Guide 11 · Developer docs

Search, filtering and faceted navigation

Site search on Core dna is an Elasticsearch index that the platform fills and queries, and a page you build. What reaches the index, search views, the search page, product facets, filtered listings that need no index, and when to go beyond the built-in index.

Unit 03 of 05 4 pages

Faceted navigation for product finders

Updated 23/10/2026 01:45

Product facets end to end: defining them and filling them through the mapping template, a filter interface whose state lives in the URL, combining facets with a text query, and keeping counts fast on a large catalogue. For developers building a product finder.

Facets on Core dna are for products: they live in a separate facets index, filled by a mapping template you write. Start with Facets and the mapping template, which also says which filters belong to site search or to a plain listing instead, and points back to the content-types guide for the modelling decision behind each facet.

A filter interface that keeps its state in the URL renders the facets as a form that works without a script, then enhances it; keeping the state in the address bar is a requirement, not a style. Facets with a text query explains what every count on the page means once something is selected, and what to show when nothing is left. Facet counts at scale is for when the finder gets slow: what each count costs, and the two ways to pay less.

In this unit

Read in order

01 Facets and the mapping template Which kind of filter belongs where, how a facet is defined under Search › Facets, the mapping template that decides what each product puts into the facets index, price ranges as bands, and a Faceted Search view that returns the facets with their counts. 02 A filter interface that keeps its state in the URL Why facet selections belong in the URL, a filter form in both engines that works with no script at all, and a script that updates the results without a reload while keeping the address bar, the back button and keyboard focus right. 03 Facets with a text query What a text query matches on a product finder and what it does to the order of results, how facet counts follow a selection and how to get true counts within a facet, and what to show when a selection excludes every result. 04 Facet counts at scale Facet counts are the part of a product finder that gets slow. What each count costs, the two ways to keep it fast, counting only the facets a page shows and caching the counts, with the trade-off each carries, and why counts go stale whatever you do.

Objects ReferenceGenerated from the platform, so it is always current

API ReferenceEvery REST endpoint, in cURL, PHP, Python and JavaScript

Faceted navigation for product finders

In this unit