Query Suggestions are powered by a Query Suggestions index, and requests to this index are billed just like any other search request. However, whether they increase your total number of billable operations depends on how your frontend is implemented.
Query Suggestions = Standard Search Requests
When your application sends a request to the Query Suggestions index, that request is counted as a billable search operation, the same as any request to a regular index. You can learn more in the article:
How does Algolia count records and operations
Optimized Example: One request, multiple results
In many implementations (such as using the Autocomplete library), you can retrieve both Query Suggestions and search hits in a single request using Algolia's multipleQueries functionality under the hood.
For example, in this CodeSandbox demo, the network tab shows only one request per keystroke, but results from both the hits index and the suggestions index are returned together. This means only one billable operation occurs per keystroke - even though you're querying two indices.
Less optimized example: Separate requests
In other implementations, such as in our guide on integrating Autocomplete with React InstantSearch Hooks, the Autocomplete menu handles suggestions, while InstantSearch handles hits in separate components. In this case, each component sends its own request, which leads to two billable operations per keystroke.
Summary
Query Suggestions are billable search requests.
You can combine them with hits in a single request to avoid increasing your operation count.
Frontend implementation choices determine whether your request volume increases.