealer with HeyDealer Auction and the other sources

The most natural pairing is HeyDealer with HeyDealer Auction. One shows certified cars offered to retail buyers, the other shows the cars owners put in front of member dealers. Reading both gives a picture of the same company's flow from the dealer side to the retail side.

For broader price context, add Encar and KB ChaChaCha. And when a VIN is present, GET /cars/vin/{vin} tells you whether the same car is listed somewhere else, possibly with a different history report attached.

Questions