Can we assign a specific user to a variant of the A/B Test?

You are not able to allocate a specific userToken to a specific variant - this is done at random by the A/B Test.

Users are identified by setting a userToken. If you’re using InstantSearch or one of our API clients, the userToken can be sent to Algolia with the userToken parameter, or with the X-Algolia-UserToken request header.

You can review our documentation here to understand how our A/B test allocates users to different variants (A or B).