Connexions¶

Connexions is a mock server generator for OpenAPI specifications.
It allows you to define multiple APIs and generate meaningful mock responses automatically.
You can also define static responses for any arbitrary path.

Goals¶

provide a simple tool to work with API mocks
combine multiple APIs into one server
generate meaningful responses

Features¶

Multiple APIs on one server - each spec becomes a service with its own URL prefix
Upstream proxy with circuit breaker - forward to real backends with fallback to mocks
Latency & error simulation - test how your app handles delays and failures
Custom middleware - modify requests/responses on the fly
Response caching - cache GET responses for consistency
Request validation - validate against OpenAPI spec

Real-World Validation¶

Connexions continuously generates and validates data against 2,200+ real-world OpenAPI specifications from mockzilla/specs:

Total: 2215 services, 98464 endpoints
✅ Success: 98464  ❌ Fails: 0

Modes¶

Connexions runs in two modes:

Portable - point at OpenAPI specs and run. No code generation, no setup.
Codegen - generate typed Go handlers with custom logic and middleware.

Quick Start¶

Homebrew¶

brew tap mockzilla/tap
brew install connexions
connexions https://petstore3.swagger.io/api/v3/openapi.json

Go¶

go run github.com/mockzilla/connexions/v2/cmd/server@latest \
  https://petstore3.swagger.io/api/v3/openapi.json

Templates¶

Portable template - embed specs into a single binary via go:embed
Codegen template - generate Go handlers with custom logic and middleware

Read full documentation at mockzilla.github.io/connexions.

OpenAPI Specification

License¶

Licensed under the MIT License