Auto Trader Connect Explained: Stock Sync, Valuations and What It Costs to Integrate

Auto Trader Connect is Auto Trader’s API. It lets a dealer’s website, DMS or stock tool push vehicles, images and prices to Auto Trader in real time, pull valuations (retail, trade and part-exchange), look up the correct derivative from a VRM, and plug into Deal Builder for online reservations and finance. Stock Sync is the reverse direction: your Auto Trader stock feeding your website. Integration cost depends on whether your platform is already a certified partner or you need a bespoke build.

This is the explainer we wish existed when dealers ask us “can our website just talk to Auto Trader?”. It is written for independent and franchised dealers and the people who build their sites, and it backs our Auto Trader integration service.

Why it matters

Auto Trader is where UK car buyers are. Around 80% of UK automotive retailers advertise there and the platform serves about 14,000 retailer forecourts, according to the Auto Trader 2026 annual report. Its own research found that eight in ten buyers only visit Auto Trader and take an average of 87 days to buy. The average retailer paid £2,995 a month in the year to March 2025 (FY25 results).

For that money you want the listing to be right, everywhere, without anyone re-keying it. That is what Connect is for. Auto Trader handled around 155 million technology and data service calls a month in FY26, which tells you how much of the trade already runs on it.

Dealer Portal versus Connect versus Stock Sync

The Dealer Portal is the web interface: manual stock management, pricing insight (Retail Check and Retail Rating), lead management. Every advertiser has it.

Auto Trader Connect is the API behind the portal, opened to certified partners and, for larger or bespoke cases, to the dealer’s own developers. It is real-time and two-way for the things listed below.

Stock Sync is a specific inbound service: Auto Trader pushes your advertised stock to your website or DMS so you maintain vehicles once, in the portal, and the website follows. It suits dealers who manage stock in Auto Trader first and want the website to mirror it. Details are in Auto Trader’s Stock Sync introduction.

What Connect can do

The taxonomy lookup deserves a mention on its own. Most stock errors we see (wrong trim, wrong engine, wrong body) come from someone picking a derivative from a drop-down. Resolving it from the VRM against Auto Trader’s own taxonomy means the advert, the valuation and the website all describe the same car.

Who can integrate

Auto Trader publishes the API at developers.autotrader.co.uk and requires integrations to meet its “integration fundamentals”: OAuth authentication, correct error handling, sensible polling and rate behaviour. Partners are certified before they go live. In practice that means three routes.

A certified platform. Many independent-dealer DMS and website providers (MotorDesk and DealerDesk publish theirs; ask Click Dealer, Dragon2000 and the rest what they support) already have Connect integrations. If you are on one, the integration is a setting and a support ticket, not a project.

A certified integrator building for you. If you have a bespoke website, a group-level DMS or a workflow the platforms do not cover (say, an appraisal app that needs valuations, or a stock tool feeding four portals), an integrator builds against Connect and takes it through certification. This is where we work.

Your own developers. Possible for larger groups with an in-house team, on the same certification terms.

What it costs to integrate

Auto Trader does not publish a price list for Connect access; what you can use is tied to your advertising package and agreed with your account manager, so check current terms with them. The integration work is separate and depends on four things.

Scope: stock push only is a small job; stock plus images plus valuations plus taxonomy plus Deal Builder is a system. Your side: a website with a clean vehicle data model is quick to wire up; a site with stock hard-coded into pages is not. Other feeds: if the same vehicle also goes to Motors.co.uk, eBay, your Google vehicle feed and a Meta catalogue, build one stock model and generate every feed from it rather than five point integrations. Certification: budget time for testing against Auto Trader’s fundamentals and for the review.

We scope this on a fixed price after a short discovery. The cheapest decision a dealer can make is to pick, at the start, whether Auto Trader or the DMS is the master record for stock. Two masters means two truths and daily corrections.

Common mistakes

Treating the portal as the master while a DMS also pushes stock, so the two overwrite each other. Uploading images out of order or below Auto Trader’s minimum resolution. Sending price without the VAT status on commercial vehicles. Ignoring the taxonomy lookup and letting staff free-type derivatives. Polling Connect every few seconds instead of using sensible intervals. Building a “sell my car” widget without caching valuations, then being surprised by the call volume.

FAQ

What is the difference between Auto Trader Connect and Stock Sync?

Connect is the full API: your systems push stock, images and prices to Auto Trader and pull valuations, taxonomy and Deal Builder data. Stock Sync is one inbound service that pushes your Auto Trader stock to your website or DMS.

Can any dealer get API access?

Access is arranged through Auto Trader and depends on your package and on the integration being certified. Most dealers use it through a certified platform; bespoke integrations go through certification with an integrator.

Does Connect give me valuations?

Yes. Retail, trade and part-exchange valuations, including no-VAT variants, are part of the API and are what most “value my part-ex” widgets on dealer websites use.

How much does an Auto Trader integration cost?

Auto Trader does not publish an API price; access terms sit in your package, so check with your account manager. Build cost depends on scope, the state of your website’s stock data, other feeds and certification. We quote fixed prices after discovery.

Want your website, DMS and Auto Trader telling the same story? Start with our Auto Trader integration page, and see stock sync for the multi-portal picture.