Spin website screenshot

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.

Spin publishes 5 APIs on the APIs.io network. Tagged areas include Cloud-Native, Microservices, Serverless, and WebAssembly.

The Spin catalog on APIs.io includes 1 JSON-LD context and 2 Spectral governance rulesets.

Spin’s developer surface includes documentation, getting-started guide, release notes, engineering blog, and 17 more developer resources.

🌐 Visit website 📡 Source on GitHub
31.1/100 thin ▬ flat Agent 3/100 human only self hosted · Apache-2.0 Full breakdown ↓
scored 2026-09-14 · rubric v0.22.0
AccessFreemium
5 APIs
Cloud-NativeMicroservicesServerlessWebAssembly

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-09-14 · rubric v0.22.0
Composite quality — 31.1/100 · thin
Contract Quality 2.4 / 23
Developer Ergonomics 2.8 / 18
Access Clarity 2.8 / 18
Operational Transparency 4.9 / 12
Contract Governance 3.1 / 11
Discoverability 5.0 / 9
Open Source Surface 10.0 / 10
Agent readiness — 3/100 · human only
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 10
Documented Reversibility 0 / 6
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 7 / 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
Delegated User Identity 0 / 6
Protected Resource Metadata 0 / 5
Registration Without a Human 0 / 6
Agentic Commerce Well-Known Document 0 / 5
Open Source Surface applies to this provider. This product is open source and we read its repository directly, so Open Source Surface carries 10 points of the composite. It is scored from what the repository actually publishes — a security policy, a contribution guide, a release history, a code of conduct — read live from the provider rather than inferred from our own catalog pointers. This facet adds; nothing was taken away to make room for it. An open-source project is not excused from the commercial facets, because exemption would strip it of the points it does earn. If we have the wrong repository, or this product is not open source, say so on your provider repo and we will drop the facet rather than have you publish against it.
Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.
The six quality facets above are damped to 90 points between them, because the conditional facet above carries the other 10. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 90% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/spin: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 5

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

Published pricing tiers and plan structures.

Spin Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Spin Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Spin Finops

FINOPS

Semantic Vocabularies 1

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

Spin Context

3 classes · 15 properties

JSON-LD

Spectral Rules 2

Spectral governance rulesets for linting and validating these APIs.

Spin API Rules

5 rules · 4 warnings 1 info

SPECTRAL

Spin API Rules

7 rules · 2 errors 5 warnings

SPECTRAL

JSON Schema 1

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

Spin Application Manifest

4 properties

JSON SCHEMA

JSON Structure 1

JSON Structure definitions describing this provider's data shapes.

Spin Manifest Structure

0 properties

JSON STRUCTURE

Examples 1

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.

Spin Domain Security

TLSv1.3 · DNSSEC

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

GettingStarted
GettingStarted

Documentation 3

Reference material describing how the API behaves

ContributionGuide
ContributionGuide
 JSONSchema
JSONSchema
 Documentation
Documentation

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

SpectralRules
SpectralRules
 Vocabulary
Vocabulary

Build 3

SDKs, sample code, and the tooling you integrate with

CodeOfConduct
CodeOfConduct
 GitHubOrganization
GitHubOrganization
 GitHubRepository
GitHubRepository

Access & Security 2

Authentication, authorization, and security posture

SecurityPolicy
SecurityPolicy
 DomainSecurity
DomainSecurity

Operate 5

Status, limits, changes, and where to get help

IssueTracker
IssueTracker
 ReleaseNotes
ReleaseNotes
 RoadMap
RoadMap
 Community
Community
 Discord
Discord

Commercial 1

Pricing, plans, and the legal terms of use

License
License

Company 3

The organization behind the API

LinkedIn
LinkedIn
 Website
Website
 Blog
Blog

Other 1

Properties that don't map to a standard resource type

X
X

Source (apis.yml)

