Built-in ranking rules

Built-in ranking rules are the core of Meilisearch’s relevancy calculations.

There are two types of ranking rules in Meilisearch: built-in ranking rules and custom ranking rules. This article describes the main aspects of using and configuring built-in ranking rules.

Built-in ranking rules are the core of Meilisearch’s relevancy calculations.

List of built-in ranking rules

Meilisearch contains six built-in ranking rules in the following order:

[
  "words",
  "typo",
  "proximity",
  "attribute",
  "sort",
  "exactness"
]

Depending on your needs, you might want to change this order. To do so, use the update settings endpoint or update ranking rules endpoint.

1. Words

Results are sorted by decreasing number of matched query terms. Returns documents that contain all query terms first.

The words rule works from right to left. Therefore, the order of the query string impacts the order of results.

For example, if someone were to search batman dark knight, the words rule would rank documents containing all three terms first, documents containing only batman and dark second, and documents containing only batman third.

2. Typo

Results are sorted by increasing number of typos. Returns documents that match query terms with fewer typos first.

3. Proximity

Results are sorted by increasing distance between matched query terms. Returns documents where query terms occur close together and in the same order as the query string first.

It is possible to lower the precision of this ranking rule. This may significantly improve indexing performance. In a minority of use cases, lowering precision may also lead to lower search relevancy for queries using multiple search terms.

4. Attribute

Results are sorted according to the attribute ranking order. Returns documents that contain query terms in more important attributes first.

Also, note the documents with attributes containing the query words at the beginning of the attribute will be considered more relevant than documents containing the query words at the end of the attributes.

5. Sort

Results are sorted according to parameters decided at query time. When the sort ranking rule is in a higher position, sorting is exhaustive: results will be less relevant but follow the user-defined sorting order more closely. When sort is in a lower position, sorting is relevant: results will be very relevant but might not always follow the order defined by the user.

Differently from other ranking rules, sort is only active for queries containing the sort search parameter. If a search request does not contain sort, or if its value is invalid, this rule will be ignored.

6. Exactness

Results are sorted by the similarity of the matched words with the query words. Returns documents that contain exactly the same terms as the ones queried first.

Examples

Typo

Typo

• vogli: 0 typo
• volli: 1 typo

The typo rule sorts the results by increasing number of typos on matched query words.