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Spin

Spin is an open source framework by Fermyon for building and running fast, secure, and composable cloud microservices with WebAssembly. Spin provides a developer experience for creating event-driven serverless applications that compile to WebAssembly and run on any platform that supports the Spin runtime including local dev environments, Kubernetes (via SpinKube), and Fermyon Cloud.

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 Spin the way a machine reads it — 15 machine-readable artifacts across 5 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 — Spin scores 29.9/100 (thin), with a separate agent-readiness read of 3/100 (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 2026-08-17 · rubric v0.11.0
Composite quality — 29.9/100 · thin
Contract Quality 3.2 / 25
Developer Ergonomics 5.2 / 20
Commercial Clarity 3.2 / 20
Operational Transparency 4.4 / 13
Governance 8.3 / 12
Discoverability 5.6 / 10
Agent readiness — 3/100 · human only
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 10
MCP Server 0 / 12
Machine-Readable Auth 0 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling documented 3.5 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Spin Kin Score — API readiness rating by API Evangelist

Put this on your own site. The badge is drawn live from Spin's current Kin Score — paste it once and it updates itself every time the score is recomputed. It follows your visitor's light or dark setting, and it links back here so anyone who sees it can read the full breakdown.

<!-- Kin Score · API Evangelist -->
<a href="https://providers.apievangelist.com/providers/spin/"
   title="Spin on API Evangelist — API profile and Kin Score">
  <img src="https://apis.io/badge/spin.svg"
       alt="Spin Kin Score — API readiness rating by API Evangelist" width="150" height="150" loading="lazy">
</a>

More shapes, themes and sizes → · Score as JSON · How badges work

How we profile Spin

Each block below is one kind of artifact we hold for Spin. 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 5

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.

Spin HTTP Trigger API

The Spin HTTP Trigger API handles incoming HTTP requests and routes them to the appropriate Spin component. Components receive an HTTP request object and return an HTTP response...

Spin Key-Value Store API

The Spin Key-Value Store API provides Spin components with access to a persistent key-value storage service. Components read, write, and delete key-value pairs using the Spin SD...

Spin SQLite API

The Spin SQLite API provides Spin components with access to an embedded relational database. Components can execute SQL queries and statements using the Spin SDK's SQLite interf...

Spin Serverless AI API

The Spin Serverless AI API enables Spin components to run AI inference using built-in language model support (Llama 2, CodeLlama, etc.) via the Spin SDK's infer() function. Comp...

Spin Variables API

The Spin Variables API provides runtime access to application configuration variables defined in spin.toml. Variables can be required or optional with defaults, and can be marke...

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.

Spin 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.

Spin 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.

Spin Finops

FINOPS

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.

Spin Context

3 classes · 15 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.

Spin API Rules

5 rules · 4 warnings

SPECTRAL

Spin API Rules

7 rules · 2 errors · 5 warnings

SPECTRAL

JSON Schema 1

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.

Spin Application Manifest

4 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.

Spin Manifest 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.

Spin Manifest Example

2 fields

EXAMPLE

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.

Spin Domain Security

TLSv1.3 · DNSSEC

SECURITY

Resources

Every other property we hold for Spin — 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

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Build 2

SDKs, sample code, and the tooling you integrate with

Access & Security 1

Authentication, authorization, and security posture

Commercial 1

Pricing, plans, and the legal terms of use

Company 3

The organization behind the API

Other 1

Properties that don't map to a standard resource type

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

Where this information came from

This is an independent, third-party profile of Spin, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.

The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.

Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.

info@apievangelist.com · Read the full data-sourcing policy →
On a security or compliance team? Put security in the subject line and you will get a person, not a form — we will tell you exactly which public URLs this profile was built from.