Atlas Search makes text fields searchable by creating Atlas Search indexes in MongoDB Atlas. You can control the index characteristics, such as where to break up word groupings and whether to consider punctuation, by specifying an analyzer to use when creating the index.

In order to create an Atlas Search index on a field, MongoDB looks at the specified field and breaks it down into a list of searchable words. This process is called analysis, and you can control the analysis parameters by specifying an analyzer. Atlas Search has many built-in analyzers which you can specify at the time of index creation and/or at the time of query execution.

You can specify an analyzer to use during index creation in the index definition. If you don’t specify an analyzer, MongoDB uses the default standard analyzer.

Built-in analyzers are available to create indexes tailored to several languages and search configurations. If none of the built-in analyzers suits your requirements, you can override an existing analyzer with a custom set of parameters.

Analyzer Description
Standard The default analyzer for all Atlas Search indexes and queries.
Simple Divides text into searchable terms wherever it finds a non-letter character.
Whitespace Divides text into searchable terms wherever it finds a whitespace character.
Language A set of language-specific text analyzers.
Keyword Indexes text fields as single terms.