There are many HTTP codes which you can use as a result for your API. With most API's you can be happy if you're getting a 400 when you're running into an error and not just an exeption in the body and a 200 as HTTP code.

I stubled apon a nice one for deletion endpoints. Meaning you want to say everthing worked but you won't return any more information by design. For that type you can use 204 No Content.

See more success codes on the wikipedia page.