Six years on a dealer platform, and the parts I put my name on

What it is

Tadvantage is the WordPress multisite platform behind Convertus dealer websites — Project Achilles on the inside, which is the name anyone who worked on it will recognise. It carries ten OEM and dealer-group themes and thirty-five-plus custom plugins covering inventory, showroom, pricing, SEO, integrations and analytics, with Vue on the interactive surfaces and PHP underneath. Convertus is part of Trader Corporation, the company behind AutoTrader.ca.

Where I sat in it

I was the top all-time contributor: 1,682 commits and 358 merged pull requests on a codebase with more than a hundred engineers in its history. 253 tickets, 177 release commits, 39 hotfixes. That count starts in January 2019 rather than at my start date, because my first couple of months went in under a colleague’s pull requests. I owned production releases from v3 through v12.7 and merged the French translations for most of them.

Those figures come from the repository’s own history. It is private, so unlike everything else on this site you cannot click through and check it — I can walk you through it on a call.

Pricing, which is where the risk is

A price appears in more places than anyone expects: four search-result card versions, the vehicle detail page, the quick view, the inventory carousel, and a calculator with cash, finance and lease tabs. If any one of them disagrees with another, the customer stops trusting the number and the dealer carries the compliance risk. I built Canada’s federal luxury tax through all of them, behind a feature flag so it could go out dealer by dealer.

Performance

I created the object-caching repository and put the platform on Object Cache Pro against shared Redis clusters — key prefixes, global groups, prefetching, connection timeouts — load-tested on a dedicated environment before it went near production. Later I rolled page caching out to the whole fleet with WP-CLI, excluding the inventory and showroom routes that can never be served stale, wired into the deploy scripts so every new site got it automatically.

Integrations

CARFAX v3 with Auth0 token generation. Ford Model E inventory and OEM window stickers. Motocommerce build-and-price with deep links carrying colour and trim. Honda, Lincoln and Jeep showroom mapping. Hyundai Roadster. Dealer data feeds to Shift Digital and CarGurus over SFTP.

The unglamorous half

I built the SEO foundation — inventory sitemaps in English and French, Product and Breadcrumb schema with VIN as the identifier, canonical handling across the detail page, the search page and the print view — and maintained a fork of Yoast carrying inventory sitemap support through three major versions. I also built the Bill S-211 compliance pages that publish themselves to every dealer site in both languages, because a legal requirement nobody configures by hand is a legal requirement that actually gets met.

What I would do differently

Inventory changes were polled; webhooks would have been more accurate and less wasteful. Some jQuery stayed for legacy integration rather than being migrated — it shipped faster and left debt, and both are true.

Above all I would instrument it from day one. Save, remove and compare events were never measured, which is why this case study carries no adoption figures: the data to make that argument was not collected. That is the real cost of shipping a feature before deciding how you will know whether it worked.