I wouldn't call that an antipattern. I treat other systems like I do the database and enforce consistency at the API level. I wouldn't ask for a database to b

I wouldn't call that an antipattern. I treat other systems like I do the database and enforce consistency at the API level. I wouldn't ask for a database to be totally untyped (and thus silently coerce things into its internal types in reality), so I don't ask for the same in an API. Though, I can understand some people have differing preferences---MongoDB is popular for example---but I wouldn't call it an anti-pattern no matter which choice one makes.