Modeling Services With Smithy IDL: From Interface Definitions to SDKs, Documentation & More

Smithy is AWS's Interface Definition Language (IDL), similar to ProtoBuf and OpenAPI. Unlike these tools, Smithy is protocol-agnostic and flexible enough to work with any protocol.

Smithy achieves this through specialized language features and a modular tooling framework. This allows protocol definitions and related tools — like validators and code generators — to exist as decoupled, reusable packages. These capabilities led us at Juspay to invest in Smithy and to develop our own code-generator plugin for Haskell: https://github.com/juspay/smithy-hs

This talk will explore Smithy's core concepts, show how to model services with it, and demonstrate how to leverage its plugin ecosystem to generate code artifacts.

• How Smithy IDL differs from protocol-specific IDLs like OpenAPI

• How to model services using Smithy's syntax and constructs

• Understanding Smithy's plugin ecosystem and how to leverage existing generators

• Our experience with building a codegen plugin for Smithy