Does it support filtering post/product by author?

Hello, thank you for your message. I should say that it depends on the way the Author characteristic was created.
Searchanise plugin indexes global attributes that were created on the page Products > Attributes. The attributes created this way could be used in the search process and filter generating.
If the attribute is individual for some specific products, it will be indexed by our system and taken for the search, yet there will be no way to create a filter with this attribute.
I hope this information helps. If any further questions appear or any additional information is needed, please feel free to contact us via [email protected]. We’re always here to help.