This presentation introduces smaws, a new Amazon Web Services (AWS) Software Development Kit (SDK) implementation for OCaml that leverages its type safety and effects-based concurrency to create a modern library for interfacing with AWS cloud computing services. smaws uses AWS’s Smithy interface definition language (IDL) to generate the SDK, taking advantage of an existing ecosystem of specifications and compliance tests. It explores the fundamental design challenges of creating developer-facing libraries in OCaml, where decisions about abstraction, validation, and ecosystem integration have long-standing implications for both usability and maintainability. We will also look at existing OCaml libraries in this space, and the relative merits of Smithy as a new IDL.