Smithy

Spec sheet

Purpose

Smithy is an open-source interface definition language for modeling services and SDKs.Read 9 Oct 2026 · smithy.io

Product

Smithy is an open-source, protocol-agnostic interface definition language and toolset for defining APIs and generating clients, servers, and documentation.Read 4 Oct 2026 · smithy.io

Intended users

Smithy is presented for teams defining service APIs and generating SDKs, server code, and documentation across programming languages.Read 4 Oct 2026 · smithy.io

Integrations

Smithy build configurations can load extensions and code generators through Maven dependencies and plugins, including AWS-specific dependencies and an OpenAPI generator.Read 4 Oct 2026 · smithy.io

Security

The Smithy CLI installation guide says release archives are PGP-signed and hashed, and describes verifying signatures and checksums.Read 9 Oct 2026 · smithy.io

Support

The CLI guide directs users with suggestions or issues to create an issue in the Smithy GitHub repository.Read 4 Oct 2026 · smithy.io

License

The site identifies Smithy as open source under the Apache 2.0 license.Read 9 Oct 2026 · smithy.io

API protocols

The same service model can support REST JSON, RPC v2 CBOR, AWS JSON, and AWS Query/XML protocols.Read 4 Oct 2026 · smithy.io

AWS integrations

Smithy documents integrations with AWS services and tools including API Gateway, CloudFormation, and AWS SDKs.Read 9 Oct 2026 · smithy.io

AWS use

Smithy says it was created and is used at AWS, and that it powers AWS APIs and SDKs.Read 4 Oct 2026 · smithy.io

CLI

The Smithy CLI can build models, run ad hoc validation, compare models, and query models without requiring users to set up Java or Smithy Gradle Plugins.Read 4 Oct 2026 · smithy.io

CLI platforms

The Smithy CLI is supported on macOS for x86 and ARM, Linux for x86 and ARM, and Windows x64.Read 9 Oct 2026 · smithy.io

Client languages

The site lists client SDKs for TypeScript, Python, Go, Rust, Kotlin, Swift, Java, Scala, Ruby, and Dafny.Read 9 Oct 2026 · smithy.io

Code generation

A single Smithy model can generate type-safe clients, servers, documentation, OpenAPI, and JSON Schema.Read 9 Oct 2026 · smithy.io

Community and maintenance

The site says Smithy is maintained by AWS and the open-source community and links to community resources and GitHub issues.Read 9 Oct 2026 · smithy.io

Download verification

Smithy CLI release archives are PGP-signed and hashed, and the installation guide describes verifying their signatures and checksums.Read 4 Oct 2026 · smithy.io

Governance

Smithy validates model standards during smithy build and checks revisions for backward compatibility.Read 9 Oct 2026 · smithy.io

Modeling

Smithy supports resource-based API modeling, which can be used to generate artifacts including CloudFormation schemas, SDKs, and documentation.Read 4 Oct 2026 · smithy.io

Protocols

Smithy describes support for REST JSON, RPC v2 CBOR, AWS JSON, and AWS Query protocols.Read 9 Oct 2026 · smithy.io

Server languages

The site lists server support for TypeScript, Java, Python, Go, and Rust.Read 9 Oct 2026 · smithy.io

Supported CLI platforms

The Smithy CLI is supported on macOS x86 and ARM, Linux x86 and ARM, and Windows x64.Read 4 Oct 2026 · smithy.io

Where Specifiction places it

• API Design Tools#24 of 267.1