Enhance the index


With a basic index and a client that can submit queries and display results, you can achieve an effective search solution. However, Azure Cognitive Search supports several ways to enhance an index to provide a better user experience. This topic describes some of the ways in which you can extend your search solution.


By adding a suggester to an index, you can enable two forms of search-as-you-type experience to help users find relevant results more easily:

  • Suggestions - retrieve and display a list of suggested results as the user types into the search box, without needing to submit the search query.
  • Autocomplete - complete partially typed search terms based on values in index fields.

To implement one or both of these capabilities, create or update an index, defining a suggester for one or more fields.

After you've added a suggester, you can use the suggestion and autocomplete REST API endpoints or the .NET DocumentsOperationsExtensions.Suggest and DocumentsOperationsExtensions.Autocomplete methods to submit a partial search term and retrieve a list of suggested results or autocompleted terms to display in the user interface.


For more information about suggesters, see Add autocomplete and suggestions to client apps in the Azure Cognitive Search documentation.

Custom scoring and result boosting

By default, search results are sorted by a relevance score that is calculated based on a term-frequency/inverse-document-frequency (TF/IDF) algorithm. You can customize the way this score is calculated by defining a scoring profile that applies a weighting value to specific fields - essentially increasing the search score for documents when the search term is found in those fields. Additionally, you can boost results based on field values - for example, increasing the relevancy score for documents based on how recently they were modified or their file size.

After you've defined a scoring profile, you can specify its use in an individual search, or you can modify an index definition so that it uses your custom scoring profile by default.


For more information about scoring profiles, see Scoring Profiles in the Azure Cognitive Search documentation.


Often, the same thing can be referred to in multiple ways. For example, someone searching for information about the United Kingdom might use any of the following terms:

  • United Kingdom
  • UK
  • Great Britain*
  • GB*

*To be accurate, the UK and Great Britain are different entities - but they're commonly confused with one another; so it's reasonable to assume that someone searching for "United Kingdom" might be interested in results that reference "Great Britain".

To help users find the information they need, you can define synonym maps that link related terms together. You can then apply those synonym maps to individual fields in an index, so that when a user searches for a particular term, documents with fields that contain the term or any of its synonyms will be included in the results.


For more information about synonym maps, see Synonyms in Azure Cognitive Search in the Azure Cognitive Search documentation.