Caddy

Caddy is a modern, extensible, open-source web server and reverse proxy written in Go that provides automatic HTTPS via Let's Encrypt, a dynamic JSON-based admin API, a human-friendly Caddyfile configuration format, and a modular architecture with a rich ecosystem of plugins for authentication, observability, and custom behavior.

Caddy is listed with 6 APIs on the APIs.io network, including Adapt API, Configuration API, Lifecycle API, and 3 more. Tagged areas include Automatic HTTPS, Go, Load Balancer, Reverse Proxy, and TLS.

The Caddy catalog on APIs.io includes 1 Spectral governance ruleset.

Caddy’s developer surface includes documentation and 15 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

27.3/100 thin ▬ flat Agent 18/100 agent aware Front door AI 1/6 silent Heartbeat 100/100 alive self hosted · Apache-2.0 Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessFreemium

6 APIs

Automatic HTTPSGo Load Balancer Reverse Proxy TLS Web Server

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 27.3/100 · thin

Contract Quality 5.6 / 16

Developer Ergonomics 2.8 / 13

Access Clarity 1.0 / 13

Operational Transparency 3.1 / 8

Contract Governance 1.1 / 8

Discoverability 4.1 / 7

Regulatory Posture 0.9 / 15

Open Source Surface 5.0 / 10

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 18/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 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 0 / 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/.

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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
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)
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)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link

10 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 7.9 — up to +18.4 composite points
Contract Quality scores 34.2 — up to +16.5 composite points
Developer Ergonomics scores 21.4 — up to +15.7 composite points

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.

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/caddy/apis.yml: open an issue on github.com/api-evangelist/caddy 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
Network Edge (CDN, networking, peering, edge compute)	standard	50.5	-	-
Cisco DevNet Ecosystem (builders on Meraki, Catalyst, ISE, ThousandEyes, Splunk)	standard	50.5	-	-
Docker Hub Verified Publishers + Official Images	standard	50.5	-	-

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 6

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

Caddy Admin API

Caddy exposes a RESTful administration API on localhost:2019 by default for dynamically loading and modifying server configuration at runtime without restarts. Endpoints support...

Caddy Adapt API

The Adapt API from Caddy — 1 operation(s) for adapt.

Caddy Configuration API

The Configuration API from Caddy — 1 operation(s) for configuration.

Caddy Lifecycle API

The Lifecycle API from Caddy — 2 operation(s) for lifecycle.

Caddy PKI API

The PKI API from Caddy — 2 operation(s) for pki.

Caddy Reverse Proxy API

The Reverse Proxy API from Caddy — 1 operation(s) for reverse proxy.

Open Collections 6

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

Caddy Admin Adapt API

OPEN COLLECTION

Caddy Admin Adapt Configuration API

OPEN COLLECTION

Caddy Admin Adapt Lifecycle API

OPEN COLLECTION

Caddy Admin Adapt PKI API

OPEN COLLECTION

Caddy Admin Adapt Reverse Proxy API

OPEN COLLECTION

Caddy Admin API

OPEN COLLECTION

Caddy API pricing

Not yet checked against Caddy'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 Caddy's documentation. All 5 limits →

Pricing Plans 1

Published pricing tiers and plan structures.

Caddy Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Caddy Rate Limits

5 limits

RATE LIMITS

Service Levels 1

Uptime the provider promises or reports, as SLA4OAI. Read from its own pages; APIs.io runs no monitors.

