Understanding Metafield Structure

FitmentPro uses Shopify metafields to store vehicle compatibility data on each product. Understanding this structure can help with advanced use cases and troubleshooting.

Metafield Namespace

All FitmentPro metafields use the namespace vehicle_fitment.

Core Metafields

Key	Type	Purpose
`vehicle_fitment.rules`	JSON	Full fitment data — used by theme blocks for rendering
`vehicle_fitment.search`	list.single_line_text_field	Indexed search terms (e.g., "bmw 3-series 2020")
`vehicle_fitment.brand`	list.single_line_text_field	All brands for collection filters
`vehicle_fitment.model`	list.single_line_text_field	All models for collection filters
`vehicle_fitment.variant`	list.single_line_text_field	All variants for collection filters
`vehicle_fitment.platform`	list.single_line_text_field	All platforms for collection filters
`vehicle_fitment.year_min`	number_integer	Earliest compatible year
`vehicle_fitment.year_max`	number_integer	Latest compatible year

Rules Chunking

Shopify metafields have a 60KB size limit. For products with many vehicles (approximately 350+ rules), FitmentPro automatically splits the data across multiple metafield keys:

vehicle_fitment.rules — First chunk (up to ~350 rules)
vehicle_fitment.rules_2 — Second chunk
vehicle_fitment.rules_3 — Third chunk
And so on...

The theme blocks automatically read all chunks and combine them. You don't need to manage this manually.

Search Index

The vehicle_fitment.search metafield contains indexed terms that make products findable via Shopify's native search. For each rule, it generates entries like:

Brand alone: "bmw"
Brand + Model: "bmw 3-series"
Brand + Model + Year: "bmw 3-series 2020"
Brand + Model + Platform: "bmw 3-series f30"
HSN/TSN codes: "0588|CAU"

Collection Filters

The separate brand, model, variant, platform, year_min, and year_max metafields enable Shopify's native collection filtering. Customers can filter collections by vehicle attributes using Shopify's built-in Search & Discovery app.