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OpenAPI Generator, eller?

Generate OpenAPI v3 clients and servers from the command line with nothing more than Node.js.

Just run:

npm i -g openapi-eller

See openapi-eller --help for usage details.

Looking for an easy way to generate a mock server from an OpenAPI v3 spec? We've got you covered.

Try openapi-mock-eller today!

PLEASE NOTE: This codebase is still a work-in-progress, but it does produce production-grade code for those targets listed as supported. Behaviour is subject to change between variants until 1.0.0.


  • Supports* the full OpenAPI v3 specification
  • Uses an interceptor pattern for handling security schemas in clients
  • OAuth 2 clients comply with RFC6749 and RFC6750 (Bearer Token Usage)
  • Targets can be configured with a JSON or YAML file for simple, reproducable generations
  • Easily extensible Handlebars templates for core structure of files, with TypeScript target-specific code for handling with pointy bits

Supported targets

  • Clients:
    • Kotlin (Android)
    • Swift (iOS)
    • TypeScript
  • Servers:
    • ASP.NET (MVC Framework 4.5)

There are other targets in the tree, though they are a work-in-progress.

Roadmap to 0.4

  • Generating platform-conformant API documentation
  • Handle returning headers, status codes and raw response objects where necessary
  • Handle mandatory configuration for targets
  • Generate documentation for target configuration


  • The Techno Creatives


We happily accept contributions! We simply ask that you please make sure that any dependencies of your targets use a permissive license compatible with the ISC license (which means no AGPL or GPL dependencies, unfortunately.)

If you're unsure, open an issue and we can help you out!


ISC license - see LICENSE file.

Any code outputted by this generator is the license of your choice.