Caddy

SLA

FinOps 1

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

Caddy Finops

FINOPS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Caddy API Rules

36 rules · 33 errors 1 warnings 2 info

SPECTRAL

Security Posture 1

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

Caddy Domain Security

TLSv1.3 · DMARC

SECURITY

Agentic Access 1

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

Caddy Agentic Access

11 operations · 7 acting · 1 human-in-the-loop

11 operations · 7 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 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

SecurityPolicy

SecurityPolicy

DomainSecurity

DomainSecurity

Operate 4

Status, limits, changes, and where to get help

RateLimits

IssueTracker

Releases

Community Forum

Commercial 3

Pricing, plans, and the legal terms of use

Plans

Plans

FinOps

FinOps

License

License

Company 1

The organization behind the API

Website

Website

Other 2

Properties that don't map to a standard resource type

Download

Download

Sponsors

Source (apis.yml)

aid: caddy
name: Caddy
description: Caddy is a modern, extensible, open-source web server and reverse proxy written in Go that provides automatic
  HTTPS via Let's Encrypt, a dynamic JSON-based admin API, a human-friendly Caddyfile configuration format, and a modular
  architecture with a rich ecosystem of plugins for authentication, observability, and custom behavior.
type: Index
kind: opensource
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: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: low
  try_now_blocked_by: loopback
  source:
  - plans
  - security
  generated: '2026-11-06'
  method: derived
position: Consuming
access: Open Source
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/caddy.png
tags:
- Automatic HTTPS
- Go
- Load Balancer
- Reverse Proxy
- TLS
- Web Server
url: https://raw.githubusercontent.com/api-evangelist/caddy/refs/heads/main/apis.yml
created: '2026-03-27'
modified: '2026-05-19'
specificationVersion: '0.23'
apis:
- aid: caddy:caddy-admin-api
  name: Caddy Admin API
  description: Caddy exposes a RESTful administration API on localhost:2019 by default for dynamically loading and modifying
    server configuration at runtime without restarts. Endpoints support loading full JSON configs, traversing and mutating
    specific config paths, adapting Caddyfile to JSON, and querying PKI and reverse proxy state.
  humanURL: https://caddyserver.com/docs/api
  baseURL: http://localhost:2019
  tags:
  - Admin API
  - Configuration
  - REST
  properties:
  - type: Documentation
    url: https://caddyserver.com/docs/api
  - type: JSON Config Structure
    url: https://caddyserver.com/docs/json/
  - type: Modules Reference
    url: https://caddyserver.com/docs/modules/
  - type: API Tutorial
    url: https://caddyserver.com/docs/api-tutorial
  x-features:
  - POST /load for full config replacement
  - GET/POST/PUT/PATCH/DELETE /config/[path] for granular updates
  - POST /adapt to convert Caddyfile to JSON without loading
  - POST /stop for graceful shutdown
  - GET /pki/ca/{id} for internal CA inspection
  - GET /reverse_proxy/upstreams for upstream status
  - ETag and If-Match concurrency control
  x-use-cases:
  - Dynamic configuration in orchestrated environments
  - Multi-tenant SaaS with per-tenant routes
  - Zero-downtime config changes
  - Integration with service discovery
  - Observability of upstream health
- aid: caddy:caddy-adapt-api
  name: Caddy Adapt API
  description: The Adapt API from Caddy — 1 operation(s) for adapt.
  humanURL: https://caddyserver.com/
  baseURL: http://localhost:2019
  tags:
  - Adapt
  properties:
  - type: OpenAPI
    url: openapi/caddy-adapt-api-openapi.yml
  - type: Documentation
    url: https://caddyserver.com/docs/
  - type: GettingStarted
    url: https://caddyserver.com/docs/getting-started
  - type: GitHubRepository
    url: https://github.com/caddyserver/caddy
  - type: Download
    url: https://caddyserver.com/download
- aid: caddy:caddy-configuration-api
  name: Caddy Configuration API
  description: The Configuration API from Caddy — 1 operation(s) for configuration.
  humanURL: https://caddyserver.com/
