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Smithy

Smithy is an open source, protocol-agnostic interface definition language (IDL) and toolchain developed at AWS for defining, validating, and generating API clients, servers, and documentation for any programming language. It powers the AWS SDK code generation pipeline and supports protocol-agnostic API modeling with traits, validators, and code generators. Smithy IDL 2.0 is the current stable version.

human only

Limited machine-readable signal and partial portal coverage — documentation a human can read, but little a machine or agent can consume without scraping.

Kin Score

API Evangelist profiles Smithy the way a machine reads it — 13 machine-readable artifacts across 2 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.

Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Smithy scores 37.6/100 (thin), with a separate agent-readiness read of 14/100 (human only). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.

Kin Score

This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 37.6/100 · thin
Contract Quality 3.8 / 25
Developer Ergonomics 4.3 / 20
Commercial Clarity 7.9 / 20
Operational Transparency 4.8 / 13
Governance 8.8 / 12
Discoverability 8.0 / 10
Agent readiness — 14/100 · human only
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 15
MCP Server 0 / 12
Machine-Readable Auth 0 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 7 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3

How we profile Smithy

Each block below is one kind of artifact we hold for Smithy. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.

APIs 2

Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.

Individual APIs this provider publishes, each with its own machine-readable definition.

Smithy IDL

The Smithy Interface Definition Language (IDL) is a specification for defining API models using shapes and traits. Models can be written in the Smithy IDL syntax or the JSON AST...

Smithy CLI

The Smithy CLI is a command-line tool for building, validating, diffing, and transforming Smithy models. It can generate JSON AST representations, run model validation, perform ...

Pricing Plans 1

Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.

Published pricing tiers and plan structures.

Smithy Plans Pricing

3 plans

PLANS

Rate Limits 1

Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.

Documented rate limits and quota policies.

Smithy Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.

Cost, billing, and metering signals for API financial operations.

Semantic Vocabularies 1

JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.

JSON-LD contexts and semantic vocabularies used across these APIs.

Smithy Context

26 classes · 0 properties

JSON-LD

Spectral Rules 2

Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.

Smithy API Rules

5 rules · 4 warnings

SPECTRAL

Smithy API Rules

5 rules · 1 errors · 3 warnings

SPECTRAL

JSON Schema 2

Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.

Standalone JSON Schema definitions for this provider's data models.

Smithy Model (JSON AST)

3 properties

JSON SCHEMA

Smithy Shape

12 properties

JSON SCHEMA

JSON Structure 1

JSON Structure captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.

JSON Structure definitions describing this provider's data shapes.

Smithy Model Structure

0 properties

JSON STRUCTURE

Examples 1

Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.

Example request and response payloads for these APIs.

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Smithy Domain Security

TLSv1.3

SECURITY

Resources

Every other property we hold for Smithy — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.

Get Started 1

Portal, sign-up, and the first successful call

Documentation 2

Reference material describing how the API behaves

Access & Security 1

Authentication, authorization, and security posture

Company 2

The organization behind the API

Other 2

Properties that don't map to a standard resource type

← All providers · Data indexed from github.com/api-evangelist/smithy · machine-readable index on apis.io