apis.yml Raw ↑ 
aid: spin
name: Spin
description: 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.
type: Index
deliveryModel:
  model: self-hosted
  license: Apache-2.0
  open_source: true
  commercial: false
  callable_host: false
  label: Self-hosted open source · you run it yourself
  confidence: high
  source:
  - license
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/spin.png
tags:
- Cloud-Native
- Microservices
- Serverless
- WebAssembly
tags_raw:
- Cloud Native
- Microservices
- Serverless
- WebAssembly
url: https://raw.githubusercontent.com/api-evangelist/spin/refs/heads/main/apis.yml
created: '2026-03-26'
modified: '2026-05-02'
specificationVersion: '0.23'
apis:
- aid: spin:spin-http-trigger-api
  name: Spin HTTP Trigger API
  description: 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. Supported via the Spin SDK in Rust, Go, Python,
    JavaScript, and other languages that target WASI.
  humanURL: https://spinframework.dev/v3/http-trigger
  tags:
  - HTTP
  - Trigger
  - WebAssembly
  properties:
  - type: Documentation
    url: https://spinframework.dev/v3/http-trigger
  - type: GitHubRepository
    url: https://github.com/fermyon/spin
- aid: spin:spin-key-value-api
  name: Spin Key-Value Store API
  description: 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 SDK. The underlying store can be an in-memory store
    (for development), Redis, or cloud-managed storage depending on the deployment target.
  humanURL: https://spinframework.dev/v3/kv-store-api
  tags:
  - Key-Value
  - Storage
  - WebAssembly
  properties:
  - type: Documentation
    url: https://spinframework.dev/v3/kv-store-api
  - type: GitHubRepository
    url: https://github.com/fermyon/spin
- aid: spin:spin-sqlite-api
  name: Spin SQLite API
  description: 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 interface, enabling structured data persistence within
    Spin applications.
  humanURL: https://spinframework.dev/v3/sqlite-api
  tags:
  - Database
  - SQLite
  - Storage
  - WebAssembly
  properties:
  - type: Documentation
    url: https://spinframework.dev/v3/sqlite-api
  - type: GitHubRepository
    url: https://github.com/fermyon/spin
- aid: spin:spin-serverless-ai-api
  name: Spin Serverless AI API
  description: 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. Components must declare the ai_models they need in spin.toml.
    Supported on Fermyon Cloud and SpinKube deployments.
  humanURL: https://spinframework.dev/v3/serverless-ai-tutorial
  tags:
  - Artificial Intelligence
  - LLM
  - Machine-Learning
  - WebAssembly
  tags_raw:
  - AI
  - LLM
  - Machine Learning
  - WebAssembly
  properties:
  - type: Documentation
    url: https://spinframework.dev/v3/serverless-ai-tutorial
  - type: GitHubRepository
    url: https://github.com/fermyon/spin
- aid: spin:spin-variables-api
  name: Spin Variables API
  description: 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 marked as secrets. At runtime, variables are resolved
    from environment variables, Vault, or other configured providers.
  humanURL: https://spinframework.dev/v3/variables
  tags:
  - Configuration
  - Variables
  - WebAssembly
  properties:
  - type: Documentation
    url: https://spinframework.dev/v3/variables
  - type: GitHubRepository
    url: https://github.com/fermyon/spin
common:
- type: IssueTracker
  url: https://github.com/fermyon/spin/issues
- type: SecurityPolicy
  url: https://github.com/spinframework/spin/blob/main/SECURITY.md
- type: CodeOfConduct
  url: https://github.com/spinframework/spin/blob/main/CODE_OF_CONDUCT.md
- type: ContributionGuide
  url: https://github.com/spinframework/spin/blob/main/CONTRIBUTING.md
- type: License
  name: Apache-2.0
  url: https://github.com/fermyon/spin/blob/main/LICENSE
- type: DomainSecurity
  url: security/spin-domain-security.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/fermyon
- type: JSONSchema
  url: json-schema/spin-manifest.json
- type: SpectralRules
  url: rules/spin-rules.yml
- type: Vocabulary
  url: vocabulary/spin-vocabulary.yml
- type: Website
  url: https://spinframework.dev/
- type: Documentation
  url: https://spinframework.dev/v3/
- type: GettingStarted
  url: https://spinframework.dev/v3/quickstart
- type: GitHubOrganization
  url: https://github.com/fermyon
- type: GitHubRepository
  url: https://github.com/fermyon/spin
- type: ReleaseNotes
  url: https://github.com/fermyon/spin/releases
- type: RoadMap
  url: https://github.com/fermyon/spin/blob/main/ROADMAP.md
- type: Community
  url: https://www.fermyon.com/community
- type: Blog
  url: https://www.fermyon.com/blog
- type: Discord
  url: https://discord.gg/AAFNfS7NGf
- type: X
  url: https://twitter.com/fermyon
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
x-parent: fermyon
x-relationship: product

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