Guide

Where auto parts stores get vehicle fitment data

Every vehicle search needs a record of which part fits which vehicle. Nobody hands a small store that record complete. Here is where it actually comes from, what each source costs, and what each one leaves you to finish yourself.

Written by the developer of Fitment Sync, a fitment app for Shopify. We do not sell fitment data and have nothing to gain from which source you pick.

Two different things get called "fitment data"

Before comparing sources, separate the two halves:

1. The vehicle list. Every year, make, model, submodel, engine, drive type and body style that exists in your market, spelled consistently.
2. The part-to-vehicle mapping. Which of your part numbers fits which of those vehicles, and in which position.

The second one is the hard one. A vehicle list can be bought or approximated. The mapping only exists where someone engineered or tested the part, which means it starts with the brand that makes it, and reaches you through whoever sells it to you.

The industry standard, and what it costs

The aftermarket has a standard for exactly this. The Auto Care Association publishes ACES, the Aftermarket Catalog Exchange Standard, for fitment data, and PIES, the Product Information Exchange Standard, for product information. Both are XML, and both lean on reference databases: VCdb for vehicle configurations, Qdb for qualifiers, PCdb for product classification, PAdb for product attributes, and the Brand Table.

Those reference databases are subscriptions, and a subscription is required to create or receive ACES and PIES files. At the time of writing the Auto Care Association's published pricing starts at $2,500 a year for its entry-level ACES and PIES package for member companies under $1 million in global revenue, with the standalone ACES subscription starting at $3,150 for members and $4,410 for non-members, renewed annually.

That number explains a lot about how small stores work. A shop doing a few hundred thousand a year does not subscribe to VCdb to read a file from one supplier. It works from spreadsheets, and the spreadsheets are messier than the standard, which is why cleaning them is part of the job.

The realistic sources

Your suppliers and distributors

This is where most stores start, and for many it is enough. Ask your rep for the fitment file for the lines you carry. You will usually get a spreadsheet, sometimes a CSV, and occasionally ACES XML.

What to expect: coverage limited to their lines, a different column layout from every supplier, vehicle names spelled their way, and updates whenever they feel like it. The work is not getting the file, it is that each one needs the same cleaning again next month.

The brands directly

Manufacturers keep the authoritative version of their own applications, and many will send it to a retailer who asks, through a dealer portal or an email to the rep. If what arrives is ACES XML, be aware that the codes inside refer to the VCdb subscription described above — a brand can also usually export a readable spreadsheet, so ask for that first.

Marketplaces you already sell on

If you list on eBay Motors with parts compatibility, you already hold a version of this data inside your listings. eBay's compatibility is built on its own Master Vehicle List, managed in bulk through Seller Hub Reports, with a limit of 3,000 compatible vehicles per listing.

Two things to know before treating it as your source of truth. The vehicle names follow eBay's list, so they will not match another system's spelling without mapping. And compatibility that a marketplace added automatically is a suggestion, not something the brand stated — sellers regularly report auto-added fitment that is wrong for engine variants.

Commercial fitment databases

Several companies license normalised fitment across many brands. What you are buying is the normalisation: one spelling of each vehicle, one shape of record, updated on a schedule. Pricing is usually quoted rather than published.

Before signing, get answers to three questions in writing:

• Does the licence cover your storefront? Displaying fitment publicly is a different use from internal lookup, and some licences price them differently.
• What happens when you stop paying? Some licences require you to remove the data. If so, your vehicle search stops working the month you cancel.
• Which of your brands are actually covered, at what depth? Ask for a sample limited to the brands you sell, not a total record count.

Your own work

For a few hundred SKUs, building the mapping by hand from catalog PDFs and manufacturer sites is real and normal. It is slow, and it is also the data nobody else has: the applications you confirmed because a customer fitted the part and told you.

Keep it in a spreadsheet with the same columns as your supplier files — SKU, year, make, model, submodel, engine, position — so it can be imported the same way. Its value is lost if it only exists as notes.

What VIN lookup does not solve

VIN lookup is often suggested as a shortcut. It is not a source of fitment. The NHTSA's public vPIC API decodes a VIN into vehicle attributes such as make, model and year, and that is all it does. You still need a record of which part fits that vehicle. VIN decoding removes the step where the shopper picks their vehicle; it does not tell you anything about your parts.

How to judge a source before you commit

• Coverage of your brands, not of the market. A database with two million records is worth nothing if it is thin on the four lines you actually sell.
• Granularity. Year, make and model alone will sell the wrong part on vehicles where the engine, drive type or body style matters. Check the file has those columns filled, not just present.
• Position. Front and rear, left and right, upper and lower. Without it, a shopper buys the rear rotor for a front axle.
• Update cadence, and what an update looks like. A full catalog every month and a file of changes are different problems to load.
• Whether you can leave with your data. If it cannot be exported as a plain file, you are renting your own catalog.

Once you have a file

Getting the data is the first half. Loading it every month without destroying what you already built is the other half, and it is where stores lose the work they have done. A supplier file usually covers one brand, so importing it should change that brand and nothing else.

That is covered in the next guide: importing a supplier fitment file without losing what you already have. You can also try the four import scopes on sample supplier files in the interactive demo.

Sources: the Auto Care Association's published data standards and subscription pricing, eBay's seller documentation for parts compatibility, and the NHTSA vPIC API documentation. Prices were correct in September 2026.