How to Add Vehicle Fitment to Your Shopify Store

If you sell auto parts online, one question drives your conversion rate and your returns rate more than anything else: "will this fit my car?" Get it answered early and confidently, and customers buy. Leave it ambiguous, and they either do not buy or -- worse -- buy the wrong part and return it.

Why fitment is the whole game for parts stores

• Wrong-part returns are expensive. Every mis-fitting part is double shipping, restocking labour, and an unhappy customer.
• Fitment doubt kills conversion. A customer who is not sure will open a new tab to research -- and often never come back.
• Vehicle-aware stores can filter. Once you know the customer drives a 2012 Hilux, you can show only products that fit it, which turns your whole catalogue into a personalised one.

Two ways to identify the customer's vehicle

Option 1: make/model/year dropdowns. The classic approach. It works, but it asks the customer to do the work, and "what year is your car?" is genuinely ambiguous for many owners -- compliance date, build date, and model year often differ.

Option 2: rego lookup. The customer types their number plate and picks their state -- two things every driver knows -- and the vehicle is identified for them: year range, make, model, and engine. It is faster, feels a little bit magic, and removes the guesswork that causes fitment errors in the first place.

The best setups offer both: plate lookup as the primary path, dropdowns as the fallback for unregistered vehicles or customers who prefer it.

How the PlateAPI Shopify widget works

PlateAPI ships a Shopify theme app extension that adds an "Add My Vehicle" button to your storefront. The flow for your customer:

1. They click the trigger button and a slide-out panel opens.
2. They enter their plate and tap their state on a selector covering all eight states and territories.
3. The widget calls the PlateAPI lookup and shows the identified vehicle with an "Is this your car?" confirmation. If the plate maps to more than one variant, they pick theirs from a list.
4. On confirmation, the vehicle is saved in the browser and the widget fires a JavaScript event your theme can listen for -- so you can filter collections, badge compatible products, or pre-fill fitment fields.

Everything customer-facing is configurable in the Shopify theme editor: colours, button text, panel position and width, so it matches your brand without touching code.

Setting it up

1. Get a PlateAPI account on any paid plan -- Shopify integration is included on all of them, and lookups from your store count against your normal monthly allowance.
2. Install the widget -- contact support with your store domain and we set the theme app extension up with you.
3. Add the block in your theme editor -- the "rego lookup" block appears in your theme's app blocks; place it in the header, a landing section, or wherever suits.
4. Style it in the theme editor settings, then test with your own plate.

Using the vehicle data in your theme

Once a customer confirms their vehicle, your theme receives a custom event with the full vehicle object -- the same year range, make, model, and engine data documented in the API reference. Typical uses:

• Redirect to a collection filtered by the vehicle (if your products are tagged by fitment)
• Show a "fits your 2012-2015 TOYOTA HILUX" badge on compatible product pages
• Store the vehicle against the cart as attributes so your team sees it on the order

For the dropdown fallback, paid plans also include the vehicle database endpoint -- cascading make, model, and year lists covering 32,000+ Australian-market vehicles, which the widget's manual mode uses out of the box.

Try it first

The live demo on our homepage is the same lookup the widget performs -- test it with your own rego and see exactly what your customers would see.