Rules overview

Search needs to be flexible. When you hold a promotion, you shouldn’t need to reconfigure search settings or modify individual records. If one of your products isn’t appearing where you want it to in your search results, you should be able to reposition it quickly.

Rules let you make precise and (if desired) temporary modifications to your search results.

Relevance and index settings provide the general structure for your search results. Rules let you optimize and dynamically adjust that structure.

Rules don’t replace a good index configuration. Make sure you adjust your general relevance before adding rules.

What are rules used for?

Rules let you make precise, predetermined changes to your search results. For example, you can pin or hide items, boost or bury categories, or filter results based on the query. You can also enable rules for a fixed time, making rules a great way of implementing sales or promotions.

You’re limited to 10,000 rules per index.

Rules are typically used either for merchandising or fine-tuning your search and relevance.

To see some typical applications for rules, check out the sections on merchandising with rules and detecting user intent with rules.

Rule structure

Rules consist of three parts: conditions, consequences, and a validity period. Of these three parts, only the consequence is required. If one of a rule’s conditions is met, Algolia applies its consequences. If a rule has no conditions, Algolia always applies its consequences.

Rules target specific indices, but can be copied to replicas or other indices.

Conditions

A rule can have up to 25 conditions. If a rule has multiple conditions, it gets activated as soon as one of its conditions is met. In other words, conditions have an or relationship to one another. Conditions can contain a pattern string, anchoring, a context, or filters, though none are required.

To decide if a rule’s consequences should be applied, Algolia:

• Compares the condition’s pattern string with a user’s query.

• Bases the comparison on the condition’s anchoring. Values for anchoring are: is, contains, starts with, and ends with. The anchoring determines what part of the query the pattern must match: all of it, part of it, the beginning, or the end.

• If you enable alternatives in the condition, user queries can match the condition’s pattern, even if the query is a plural, synonym, or typo of the pattern. If you don’t enable alternatives, user queries must exactly match the condition’s pattern string and anchoring.
• It compares the condition’s filters to the filters applied to the search.
• It compares the condition’s context to the search’s ruleContexts.

If a single condition includes a pattern string, filters, and a context, a search must match all three for the condition to be met. If you create three different conditions for each, only one must be met for Algolia to activate the rule.

If a condition has a pattern string that set to an empty string with is anchoring, Algolia applies the rule if users haven’t yet entered a query.

If a condition has neither pattern, anchoring, context, or filters, it’s a conditionless rule, and Algolia applies it to every search.

Rules can respond to different types of conditions:

• Query patterns
• Filters
• Context-only
• Conditionless.

Example conditions

Using a pattern with is anchoring

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{
  "pattern": "sale",
  "anchoring": "is"
}

Trigger a rule with this condition whenever the query string is the word sale and nothing else. If the query contains other words, the rule isn’t triggered.

Using a pattern with contains anchoring

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{
  "pattern": "featured",
  "anchoring": "contains"
}

Trigger a rule with this condition whenever the query string contains the word featured. The query can include other words.

Using context

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{
  "context": "mobile"
}

Trigger a rule with this condition whenever the search includes mobile in the ruleContexts.

Using filters

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{
  "filters": "category:TV"
}

Trigger a rule with this condition whenever the filter { "filters": "category:TV" } is applied to the query.

The filters condition rejects an OR combination of different attributes. For example, "filters": "brand:Guess OR color:orange" returns an error.

Using pattern, filters, and context

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{
  "pattern": "featured",
  "anchoring": "contains",
  "filters": "category:TV",
  "context": "mobile"
}

Trigger a rule with this condition whenever the query string contains the word featured, the search includes category:TV in its filters, and includes mobile in its ruleContexts.

Using an empty string pattern

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{
  "pattern": "",
  "anchoring": "is"
}

Trigges a rule with this condition whenever there is an empty search. The rule is turned off as soon as a user starts typing.

Consequences

Though conditions aren’t required, rules must have at least one consequence. Consequences modify the results returned by a search. The possible consequences are:

• Pin an Item: Inserts an item at a specific position. If the item is already in the list of results, this item is moved to that position.
• Hide an Item: Removes a specific result from the list of results.
• Add a Query Parameter: Adds a query parameter to your user’s search. For example, you could decrease the aroundRadius if your user’s query includes the words “near me”.
• Remove Word: Removes a specific word from your user’s search query (for search, not display purposes).
• Replace Word: Replaces a word from your user’s search query with another word (for search, not display purposes).
• Replace Query: Replaces the entire user search query with another query (for search, not display purposes).
• Return Custom Data: Adds custom JSON data to the search response.
• Filter/Boost Matching Attributes: Applies filters or optionalFilters matching the query to the results.

Validity period

If you want to apply a rule temporarily, you can set a validity period. The validity period determines how long a rule remains active. You can use this to automatically end promotions or sales on a specific date.

Rules responding to user queries

Rules can parse your users’ queries and apply a consequence if the query matches the rule’s condition. Queries are matched with conditions in the following ways:

• is: the entire query matches the condition string.
• contains: the entire query contains the condition string
• starts with: the query starts with the condition string.
• ends with: the query ends with the condition string.

If you would like to trigger a rule on an empty query use a context-only-rule, use is anchoring, but set the text to be an empty string, or leave it blank in the dashboard.

Rules responding to applied filters

If a rule’s condition includes filters, Algolia applies that rule’s consequences only if the filters in a search’s query parameters exactly match the condition’s filters.

For example, Algolia only triggers a rule with the condition {"filters": "category:TV"}, if category is filtered on the valueTV, and on this value only. Other filters like "category:Smartphone" or "category:TV OR category:Smartphone" don’t trigger the rule.

The primary goal of this condition is to create rules that are triggered on specific category pages or when a user applies specific filters. For example, you can define a rule with the condition {"filters": "category:TV"} and a consequence to promote specific items. The rule would be triggered when a user lands on the TV category page.

For more information, see Filters can trigger rules.

To use an attribute in a Rule condition with filters, you must first declare it in attributesForFaceting.

Context-only rules

If a rule’s condition includes only a context, then that rule’s consequence applies only if the rule’s context exactly matches a value in the ruleContexts parameter of a user’s search.

What are contexts?

Contexts provide information about your user’s search environment: for example, what section of a website they’re currently visiting or what device they’re using. A context can be any string value that doesn’t include whitespace characters. The search condition it specifies must be identifiable at search time. You must implement the logic to conditionally send contexts with your users’ queries. You can pass contexts through the ruleContexts search parameter.

Implementation

To implement a rule with a context condition, you must:

1. Create the rule with the dashboard or the API.
2. Conditionally assign its associated context to your user’s searches.

To clarify the process, consider this example. Suppose you own an electronics store. Using analytics tags, you’ve discovered that mobile users rarely find what they’re looking for on the first page of search results. With some testing, you realize that this is because vague searches for accessories like “chargers” or “cases” return laptop chargers and cases first.

You want to add a rule that promotes all items in your catalog with the “phone” tag, but only if a user is searching from a mobile platform. Hence, if mobile users search for cases, you can assume that they prefer phone cases over laptop cases. If they search for chargers, phone chargers should show up first.

Conditionless rules

Rules without conditions apply to every search on the index. They’re an effective way of temporarily modifying your site’s search for a predefined time, for example, for seasonal promotions.

Context-only and conditionless rules deactivate consequences

Since conditionless and context-only rules don’t include a query as a condition, these consequences are deactivated.

These limitations only apply to context-only and conditionless rules. Other rules can use the full range of consequences.