Connexion

Connexion is an open source Python framework that automatically handles HTTP requests based on OpenAPI specifications. Connexion 3 provides AsyncApp, FlaskApp, and ConnexionMiddleware as primary entry points, with built-in routing, request and response validation, parameter parsing, security enforcement, content negotiation, error handling, lifespan, and Swagger UI integration. Connexion takes a contract-first, design-first approach: the OpenAPI specification is the source of truth and Python handlers are resolved from operationId or via configurable resolvers.

Connexion publishes 2 APIs on the APIs.io network. Tagged areas include API Design, ASGI, Design-First, Flask, and OpenAPI.

Connexion’s developer surface includes documentation, changelog, engineering blog, and 7 more developer resources.

🌐 Visit website 📡 Source on GitHub

23.8/100 emerging ▬ flat Agent 3/100 human only Full breakdown ↓
scored 2026-07-28 · rubric v0.6

AccessFreemium

2 APIs

API DesignASGIDesign-FirstFlaskOpenAPIPythonValidationWSGI

Kin Score

Kin Score How this is scored →
scored 2026-07-28 · rubric v0.6

Composite quality — 23.8/100 · emerging

Contract Quality 0.0 / 25

Developer Ergonomics 2.2 / 20

Commercial Clarity 7.9 / 20

Operational Transparency 6.8 / 13

Governance 0.0 / 12

Discoverability 6.9 / 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 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

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/connexion: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 2

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

Rate Limits 1

Documented rate limits and quota policies.

Connexion Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Build 2

SDKs, sample code, and the tooling you integrate with

GitHubRepository

GitHubRepository

GitHubOrganization

GitHubOrganization

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

Issue Tracker

Issue Tracker

ChangeLog

ChangeLog

Commercial 1

Pricing, plans, and the legal terms of use

License

License

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

PyPI

PyPI

Source (apis.yml)

aid: connexion
url: https://raw.githubusercontent.com/api-evangelist/connexion/refs/heads/main/apis.yml
name: Connexion
kind: opensource
description: 'Connexion is an open source Python framework that automatically handles HTTP requests based on OpenAPI specifications.
  Connexion 3 provides AsyncApp, FlaskApp, and ConnexionMiddleware as primary entry points, with built-in routing, request
  and response validation, parameter parsing, security enforcement, content negotiation, error handling, lifespan, and Swagger
  UI integration. Connexion takes a contract-first, design-first approach: the OpenAPI specification is the source of truth
  and Python handlers are resolved from operationId or via configurable resolvers.'
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/connexion.png
tags:
- API Design
- ASGI
- Design-First
- Flask
- OpenAPI
- Python
- Validation
- WSGI
created: '2026-03-25'
modified: '2026-04-28'
specificationVersion: '0.19'
apis:
- aid: connexion:framework
  name: Connexion Python Framework
  description: Connexion is a contract-first Python web framework that loads an OpenAPI specification and routes requests
    to Python handlers based on operationId. It performs request validation, parameter parsing, and response validation against
    the specification, with first-class support for security schemes and Swagger UI.
  humanURL: https://connexion.readthedocs.io/en/latest/
  baseURL: https://connexion.readthedocs.io
  tags:
  - Framework
  - OpenAPI
  - Python
  - Validation
  properties:
  - type: Documentation
    url: https://connexion.readthedocs.io/en/latest/
  - type: Documentation
    url: https://connexion.readthedocs.io/en/latest/quickstart.html
  - type: GitHubRepository
    url: https://github.com/spec-first/connexion
  - type: License
    url: https://github.com/spec-first/connexion/blob/main/LICENSE
  - type: Issue Tracker
    url: https://github.com/spec-first/connexion/issues
  x-features:
  - AsyncApp, FlaskApp, and ConnexionMiddleware entry points
  - Native ASGI server support and Flask compatibility
  - Automatic routing from operationId via RestyResolver
  - Request and response validation against OpenAPI
  - Security middleware honoring OpenAPI security schemes
  - Swagger UI mounted from the framework
  - Pythonic snake_case parameter conversion
  - Strict parameter validation modes
  x-useCases:
  - Build Python APIs from an OpenAPI 3.x specification
  - Migrate Flask applications to a contract-first model
  - Add request and response validation to an existing ASGI app
  - Generate Swagger UI alongside your API automatically
  - Compose multiple OpenAPI specifications under a single app
- aid: connexion:middleware
  name: Connexion Middleware Stack
  description: Connexion 3 introduces a stack of pluggable ASGI middlewares that handle exceptions, server errors, lifespan,
    security, routing, request validation, response validation, Swagger UI, and context propagation. The middleware stack
    can be applied to any ASGI or WSGI application via ConnexionMiddleware.
  humanURL: https://connexion.readthedocs.io/en/latest/middleware.html
  baseURL: https://connexion.readthedocs.io
  tags:
  - ASGI
  - Middleware
  - WSGI
  properties:
  - type: Documentation
    url: https://connexion.readthedocs.io/en/latest/middleware.html
  - type: Reference
    url: https://github.com/spec-first/connexion/tree/main/connexion/middleware
  x-features:
  - Routing, security, request, and response validation middleware
  - SwaggerUIMiddleware for interactive docs
  - LifespanMiddleware for startup and shutdown hooks
  - ContextMiddleware to propagate request context
  x-useCases:
  - Add Connexion validation to FastAPI or Starlette
  - Wrap an existing WSGI application without rewriting handlers
  - Customize the middleware stack for a specific deployment
common:
- type: DomainSecurity
  url: security/connexion-domain-security.yml
- type: Website
  url: https://connexion.readthedocs.io/
- type: Documentation
  url: https://connexion.readthedocs.io/en/latest/quickstart.html
- type: GitHubRepository
  url: https://github.com/spec-first/connexion
- type: GitHubOrganization
  url: https://github.com/spec-first
- type: Issue Tracker
  url: https://github.com/spec-first/connexion/issues
- type: ChangeLog
  url: https://github.com/spec-first/connexion/releases
- type: License
  url: https://github.com/spec-first/connexion/blob/main/LICENSE
- type: PyPI
  url: https://pypi.org/project/connexion/
- url: https://github.com/spec-first/connexion/releases.atom
  type: Blog
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Connexion

Kin Score

APIs 2

Connexion Python Framework

Connexion Middleware Stack

Pricing Plans 1

Connexion Plans Pricing