WordPress REST API parameters are not affecting a response

If results should be ordered by a method other than the default asc or desc, you should also pass the orderby parameter. This gives you the ability to order by title, date, parent, type and many more that can be seen here.

For example, a request ordering the results a-z by title would be:

http://api-address.com/wp-json/wp/v2/posts/?categories=12&order=asc&orderby=title