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 is listed with 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 22 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

29.8/100 thin ▬ flat Agent 1/100 human only Front door AI 2/6 trace self hosted · Apache-2.0 Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

AccessFreemium

5 APIs

Cloud-Native Microservices Serverless WebAssembly

Kin Score

Kin Score How this is scored →
scored 2026-11-13 · rubric v0.28.0

Composite quality — 29.8/100 · thin

Contract Quality 2.0 / 19

Developer Ergonomics 2.7 / 15

Access Clarity 1.9 / 15

Operational Transparency 3.9 / 10

Contract Governance 2.5 / 9

Discoverability 4.0 / 8

Regulatory Posture 1.6 / 15

Open Source Surface 10.0 / 10

Agent readiness — 1/100 · 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

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

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 75 points between them, because both conditional facets apply and carry 25 points together. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Machine-Readable Contract +18 pts — api_specs includes an OpenAPI document Ask about this →
MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship Ask about this →
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author Ask about this →
Machine-Readable Auth +10 pts — a served openid-configuration/oauth-authorization-server carrying `issuer` (served), else the securitySchemes class in the provider OpenAPIs — bound (mutualTLS, DPoP, Signature) > negotiable (oauth2 authorizationCode/clientCredentials, openIdConnect) > bearer (http bearer, apiKey) Ask about this →
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented) Ask about this →
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes Ask about this →

12 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 10.7 — up to +22.3 composite points Ask about this →
Access Clarity scores 12.8 — up to +17.4 composite points Ask about this →
Developer Ergonomics scores 17.9 — up to +16.4 composite points Ask about this →

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Not sure how this applies to your stack? Ask about any one item. Kin Lane reads every question, looks at your profile and your situation, and replies with what a fix would take — scoped to that one area, priced up front, yours whether you ship it or not. Ask a question →

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 the provider profile at artifacts.apis.io/spin/apis.yml: open an issue on github.com/api-evangelist/spin to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Cloud Native (Kubernetes, CNCF, FinOps)	standard	40.9 (thin)	-	-
OpenSSF Best Practices Badge Holders	standard	40.9 (thin)	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

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...

Spin API pricing

Not yet checked against Spin's own pricing page. Compiled by API Evangelist on 2026-05-04; confirm before you rely on a figure. A free plan or tier is listed.

Plan	Price
Free freemium	Free
Professional paid	Free
Enterprise enterprise	—

Plan details, limits and sources →

Rate limits

Free Tier Default: 10 requests per minute
Free Tier Monthly Quota: 1000 requests per month
Professional Tier Default: 100 requests per minute

Compiled by API Evangelist, not yet checked against Spin's documentation. All 5 limits →

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

Terms of Service 1

What its API terms permit and prohibit, quoted from its own page.

Spin

2 quoted statements, read from Spin's own page on 2026-11-10.

TERMS

Data License 1

How its data and outputs may be reused, quoted from its own terms.

Spin

2 quoted statements, read from Spin's own page on 2026-11-10.

LICENSE

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. Counts are the severity each rule declares, not results of running them.

Spin — jsonschema rules

5 rules · 4 warn-severity 1 info-severity

SPECTRAL

Spin API Rules

7 rules · 2 error-severity 5 warn-severity

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 6

Status, limits, changes, and where to get help

RateLimits

IssueTracker

ReleaseNotes

RoadMap

Community

Discord

Commercial 5

Pricing, plans, and the legal terms of use

Plans

FinOps

License

UsageTerms

DataLicense

Company 3

The organization behind the API

LinkedIn

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Source (apis.yml)

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: low
  source:
  - plans
  - security
  generated: '2026-11-13'
  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 Store
  - Storage
  - WebAssembly
  tags_raw:
  - 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
  - Machine-Learning
  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: Plans
  url: plans/spin-plans-pricing.yml
- type: RateLimits
  url: rate-limits/spin-rate-limits.yml
- type: FinOps
  url: finops/spin-finops.yml
- 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
- type: UsageTerms
  url: terms/spin-terms-of-service.yml
- type: DataLicense
  url: data-license/spin-data-license.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
x-parent: fermyon
x-relationship: product

Spin API — frequently asked questions

Does Spin have an API?

Yes. APIs.io lists 5 APIs from Spin, including Spin HTTP Trigger API, Spin Key-Value Store API and Spin SQLite API, and 2 more.

How much does the Spin API cost?

APIs.io lists 3 pricing plans for Spin, with each plan's price, limits and inclusions under Pricing on this page.

Is the Spin API ready for AI agents?

Spin has a Kin Score of 29.8 out of 100 (thin) and an Agent Readiness score of 0.6 (human-only), scored by API Evangelist on 2026-11-13.

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

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https://apis.io/mcp

Tools for providers

9 MCP tools reach this

find_providersBrowse and filter every provider in the catalog.
get_provider_artifactsEvery artifact this provider publishes, grouped by type.
get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
get_provider_ratingPRO — composite, band, trend and facet scores.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

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