You're spot on. This pertains to a more or less homegrown query DSL (or family of DSLs) that gets "translated," in a sense, by the server to SQL and/or MongoDB

You're spot on. This pertains to a more or less homegrown query DSL (or family of DSLs) that gets "translated," in a sense, by the server to SQL and/or MongoDB queries. The read-only endpoints being queried represent collections of a great many items, so being able to filter–search for, say, a dozen to a few thousand at a time is a real need. Using GraphQL would probably be better, but if it's not an option then it's not an option. I am, though, looking at dynamic-rest[1] and Eve's "projections"[2] for inspiration, i.e. to allow for flexible queries that more closely match particular use cases (of the API's users). [1] https://github.com/AltSchool/dynamic-rest https://github.com/AltSchool/dynamic-rest [2] http://python-eve.org/features.html#projections http://python-eve.org/features.html#projections