Flatcar Container Linux

Flatcar Container Linux is a CNCF incubating minimal, immutable Linux distribution designed for running containers. It provides automatic atomic updates through the Nebraska update server, ensuring nodes stay secure and consistent. Flatcar supports Kubernetes deployments on bare metal, cloud, and virtual environments with a focus on security and operational simplicity.

Flatcar Container Linux publishes 8 API contracts indexed on the APIs.io network, including Activity API, Apps API, Channels API, and 5 more. Tagged areas include Cloud-Native, Containers, Immutable Infrastructure, Incubating, and Linux.

The Flatcar Container Linux catalog on APIs.io includes 1 Spectral governance ruleset.

Flatcar Container Linux’s developer surface includes authentication, documentation, release notes, engineering blog, and 17 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

37.2/100 thin ▬ flat Agent 29/100 agent aware Front door AI 1/6 silent Heartbeat 64/100 alive self hosted · Apache-2.0 Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

AccessFreemiumSelf serve⚡ Free to try

1 published contract

Cloud-Native ContainersImmutable InfrastructureIncubating Linux Operating System

Kin Score

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

Composite quality — 37.2/100 · thin

Contract Quality 7.3 / 16

Developer Ergonomics 3.7 / 13

Access Clarity 1.1 / 13

Operational Transparency 3.0 / 8

Contract Governance 1.1 / 8

Discoverability 4.3 / 7

Regulatory Posture 1.8 / 15

Open Source Surface 10.0 / 10

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 29/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 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

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 applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 65 points between them, because both conditional facets apply and carry 35 points together. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 65% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Show this score on your site.

It updates itself when the score changes. Paste this where you link to your API docs:

<a href="https://apis.io/providers/flatcar-container-linux/"><img src="https://apis.io/badge/flatcar-container-linux/card.svg" alt="Flatcar Container Linux on APIs.io — Kin Score by API Evangelist"></a>

Other styles, a README pill and a shields.io endpoint are on the badge page.

Raise your score.

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

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 →
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 →
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0 Ask about this →
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document Ask about this →
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented) Ask about this →
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks Ask about this →

7 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 8.5 — up to +18.3 composite points Ask about this →
Developer Ergonomics scores 28.6 — up to +14.3 composite points Ask about this →
Contract Quality scores 44.8 — up to +13.8 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/flatcar-container-linux/apis.yml: open an issue on github.com/api-evangelist/flatcar-container-linux 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
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.

Standards implemented 1

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

OpenAPI

measured — observed by APIs.io (published)

APIs 8

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

Flatcar Container Linux Activity API

The Activity API from Flatcar Container Linux — 1 operation(s) for activity.

Flatcar Container Linux Apps API

The Apps API from Flatcar Container Linux — 17 operation(s) for apps.

Flatcar Container Linux Channels API

The Channels API from Flatcar Container Linux — 2 operation(s) for channels.

Flatcar Container Linux Config API

The Config API from Flatcar Container Linux — 1 operation(s) for config.

Flatcar Container Linux Health API

The Health API from Flatcar Container Linux — 1 operation(s) for health.

Flatcar Container Linux Instances API

The Instances API from Flatcar Container Linux — 1 operation(s) for instances.

Flatcar Container Linux Login API

The Login API from Flatcar Container Linux — 3 operation(s) for login.

Flatcar Container Linux Update API

The Update API from Flatcar Container Linux — 1 operation(s) for update.

Scroll for all 8

Open Collections 9

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Nebraska Activity API

OPEN COLLECTION

Nebraska Activity Apps API

OPEN COLLECTION

Nebraska Activity Channels API

OPEN COLLECTION

Nebraska Activity Config API

OPEN COLLECTION

Nebraska Activity Health API

OPEN COLLECTION

Nebraska Activity Instances API

OPEN COLLECTION

Nebraska Activity Login API

OPEN COLLECTION

Nebraska Activity Update API

OPEN COLLECTION

Nebraska

OPEN COLLECTION

Scroll for all 9

Flatcar Container Linux API pricing

Not yet checked against Flatcar Container Linux'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 Flatcar Container Linux's documentation. All 5 limits →

Pricing Plans 1

Published pricing tiers and plan structures.

Flatcar Container Linux Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Flatcar Container Linux Rate Limits

5 limits

RATE LIMITS

Data License 1

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

Flatcar Container Linux

2 quoted statements, read from Flatcar Container Linux's own page on 2026-11-09.

LICENSE

FinOps 1

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

Flatcar Container Linux Finops

FINOPS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs. Counts are the severity each rule declares, not results of running them.

Flatcar Container Linux API Rules

56 rules · 44 error-severity 10 warn-severity 2 info-severity

SPECTRAL

Security Posture 2

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

Flatcar Container Linux Authentication

apiKey/http · 3 schemes

SECURITY

Flatcar Container Linux Domain Security

TLSv1.3 · HSTS

SECURITY

Agentic Access (API Evangelist recommendations) 1

Recommended x-agentic-access execution contracts for AI agents.