  baseURL: http://localhost:2019
  tags:
  - Configuration
  properties:
  - type: OpenAPI
    url: openapi/caddy-configuration-api-openapi.yml
  - type: Documentation
    url: https://caddyserver.com/docs/
  - type: GettingStarted
    url: https://caddyserver.com/docs/getting-started
  - type: GitHubRepository
    url: https://github.com/caddyserver/caddy
  - type: Download
    url: https://caddyserver.com/download
- aid: caddy:caddy-lifecycle-api
  name: Caddy Lifecycle API
  description: The Lifecycle API from Caddy — 2 operation(s) for lifecycle.
  humanURL: https://caddyserver.com/
  baseURL: http://localhost:2019
  tags:
  - Lifecycle
  properties:
  - type: OpenAPI
    url: openapi/caddy-lifecycle-api-openapi.yml
  - type: Documentation
    url: https://caddyserver.com/docs/
  - type: GettingStarted
    url: https://caddyserver.com/docs/getting-started
  - type: GitHubRepository
    url: https://github.com/caddyserver/caddy
  - type: Download
    url: https://caddyserver.com/download
- aid: caddy:caddy-pki-api
  name: Caddy PKI API
  description: The PKI API from Caddy — 2 operation(s) for pki.
  humanURL: https://caddyserver.com/
  baseURL: http://localhost:2019
  tags:
  - PKI
  properties:
  - type: OpenAPI
    url: openapi/caddy-pki-api-openapi.yml
  - type: Documentation
    url: https://caddyserver.com/docs/
  - type: GettingStarted
    url: https://caddyserver.com/docs/getting-started
  - type: GitHubRepository
    url: https://github.com/caddyserver/caddy
  - type: Download
    url: https://caddyserver.com/download
- aid: caddy:caddy-reverse-proxy-api
  name: Caddy Reverse Proxy API
  description: The Reverse Proxy API from Caddy — 1 operation(s) for reverse proxy.
  humanURL: https://caddyserver.com/
  baseURL: http://localhost:2019
  tags:
  - Reverse Proxy
  properties:
  - type: OpenAPI
    url: openapi/caddy-reverse-proxy-api-openapi.yml
  - type: Documentation
    url: https://caddyserver.com/docs/
  - type: GettingStarted
    url: https://caddyserver.com/docs/getting-started
  - type: GitHubRepository
    url: https://github.com/caddyserver/caddy
  - type: Download
    url: https://caddyserver.com/download
common:
- type: Plans
  url: plans/caddy-plans-pricing.yml
- type: RateLimits
  url: rate-limits/caddy-rate-limits.yml
- type: FinOps
  url: finops/caddy-finops.yml
- type: IssueTracker
  url: https://github.com/caddyserver/caddy/issues
- type: Releases
  url: https://github.com/caddyserver/caddy/releases
- type: SecurityPolicy
  url: https://github.com/caddyserver/caddy/blob/master/.github/SECURITY.md
- type: ContributionGuide
  url: https://github.com/caddyserver/caddy/blob/master/.github/CONTRIBUTING.md
- type: License
  name: Apache-2.0
  url: https://github.com/caddyserver/caddy/blob/master/LICENSE
- type: AgenticAccess
  url: agentic-access/caddy-agentic-access.yml
- type: DomainSecurity
  url: security/caddy-domain-security.yml
- type: Website
  url: https://caddyserver.com/
- type: Documentation
  url: https://caddyserver.com/docs/
- type: GitHubOrganization
  url: https://github.com/caddyserver
- type: Community Forum
  url: https://caddy.community/
- type: Download
  url: https://caddyserver.com/download
- type: Sponsors
  url: https://github.com/sponsors/mholt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Caddy API — frequently asked questions

Does Caddy have an API?

Yes. APIs.io lists 6 APIs from Caddy, including Caddy Admin API, Caddy Adapt API and Caddy Configuration API, and 3 more.

Is there an OpenAPI specification for the Caddy API?

Yes. APIs.io indexes 5 OpenAPI specifications for Caddy, each linked for download from this page.

How much does the Caddy API cost?

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

Is the Caddy API ready for AI agents?

Caddy has a Kin Score of 27.3 out of 100 (thin) and an Agent Readiness score of 18.2 (agent-aware), scored by API Evangelist on 2026-11-06.

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 →

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Every operation they expose

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How their score was established

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