Flatcar Container Linux Agentic Access

40 operations · 17 acting

AGENTIC

Resources

Documentation 2

Reference material describing how the API behaves

ContributionGuide

ContributionGuide

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 3

SDKs, sample code, and the tooling you integrate with

CodeOfConduct

CodeOfConduct

GitHubOrganization

GitHubOrganization

SourceCode

SourceCode

Access & Security 3

Authentication, authorization, and security posture

SecurityPolicy

SecurityPolicy

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 5

Status, limits, changes, and where to get help

RateLimits

IssueTracker

Releases

ReleaseNotes

Community

Commercial 4

Pricing, plans, and the legal terms of use

Plans

FinOps

License

DataLicense

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

NebraskaSource

NebraskaSource

Source (apis.yml)

aid: flatcar-container-linux
name: Flatcar Container Linux
description: Flatcar Container Linux is a CNCF incubating minimal, immutable Linux distribution designed for running containers.
  It provides automatic atomic updates through the Nebraska update server, ensuring nodes stay secure and consistent. Flatcar
  supports Kubernetes deployments on bare metal, cloud, and virtual environments with a focus on security and operational
  simplicity.
url: https://raw.githubusercontent.com/api-evangelist/flatcar-container-linux/refs/heads/main/apis.yml
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
  - openapi
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  gated: none
  gated_source:
  - onboarding
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-11-13'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/flatcar-container-linux.png
tags:
- Cloud-Native
- Containers
- Immutable Infrastructure
- Incubating
- Linux
- Operating System
tags_raw:
- Cloud Native
- Containers
- Immutable Infrastructure
- Incubating
- Linux
- Operating System
created: '2026-03-16'
modified: '2026-05-19'
specificationVersion: '0.23'
type: Index
access: Open Source
position: Producing
apis:
- aid: flatcar-container-linux:flatcar-container-linux-activity-api
  name: Flatcar Container Linux Activity API
  description: The Activity API from Flatcar Container Linux — 1 operation(s) for activity.
  humanURL: https://www.flatcar.org/docs/latest/nebraska/
  baseURL: https://nebraska.flatcar-linux.org/api
  tags:
  - Activity
  properties:
  - type: OpenAPI
    url: openapi/flatcar-container-linux-activity-api-openapi.yml
  - type: Documentation
    url: https://www.flatcar.org/docs/latest/nebraska/
  - type: SourceCode
    url: https://github.com/flatcar/nebraska
- aid: flatcar-container-linux:flatcar-container-linux-apps-api
  name: Flatcar Container Linux Apps API
  description: The Apps API from Flatcar Container Linux — 17 operation(s) for apps.
  humanURL: https://www.flatcar.org/docs/latest/nebraska/
  baseURL: https://nebraska.flatcar-linux.org/api
  tags:
  - Application
  tags_raw:
  - Apps
  properties:
  - type: OpenAPI
    url: openapi/flatcar-container-linux-apps-api-openapi.yml
  - type: Documentation
    url: https://www.flatcar.org/docs/latest/nebraska/
  - type: SourceCode
    url: https://github.com/flatcar/nebraska
- aid: flatcar-container-linux:flatcar-container-linux-channels-api
  name: Flatcar Container Linux Channels API
  description: The Channels API from Flatcar Container Linux — 2 operation(s) for channels.
  humanURL: https://www.flatcar.org/docs/latest/nebraska/
  baseURL: https://nebraska.flatcar-linux.org/api
  tags:
  - Channels
  properties:
  - type: OpenAPI
    url: openapi/flatcar-container-linux-channels-api-openapi.yml
  - type: Documentation
    url: https://www.flatcar.org/docs/latest/nebraska/
  - type: SourceCode
    url: https://github.com/flatcar/nebraska
- aid: flatcar-container-linux:flatcar-container-linux-config-api
  name: Flatcar Container Linux Config API
  description: The Config API from Flatcar Container Linux — 1 operation(s) for config.
  humanURL: https://www.flatcar.org/docs/latest/nebraska/
  baseURL: https://nebraska.flatcar-linux.org/api
  tags:
  - Config
  properties:
  - type: OpenAPI
    url: openapi/flatcar-container-linux-config-api-openapi.yml
  - type: Documentation
    url: https://www.flatcar.org/docs/latest/nebraska/
  - type: SourceCode
    url: https://github.com/flatcar/nebraska
- aid: flatcar-container-linux:flatcar-container-linux-health-api
  name: Flatcar Container Linux Health API
  description: The Health API from Flatcar Container Linux — 1 operation(s) for health.
  humanURL: https://www.flatcar.org/docs/latest/nebraska/
  baseURL: https://nebraska.flatcar-linux.org/api
  tags:
  - Health
  properties:
  - type: OpenAPI
    url: openapi/flatcar-container-linux-health-api-openapi.yml
  - type: Documentation
    url: https://www.flatcar.org/docs/latest/nebraska/
  - type: SourceCode
    url: https://github.com/flatcar/nebraska
- aid: flatcar-container-linux:flatcar-container-linux-instances-api
  name: Flatcar Container Linux Instances API
  description: The Instances API from Flatcar Container Linux — 1 operation(s) for instances.
  humanURL: https://www.flatcar.org/docs/latest/nebraska/
  baseURL: https://nebraska.flatcar-linux.org/api
  tags:
  - Instances
  properties:
  - type: OpenAPI
    url: openapi/flatcar-container-linux-instances-api-openapi.yml
  - type: Documentation
    url: https://www.flatcar.org/docs/latest/nebraska/
  - type: SourceCode
    url: https://github.com/flatcar/nebraska
- aid: flatcar-container-linux:flatcar-container-linux-login-api
  name: Flatcar Container Linux Login API
  description: The Login API from Flatcar Container Linux — 3 operation(s) for login.
  humanURL: https://www.flatcar.org/docs/latest/nebraska/
  baseURL: https://nebraska.flatcar-linux.org/api
  tags:
  - Login
  properties:
  - type: OpenAPI
    url: openapi/flatcar-container-linux-login-api-openapi.yml
  - type: Documentation
    url: https://www.flatcar.org/docs/latest/nebraska/
  - type: SourceCode
    url: https://github.com/flatcar/nebraska
- aid: flatcar-container-linux:flatcar-container-linux-update-api
  name: Flatcar Container Linux Update API
  description: The Update API from Flatcar Container Linux — 1 operation(s) for update.
  humanURL: https://www.flatcar.org/docs/latest/nebraska/
  baseURL: https://nebraska.flatcar-linux.org/api
  tags: []
  tags_raw:
  - Update
  properties:
  - type: OpenAPI
    url: openapi/flatcar-container-linux-update-api-openapi.yml
  - type: Documentation
    url: https://www.flatcar.org/docs/latest/nebraska/
  - type: SourceCode
    url: https://github.com/flatcar/nebraska
common:
- type: Plans
  url: plans/flatcar-container-linux-plans-pricing.yml
- type: RateLimits
  url: rate-limits/flatcar-container-linux-rate-limits.yml
- type: FinOps
  url: finops/flatcar-container-linux-finops.yml
- type: IssueTracker
  url: https://github.com/flatcar/nebraska/issues
- type: Releases
  url: https://github.com/flatcar/nebraska/releases
- type: SecurityPolicy
  url: https://github.com/flatcar/nebraska/blob/main/SECURITY.md
- type: CodeOfConduct
  url: https://github.com/flatcar/nebraska/blob/main/code-of-conduct.md
- type: ContributionGuide
  url: https://github.com/flatcar/nebraska/blob/main/CONTRIBUTING.md
- type: License
  name: Apache-2.0
  url: https://github.com/flatcar/nebraska/blob/main/LICENSE
- type: AgenticAccess
  url: agentic-access/flatcar-container-linux-agentic-access.yml
- type: DomainSecurity
  url: security/flatcar-container-linux-domain-security.yml
- type: Authentication
  url: authentication/flatcar-container-linux-authentication.yml
- type: Website
  url: https://www.flatcar.org
- type: Documentation
  url: https://www.flatcar.org/docs/latest/
- type: GitHubOrganization
  url: https://github.com/flatcar
- type: SourceCode
  url: https://github.com/flatcar/flatcar
- type: NebraskaSource
  url: https://github.com/flatcar/nebraska
- type: ReleaseNotes
  url: https://www.flatcar.org/releases/
- type: Community
  url: https://www.flatcar.org/community/
- url: https://www.flatcar.org/blog/index.xml
  type: Blog
- type: DataLicense
  url: data-license/flatcar-container-linux-data-license.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Flatcar Container Linux API — frequently asked questions

Does Flatcar Container Linux have an API?

Yes. APIs.io lists 8 APIs from Flatcar Container Linux, including Flatcar Container Linux Activity API, Flatcar Container Linux Apps API and Flatcar Container Linux Channels API, and 5 more.

Is there an OpenAPI specification for the Flatcar Container Linux API?

Yes. APIs.io indexes 8 OpenAPI specifications for Flatcar Container Linux, each linked for download from this page.

How do I authenticate with the Flatcar Container Linux API?

Flatcar Container Linux uses bearer-token authentication (apiKey/http · 3 schemes). The details are profiled on APIs.io as Flatcar Container Linux Authentication.

How much does the Flatcar Container Linux API cost?

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

Is the Flatcar Container Linux API ready for AI agents?

Flatcar Container Linux has a Kin Score of 37.2 out of 100 (thin) and an Agent Readiness score of 28.5 (agent-aware), 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

One button, every client — Claude, Cursor, VS Code and the rest.

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 →

Call it yourself

curl for this page

This provider

curl "https://apis.io/api/v1/providers/flatcar-container-linux"

All providers

curl "https://apis.io/api/v1/providers?limit=25"

Every operation they expose

curl "https://apis.io/api/v1/providers/flatcar-container-linux/operations?limit=25"

How their score was established

curl "https://apis.io/api/v1/providers/flatcar-container-linux/evidence"

Calls without X-API-Key need no key. Calls with it need a paid plan — get a key.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.